Petroleum and natural gas industries -- Specific requirements for offshore structures

This document provides requirements and guidelines for marine geophysical investigations. It is applicable to operators/end users, contractors and public and regulatory authorities concerned with marine site investigations for offshore structures for petroleum and natural gas industries. This document provides requirements, specifications, and guidance for: a) objectives, planning, and quality management; b) positioning; c) seafloor mapping, including instrumentation and acquisition parameters, acquisition methods, and deliverables; d) sub-seafloor mapping, including seismic instrumentation and acquisition parameters, and non-seismic-reflection methods; e) reporting; f) data integration, interpretation, and investigation of geohazards. This document is applicable to investigation of the seafloor and the sub-seafloor, from shallow coastal waters to water depths of 3 000 m and more. It provides guidance for the integration of the results from marine soil investigations and marine geophysical investigations with other relevant datasets. NOTE 1 The depth of interest for sub-seafloor mapping depends on the objectives of the investigation. For offshore construction, the depths of investigation are typically in the range 1 m below seafloor to 200 m below seafloor. Some methods for sub-seafloor mapping can also achieve much greater investigation depths, for example for assessing geohazards for hydrocarbon well drilling. There is a fundamental difference between seafloor mapping and sub-seafloor mapping: seafloor signal resolution can be specified, while sub-seafloor signal resolution and penetration cannot. This document therefore contains requirements for the use of certain techniques for certain types of seafloor mapping and sub-seafloor mapping (similarly, requirements are given for certain aspects of data processing). If other techniques can be shown to obtain the same information, with the same or better resolution and accuracy, then those techniques may be used. Mapping of pre-drilling well-site geohazards beneath the seafloor is part of the scope of this document. NOTE 2 This implies depths of investigation that are typically 200 m below the first pressure-containment casing string or 1 000 m below the seafloor, whichever is greatest. Mapping of pre-drilling well-site geohazards is therefore the deepest type of investigation covered by this document. In this document, positioning information relates only to the positioning of survey platforms, sources and receivers. The processes used to determine positions of seafloor and sub-seafloor data points are not covered in this document. Guidance only is given in this document for the use of marine shear waves (A.8.3.3), marine surface waves (A.8.3.4), electrical resistivity imaging (A.8.3.5) and electromagnetic imaging (A.8.3.6).

Industries du pétrole et du gaz naturel -- Exigences spécifiques relatives aux structures en mer

General Information

Status
Published
Publication Date
22-Mar-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
02-Dec-2020
Completion Date
01-Dec-2020
Ref Project

Buy Standard

Standard
ISO 19901-10:2021 - Petroleum and natural gas industries -- Specific requirements for offshore structures
English language
81 pages
sale 15% off
Preview
sale 15% off
Preview
Draft
ISO/FDIS 19901-10:Version 13-okt-2020 - Petroleum and natural gas industries -- Specific requirements for offshore structures
English language
79 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL ISO
STANDARD 19901-10
First edition
2021-03
Petroleum and natural gas
industries — Specific requirements
for offshore structures —
Part 10:
Marine geophysical investigations
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 10: Enquêtes géophysiques marines
Reference number
ISO 19901-10:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 19901-10:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 19901-10:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 2

3  Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and abbreviated terms ........................................................................................................................................................12

4.1 Symbols ......................................................................................................................................................................................................12

4.2 Abbreviated terms ............................................................................................................................................................................13

5  Objectives, planning, and quality management ................................................................................................................14

5.1 General ........................................................................................................................................................................................................14

5.1.1 Objectives and project specifications ..........................................................................................................14

5.1.2 Georeferencing and GIS ...........................................................................................................................................15

5.1.3 Ground model ..................................................................................................................................................................15

5.2 Desk study ................................................................................................................................................................................................16

5.2.1 General...................................................................................................................................................................................16

5.2.2 Use of exploration 2D and 3D seismic data in a desk study ....................................................17

5.2.3 Desk study for pre-drilling well-site investigations .......................................................................17

5.3 Scoping and planning .....................................................................................................................................................................17

5.3.1 General...................................................................................................................................................................................17

5.3.2 Scoping of seafloor mapping and sub-seafloor mapping ...........................................................19

5.4 Operations planning and data quality management ...........................................................................................22

5.4.1 Quality plan .......................................................................................................................................................................22

5.4.2 Effects of attenuation ................................................................................................................................................23

5.4.3 Data quality management .....................................................................................................................................23

6 Positioning ...............................................................................................................................................................................................................23

6.1 General ........................................................................................................................................................................................................23

6.2 Coordinate reference systems ................................................................................................................................................24

6.2.1 Horizontal coordinate reference system ..................................................................................................24

6.2.2 Vertical coordinate reference system..........................................................................................................24

6.3 Surface positioning requirements .......................................................................................................................................25

6.4 Vessel heading ......................................................................................................................................................................................25

6.4.1 General...................................................................................................................................................................................25

6.4.2 Gyro compass ...................................................................................................................................................................25

6.4.3 GNSS based heading reference .........................................................................................................................26

6.4.4 Alignment ............................................................................................................................................................................26

6.5 Sub-sea positioning — Ultra-short baseline system ...........................................................................................26

6.6 Inertial navigation system ..........................................................................................................................................................27

6.7 Auxiliary sensor: doppler velocity log .............................................................................................................................27

6.8 Auxiliary sensor: altimeter ........................................................................................................................................................27

6.9 Auxiliary sensor: pressure-depth sensor ......................................................................................................................28

7  Seafloor mapping ..............................................................................................................................................................................................28

7.1 General ........................................................................................................................................................................................................28

7.2 Instrumentation and acquisition parameters ...........................................................................................................29

7.2.1 Multi-beam echo sounder .....................................................................................................................................29

7.2.2 Side scan sonar ...............................................................................................................................................................31

7.2.3 Auxiliary sensor: velocity of sound in seawater ................................................................................31

7.3 Data acquisition methods ...........................................................................................................................................................32

7.3.1 General...................................................................................................................................................................................32

7.3.2 Reconnaissance seafloor mapping ................................................................................................................32

7.3.3 Engineering seafloor mapping ..........................................................................................................................33

7.3.4 Detailed engineering seafloor mapping ....................................................................................................33

7.4 Seafloor mapping deliverables ...............................................................................................................................................33

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 19901-10:2021(E)

8  Sub-seafloor mapping ..................................................................................................................................................................................34

8.1 General ........................................................................................................................................................................................................34

8.1.1 Resolution and signal penetration ................................................................................................................34

8.1.2 Equipment selection for sub-seafloor mapping methods .........................................................35

8.1.3 Assessment of data quality ..................................................................................................................................35

8.1.4 Deliverables .......................................................................................................................................................................36

8.2 Acquisition equipment and parameters for seismic data ...............................................................................36

8.2.1 Equipment performance ........................................................................................................................................36

8.2.2 Acquisition and processing parameters ...................................................................................................37

8.2.3 High resolution seismic reflection .................................................................................................................40

8.2.4 Ultra-high-resolution seismic reflection ..................................................................................................44

8.2.5 Ultra-ultra-high resolution seismic reflection .....................................................................................44

8.2.6 Sub-bottom profiling .................................................................................................................................................45

8.3 Non-seismic reflection methods ...........................................................................................................................................46

8.3.1 Seismic refraction ........................................................................................................................................................46

8.3.2 Magnetometer and magnetic gradiometer.............................................................................................47

8.3.3 Marine shear waves ....................................................................................................................................................47

8.3.4 Marine surface waves ...............................................................................................................................................48

8.3.5 Electrical resistivity imaging ..............................................................................................................................48

8.3.6 Electromagnetic imaging .......................................................................................................................................48

9  Reporting of seafloor mapping and sub-seafloor mapping ..................................................................................48

9.1 General ........................................................................................................................................................................................................48

9.2 Record of data acquisition operations .............................................................................................................................48

9.3 Record of data processing ..........................................................................................................................................................49

9.4 Results report ........................................................................................................................................................................................49

10 Data integration, interpretation and investigation of geohazards................................................................50

10.1 General ........................................................................................................................................................................................................50

10.2 Horizons, isopachs and isochores .......................................................................................................................................50

10.3 Mapping stratigraphic units and defining geochronology .............................................................................50

10.4 Time-to-depth conversion .........................................................................................................................................................51

10.5 Borehole geophysical logging ..................................................................................................................................................51

10.6 Investigation of geohazards ......................................................................................................................................................52

10.7 Integrated studies ......... .....................................................................................................................................................................52

Annex A (informative) Additional information and guidance ................................................................................................53

Bibliography .............................................................................................................................................................................................................................78

iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 19901-10:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore

structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore

structures.
A list of all parts in the ISO 19901 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 19901-10:2021(E)
Introduction

The general objective of a marine site investigation is to provide information about the seafloor, the

sub-seafloor and geological processes affecting both, geohazards, and human-made objects at or

below the seafloor. Marine site investigations can encompass both marine soil investigations and

marine geophysical investigations, as shown in Figure 1. This document provides requirements for

marine geophysical investigations to support oil and gas developments offshore, is complementary to

ISO 19901-8 on marine soil investigations, and provides guidance on the integration of both types of

investigations.

Figure 1 — Marine geophysical investigations as part of marine site investigations.

NOTE Subjects denoted in grey boxes in Figure 1 are neither covered in ISO 19901-8 nor in this document.

However, marine geophysical investigations can provide information about soils and rocks, whereas rocks are

only covered by ISO 19910-8 to the extent that ordinary marine soil investigation tools can be used, e.g. for chalk.

Marine site investigations for a specific project can comprise both geophysical and geotechnical

investigations, depending on project scale and complexity. It is common practice to conduct first a

marine geophysical investigation, sometimes in combination with a limited marine soil investigation

consisting of shallow soil sampling and/or in situ testing. A more extensive marine soil investigation

is often conducted at a later stage. In some cases, a marine site investigation can consist solely of a

stand-alone geophysical survey that has a specific and limited purpose. A marine site investigation

can also consist solely of a stand-alone marine soil investigation, for which details on soil investigation

equipment and procedures are provided in ISO 19901-8.

Particular objectives of a marine geophysical investigation should be addressed in project specifications,

which should specify desired investigation depths, desired resolutions (horizontal and vertical), and

whether the objective is to illuminate the seafloor and/or the sub-seafloor. Caution is necessary in

the selection of the type of equipment to be used, and operational parameters for that equipment, in

order to meet those desired depths, resolutions, and illumination targets, particularly because local

site conditions can affect the abilities of certain equipment to meet those objectives. This document

includes discussion of the selection and operation of appropriate geophysical equipment.

Marine geophysical investigations and marine soil investigations can be (and often are) carried out as

separate exercises, the results of which can be integrated into a ground model. This document applies

to critical stages in the development of a ground model, from the initial conception stage through

successive stages of increased detail.
In this document, the following verbal forms are used:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “can” indicates a possibility or a capability;
— “may” indicates a permission.

Annex A provides additional information intended to assist the understanding or use of this document.

vi © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 19901-10:2021(E)
Petroleum and natural gas industries — Specific
requirements for offshore structures —
Part 10:
Marine geophysical investigations
1 Scope

This document provides requirements and guidelines for marine geophysical investigations. It is

applicable to operators/end users, contractors and public and regulatory authorities concerned with

marine site investigations for offshore structures for petroleum and natural gas industries.

This document provides requirements, specifications, and guidance for:
a) objectives, planning, and quality management;
b) positioning;

c) seafloor mapping, including instrumentation and acquisition parameters, acquisition methods, and

deliverables;

d) sub-seafloor mapping, including seismic instrumentation and acquisition parameters, and non-

seismic-reflection methods;
e) reporting;
f) data integration, interpretation, and investigation of geohazards.

This document is applicable to investigation of the seafloor and the sub-seafloor, from shallow coastal

waters to water depths of 3 000 m and more. It provides guidance for the integration of the results from

marine soil investigations and marine geophysical investigations with other relevant datasets.

NOTE 1 The depth of interest for sub-seafloor mapping depends on the objectives of the investigation. For

offshore construction, the depths of investigation are typically in the range 1 m below seafloor to 200 m below

seafloor. Some methods for sub-seafloor mapping can also achieve much greater investigation depths, for

example for assessing geohazards for hydrocarbon well drilling.

There is a fundamental difference between seafloor mapping and sub-seafloor mapping: seafloor signal

resolution can be specified, while sub-seafloor signal resolution and penetration cannot. This document

therefore contains requirements for the use of certain techniques for certain types of seafloor mapping

and sub-seafloor mapping (similarly, requirements are given for certain aspects of data processing). If

other techniques can be shown to obtain the same information, with the same or better resolution and

accuracy, then those techniques may be used.

Mapping of pre-drilling well-site geohazards beneath the seafloor is part of the scope of this document.

NOTE 2 This implies depths of investigation that are typically 200 m below the first pressure-containment

casing string or 1 000 m below the seafloor, whichever is greatest. Mapping of pre-drilling well-site geohazards

is therefore the deepest type of investigation covered by this document.

In this document, positioning information relates only to the positioning of survey platforms, sources

and receivers. The processes used to determine positions of seafloor and sub-seafloor data points are

not covered in this document.

Guidance only is given in this document for the use of marine shear waves (A.8.3.3), marine surface

waves (A.8.3.4), electrical resistivity imaging (A.8.3.5) and electromagnetic imaging (A.8.3.6).

© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 19901-10:2021(E)
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 19901-8, Petroleum and natural gas industries — Specific requirements for offshore structures —

Part 8: Marine soil investigations
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
abyssal water
water depths greater than 3 000 m
3.2
acoustic impedance
seismic velocity multiplied by density

Note 1 to entry: Compressional-wave impedance uses compressional-wave velocity, and shear-wave impedance

uses shear-wave velocity.
3.3
acoustic noise
unwanted acoustic signal
3.4
active tail buoy

buoy fitted with a global navigation satellite system transponder attached to the end of a streamer

3.5
airgun
seismic source that injects a bubble of highly compressed air into the water

Note 1 to entry: Whereas single airguns can be used, it is common practise to deploy and fire several airguns in

arrays to produce an acoustic pulse that has certain temporal and spatial characteristics.

3.6
aliasing

effect that causes signals to be misrepresented in recorded data as a result of undersampling

Note 1 to entry: Undersampling can be in time or spatial domain.
3.7
anisotropy
dependence of velocity on direction or upon angle of wave propagation
3.8
array

system of linked hydrophones or seismic sources arranged in a geometric pattern to increase sensitivity

and/or directionality and/or in the case of a seismic source, the pulse characteristics

2 © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 19901-10:2021(E)
3.9
attenuation
reduction in amplitude or energy

Note 1 to entry: Attenuation in seismic data is related in part to soil conditions.

3.10
attribute
characteristic of a given object, structure or feature

Note 1 to entry: A seismic attribute is a quantity or property derived or extracted from seismic data that provides

specific information contained within the data as an aid in interpretation.
3.11
backscatter

amplitude of echo sounder energy reflected by the seafloor that can be processed into information

about seafloor features and texture
3.12
bandwidth
range of frequencies in an acoustic signal between the two half power points

Note 1 to entry: This corresponds with the frequencies at which the power drops to half the peak power (3 dB).

3.13
boomer
seismic source that operates by the rapid movement of a restricted metal plate
3.14
chirp

type of sub-bottom profiler that emits a frequency-modulated pulse of acoustic energy over a specified

range of frequencies
3.15
common depth point
CDP

common reflection point at depth on a reflector, or the halfway point when a wave travels from a source

to a reflector to a receiver

Note 1 to entry: In the case of flat layers, the common depth point is vertically below the common mid-point.

3.16
common mid-point
CMP

in multichannel seismic acquisition, the point on the surface halfway between the source and receiver

that is shared by a number of source-receiver pairs

Note 1 to entry: CMP gather refers to the set of traces that have a common mid-point.

3.17
common reference point

datum point on a vessel to which all positioning systems are referenced in three dimensions

3.18
cone penetration test
CPT
CPTU

in situ soil strength testing device that makes direct measurements of cone resistance, sleeve friction

and pore pressure response as it is pushed into the sub-seafloor
Note 1 to entry: See ISO 19901-8.
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 19901-10:2021(E)
3.19
contractor
party or person responsible for an assigned scope
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 19901-10
ISO/TC 67/SC 7
Petroleum and natural gas
Secretariat: BSI
industries — Specific requirements
Voting begins on:
2020-10-06 for offshore structures —
Voting terminates on:
Part 10:
2020-12-01
Marine geophysical investigations
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 10: Enquêtes géophysiques marines
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 19901-10:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2020
---------------------- Page: 1 ----------------------
ISO/FDIS 19901-10:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 19901-10:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 2

3  Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and abbreviated terms ........................................................................................................................................................12

4.1 Symbols ......................................................................................................................................................................................................12

4.2 Abbreviated terms ............................................................................................................................................................................13

5  Objectives, planning, and quality management ................................................................................................................14

5.1 General ........................................................................................................................................................................................................14

5.1.1 Objectives and project specifications ..........................................................................................................14

5.1.2 Georeferencing and GIS ...........................................................................................................................................15

5.1.3 Ground model ..................................................................................................................................................................15

5.2 Desk study ................................................................................................................................................................................................16

5.2.1 General...................................................................................................................................................................................16

5.2.2 Use of exploration 2D and 3D seismic data in a desk study ....................................................17

5.2.3 Desk study for pre-drilling well-site investigations .......................................................................17

5.3 Scoping and planning .....................................................................................................................................................................17

5.3.1 General...................................................................................................................................................................................17

5.3.2 Scoping of seafloor mapping and sub-seafloor mapping ...........................................................19

5.4 Operations planning and data quality management ...........................................................................................22

5.4.1 Quality plan .......................................................................................................................................................................22

5.4.2 Effects of attenuation ................................................................................................................................................23

5.4.3 Data quality management .....................................................................................................................................23

6 Positioning ...............................................................................................................................................................................................................23

6.1 General ........................................................................................................................................................................................................23

6.2 Coordinate reference systems ................................................................................................................................................24

6.2.1 Horizontal coordinate reference system ..................................................................................................24

6.2.2 Vertical coordinate reference system..........................................................................................................24

6.3 Surface positioning requirements .......................................................................................................................................25

6.4 Vessel heading ......................................................................................................................................................................................25

6.4.1 General...................................................................................................................................................................................25

6.4.2 Gyro compass ...................................................................................................................................................................25

6.4.3 GNSS based heading reference .........................................................................................................................26

6.4.4 Alignment ............................................................................................................................................................................26

6.5 Sub-sea positioning — Ultra-short baseline system ...........................................................................................26

6.6 Inertial navigation system ..........................................................................................................................................................27

6.7 Auxiliary sensor: doppler velocity log .............................................................................................................................27

6.8 Auxiliary sensor: altimeter ........................................................................................................................................................28

6.9 Auxiliary sensor: pressure-depth sensor ......................................................................................................................28

7  Seafloor mapping ..............................................................................................................................................................................................28

7.1 General ........................................................................................................................................................................................................28

7.2 Instrumentation and acquisition parameters ...........................................................................................................29

7.2.1 Multi-beam echo sounder .....................................................................................................................................29

7.2.2 Side scan sonar ...............................................................................................................................................................31

7.2.3 Auxiliary sensor: velocity of sound in seawater ................................................................................31

7.3 Data acquisition methods ...........................................................................................................................................................32

7.3.1 General...................................................................................................................................................................................32

7.3.2 Reconnaissance seafloor mapping ................................................................................................................32

7.3.3 Engineering seafloor mapping ..........................................................................................................................32

7.3.4 Detailed engineering seafloor mapping ....................................................................................................33

7.4 Seafloor mapping deliverables ...............................................................................................................................................33

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 19901-10:2020(E)

8  Sub-seafloor mapping ..................................................................................................................................................................................34

8.1 General ........................................................................................................................................................................................................34

8.1.1 Resolution and signal penetration ................................................................................................................34

8.1.2 Equipment selection for sub-seafloor mapping methods .........................................................34

8.1.3 Assessment of data quality ..................................................................................................................................35

8.1.4 Deliverables .......................................................................................................................................................................35

8.2 Acquisition equipment and parameters for seismic data ...............................................................................36

8.2.1 Equipment performance ........................................................................................................................................36

8.2.2 Acquisition and processing parameters ...................................................................................................36

8.2.3 High resolution seismic reflection .................................................................................................................39

8.2.4 Ultra-high-resolution seismic reflection ..................................................................................................43

8.2.5 Ultra-ultra-high resolution seismic reflection .....................................................................................44

8.2.6 Sub-bottom profiling .................................................................................................................................................44

8.3 Non-seismic reflection methods ...........................................................................................................................................46

8.3.1 Seismic refraction ........................................................................................................................................................46

8.3.2 Magnetometer and magnetic gradiometer.............................................................................................47

8.3.3 Marine shear waves ....................................................................................................................................................47

8.3.4 Marine surface waves ...............................................................................................................................................47

8.3.5 Electrical resistivity imaging ..............................................................................................................................47

8.3.6 Electromagnetic imaging .......................................................................................................................................47

9  Reporting of seafloor mapping and sub-seafloor mapping ..................................................................................47

9.1 General ........................................................................................................................................................................................................47

9.2 Record of data acquisition operations .............................................................................................................................48

9.3 Record of data processing ..........................................................................................................................................................49

9.4 Results report ........................................................................................................................................................................................49

10 Data integration, interpretation and investigation of geohazards................................................................49

10.1 General ........................................................................................................................................................................................................49

10.2 Horizons, isopachs and isochores .......................................................................................................................................50

10.3 Mapping stratigraphic units and defining geochronology .............................................................................50

10.4 Time-to-depth conversion .........................................................................................................................................................51

10.5 Borehole geophysical logging ..................................................................................................................................................51

10.6 Investigation of geohazards ......................................................................................................................................................51

10.7 Integrated studies ......... .....................................................................................................................................................................51

Annex A (informative) Additional information and guidance ................................................................................................52

Bibliography .............................................................................................................................................................................................................................76

iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 19901-10:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore

structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore

structures.
A list of all parts in the ISO 19901 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/FDIS 19901-10:2020(E)
Introduction

The general objective of a marine site investigation is to provide information about the seafloor,

the sub-seafloor and geological processes affecting both, geohazards, and man-made objects at or

below the seafloor. Marine site investigations can encompass both marine soil investigations and

marine geophysical investigations, as shown in Figure 1. This document provides requirements for

marine geophysical investigations to support oil and gas developments offshore, is complementary to

ISO 19901-8 on marine soil investigations, and provides guidance on the integration of both types of

investigations.

Figure 1 — Marine geophysical investigations as part of marine site investigations.

NOTE Subjects denoted in grey boxes in Figure 1 are neither covered in ISO 19901-8 nor in this document.

However, marine geophysical investigations can provide information about soils and rocks, whereas rocks are

only covered by ISO 19910-8 to the extent that ordinary marine soil investigation tools can be used, e.g. for chalk.

Marine site investigations for a specific project can comprise both geophysical and geotechnical

investigations, depending on project scale and complexity. It is common practice to conduct first a

marine geophysical investigation, sometimes in combination with a limited marine soil investigation

consisting of shallow soil sampling and/or in situ testing. A more extensive marine soil investigation

is often conducted at a later stage. In some cases, a marine site investigation can consist solely of a

stand-alone geophysical survey that has a specific and limited purpose. A marine site investigation

can also consist solely of a stand-alone marine soil investigation, for which details on soil investigation

equipment and procedures are provided in ISO 19901-8.

Particular objectives of a marine geophysical investigation should be addressed in project specifications,

which should specify desired investigation depths, desired resolutions (horizontal and vertical), and

whether the objective is to illuminate the seafloor and/or the sub-seafloor. Caution is necessary in

the selection of the type of equipment to be used, and operational parameters for that equipment, in

order to meet those desired depths, resolutions, and illumination targets, particularly because local

site conditions may affect the abilities of certain equipment to meet those objectives. This document

includes discussion of the selection and operation of appropriate geophysical equipment.

Marine geophysical investigations and marine soil investigations can be (and often are) carried out as

separate exercises, the results of which can be integrated into a ground model. This document applies

to critical stages in the development of a ground model, from the initial conception stage through

successive stages of increased detail.
In this document, the following verbal forms are used:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “can” indicates a possibility or a capability;
— “may” indicates a permission.

Annex A provides additional information intended to assist the understanding or use of this document.

vi © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 19901-10:2020(E)
Petroleum and natural gas industries — Specific
requirements for offshore structures —
Part 10:
Marine geophysical investigations
1 Scope

This document provides requirements and guidelines for marine geophysical investigations. It is

applicable to operators/end users, contractors and public and regulatory authorities concerned with

marine site investigations for offshore structures for petroleum and natural gas industries.

This document provides requirements, specifications, and guidance for:
a) objectives, planning, and quality management;
b) positioning;

c) seafloor mapping, including instrumentation and acquisition parameters, acquisition methods, and

deliverables;

d) sub-seafloor mapping, including seismic instrumentation and acquisition parameters, and non-

seismic-reflection methods;
e) reporting;
f) data integration, interpretation, and investigation of geohazards.

This document is applicable to investigation of the seafloor and the sub-seafloor, from shallow coastal

waters to water depths of 3 000 m and more. It provides guidance for the integration of the results from

marine soil investigations and marine geophysical investigations with other relevant datasets.

NOTE 1 The depth of interest for sub-seafloor mapping depends on the objectives of the investigation. For

offshore construction, the depths of investigation are typically in the range 1 m below seafloor to 200 m below

seafloor. Some methods for sub-seafloor mapping can also achieve much greater investigation depths, for

example for assessing geohazards for hydrocarbon well drilling.

There is a fundamental difference between seafloor mapping and sub-seafloor mapping: seafloor signal

resolution can be specified, while sub-seafloor signal resolution and penetration cannot. This document

therefore contains requirements for the use of certain techniques for certain types of seafloor mapping

and sub-seafloor mapping (similarly, requirements are given for certain aspects of data processing). If

other techniques can be shown to obtain the same information, with the same or better resolution and

accuracy, then those techniques may be used.

Mapping of pre-drilling well-site geohazards beneath the seafloor is part of the scope of this document.

NOTE 2 This implies depths of investigation that are typically 200 m below the first pressure-containment

casing string or 1 000 m below the seafloor, whichever is greatest. Mapping of pre-drilling well-site geohazards

is therefore the deepest type of investigation covered by this document.

In this document, positioning information relates only to the positioning of survey platforms, sources

and receivers. The processes used to determine positions of seafloor and sub-seafloor data points are

not covered in this document.

Guidance only is given in this document for the use of marine shear waves (A.8.3.3), marine surface

waves (A.8.3.4), electrical resistivity imaging (A.8.3.5) and electromagnetic imaging (A.8.3.6).

© ISO 2020 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO/FDIS 19901-10:2020(E)
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 19901-8, Petroleum and natural gas industries — Specific requirements for offshore structures —

Part 8: Marine soil investigations
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
abyssal water
water depths greater than 3 000 m
3.2
acoustic impedance
seismic velocity multiplied by density

Note 1 to entry: Compressional-wave impedance uses compressional-wave velocity, and shear-wave impedance

uses shear-wave velocity.
3.3
acoustic noise
unwanted acoustic signal
3.4
active tail buoy

buoy fitted with a global navigation satellite system transponder attached to the end of a streamer

3.5
airgun
seismic source that injects a bubble of highly compressed air into the water

Note 1 to entry: Whereas single airguns can be used, it is common practise to deploy and fire several airguns in

arrays to produce an acoustic pulse that has certain temporal and spatial characteristics.

3.6
aliasing

effect that causes signals to be misrepresented in recorded data as a result of undersampling

Note 1 to entry: Undersampling can be in time or spatial domain.
3.7
anisotropy
dependence of velocity on direction or upon angle of wave propagation
3.8
array

system of linked hydrophones or seismic sources arranged in a geometric pattern to increase sensitivity

and/or directionality and/or in the case of a seismic source, the pulse characteristics

2 © ISO 2020 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/FDIS 19901-10:2020(E)
3.9
attenuation
reduction in amplitude or energy

Note 1 to entry: Attenuation in seismic data is related in part to soil conditions.

3.10
attribute
characteristic of a given object, structure or feature

Note 1 to entry: A seismic attribute is a quantity or property derived or extracted from seismic data that provides

specific information contained within the data as an aid in interpretation.
3.11
backscatter

amplitude of echo sounder energy reflected by the seafloor that can be processed into information

about seafloor features and texture
3.12
bandwidth
range of frequencies in an acoustic signal between the two half power points

Note 1 to entry: This corresponds with the frequencies at which the power drops to half the peak power (3 dB).

3.13
boomer
seismic source that operates by the rapid movement of a restricted metal plate
3.14
chirp

type of sub-bottom profiler that emits a frequency-modulated pulse of acoustic energy over a specified

range of frequencies
3.15
common depth point
CDP

common reflection point at depth on a reflector, or the halfway point when a wave travels from a source

to a reflector to a receiver

Note 1 to entry: In the case of flat layers, the common depth point is vertically below the common mid-point.

3.16
common mid-point
CMP

in multichannel seismic acquisition, the point on the surface halfway between the source and receiver

that is shared by a number of source-receiver pairs
Note
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.