ASTM E1675-04e1
(Practice)Standard Practice for Sampling Two-Phase Geothermal Fluid for Purposes of Chemical Analysis
Standard Practice for Sampling Two-Phase Geothermal Fluid for Purposes of Chemical Analysis
SIGNIFICANCE AND USE
The objective of this practice is to obtain representative samples of the steam and liquid phases as they exist in the pipeline at the sample point, without allowing steam condensation or additional liquid flashing in the separator. A significant feature of the practice is the use of a cyclone-type separator for high-efficiency phase separation which is operated at flow rates high enough to prevent significant heat loss while maintaining an internal pressure essentially the same as the pipeline pressure.
Another significant feature of the practice is to locate the sampling separator at a point on the pipeline where the two-phase flow is at least partially stratified to aid in the separation process. It is neither necessary nor possible to pass representative proportions of each phase through the sampling separator to obtain representative samples. The separator is usually attached to an appropriately oriented port to collect each specific phase—normally on top of the line for steam and at the bottom for liquid. In some cases, piping configurations can generate unusual flow regimes where the reverse is required. If the ratio of one phase to another is not extreme, representative samples of each phase can often be obtained from a horizontal port on the side of the pipeline.
This practice is used whenever liquid or steam samples, or both, must be collected from a two-phase discharge for chemical analysis. This typically includes initial well-testing operations when a well is discharged to the atmosphere or routine well production when a well discharges to a fluid gathering system and power plant. The combined two-phase flow of several wells producing through a common gathering system may also be sampled in accordance with this practice.
This practice is not typically employed when individual wells produce to dedicated production separators. In these cases, the separated steam and liquid at the outlet of the production separator is sampled in accordance with singl...
SCOPE
1.1 The purpose of this practice is to obtain representative samples of liquid and steam as they exist in a pipeline transporting two-phase geothermal fluids.
1.1.1 The liquid and steam samples are collected and properly preserved for subsequent chemical analysis in the field or an off-site analytical laboratory.
1.1.2 The chemical composition data generated from the analysis of liquid and steam samples may be used for many applications important to geothermal energy exploration, development, and the long-term managed exploitation of geothermal resources. These applications include, but are not limited to, resource evaluations such as determining reservoir temperature and the origin of reservoir fluids, compatibility of produced fluids with production, power generation and reinjection hardware exposed to the fluids (corrosivity and scale deposition potential), long-term reservoir monitoring during field exploitation, and environmental impact evaluations including emissions testing.
1.1.2.1 To fully utilize the chemical composition data in the applications stated in 1.1.2, specific physical data related to the two-phase discharge, wellbore, and geothermal reservoir may be required. Mathematical reconstruction of the fluid chemistry (liquid and steam) to reservoir conditions is a primary requirement in many applications. At a minimum, this requires precise knowledge of the total fluid enthalpy and pressure or temperature at the sample point. Fluid reconstruction and computations to conditions different from the sample collection point are beyond the scope of this practice.
1.2 This practice is limited to the collection of samples from two-phase flow streams at pressures greater than 70 kPa gauge (10 psig) and having a volumetric vapor fraction of at least 20 %. This practice is not applicable to single-phase flow streams such as pumped liquid discharges at pressures above the flash point or superheated steam flows. Ref...
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Designation: E1675 − 04
StandardPractice for
Sampling Two-Phase Geothermal Fluid for Purposes of
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Chemical Analysis
This standard is issued under the fixed designation E1675; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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´ NOTE—Editorial changes were made throughout in June 2004.
1. Scope the flash point or superheated steam flows. Refer to Specifica-
tion E947 for sampling single-phase geothermal fluids.
1.1 The purpose of this practice is to obtain representative
samples of liquid and steam as they exist in a pipeline 1.3 The sampling of geothermal fluid two-phase flow
transporting two-phase geothermal fluids. streams (liquid and steam) requires specialized sampling
1.1.1 The liquid and steam samples are collected and equipment and proper orientation of sample ports with respect
properly preserved for subsequent chemical analysis in the to the two-phase flow line. This practice is applicable to wells
field or an off-site analytical laboratory. not equipped with individual production separators.
1.1.2 The chemical composition data generated from the
1.4 In many cases, these techniques are the only possible
analysis of liquid and steam samples may be used for many
way to obtain representative steam and liquid samples from
applications important to geothermal energy exploration,
individual producing geothermal wells. The sampling prob-
development, and the long-term managed exploitation of
lems that exist include the following:
geothermal resources. These applications include, but are not
1.4.1 Unstable production flow rates that have a large
limited to, resource evaluations such as determining reservoir
degree of surging,
temperature and the origin of reservoir fluids, compatibility of
1.4.2 Unknown percentage of total flow that is flashed to
produced fluids with production, power generation and rein-
steam or is continuously flashing through the production
jection hardware exposed to the fluids (corrosivity and scale
system,
deposition potential), long-term reservoir monitoring during
1.4.3 Mineral deposition during and after flashing of the
field exploitation, and environmental impact evaluations in-
produced fluid in wellbores, production piping, and sampling
cluding emissions testing.
trains,
1.1.2.1 To fully utilize the chemical composition data in the
1.4.4 Stratification of flow inside the pipeline and unusual
applications stated in 1.1.2, specific physical data related to the
flow regimes at the sampling ports, and
two-phase discharge, wellbore, and geothermal reservoir may
1.4.5 Insufficient flash fraction to obtain a steam sample.
berequired.Mathematicalreconstructionofthefluidchemistry
1.5 This practice covers the sample locations, specialized
(liquid and steam) to reservoir conditions is a primary require-
sampling equipment, and procedures needed to obtain repre-
mentinmanyapplications.Ataminimum,thisrequiresprecise
sentative liquid and steam samples for chemical analysis.
knowledge of the total fluid enthalpy and pressure or tempera-
ture at the sample point. Fluid reconstruction and computations
1.6 This standard does not purport to address all of the
to conditions different from the sample collection point are safety concerns, if any, associated with its use. It is the
beyond the scope of this practice.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.2 Thispracticeislimitedtothecollectionofsamplesfrom
bility of regulatory limitations prior to use. For specific hazard
two-phase flow streams at pressures greater than 70 kPa gauge
statements, see Section 7.
(10 psig) and having a volumetric vapor fraction of at least
20 %. This practice is not applicable to single-phase flow
2. Referenced Documents
streams such as pumped liquid discharges at pressures above
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2.1 ASTM Standards:
E947 Specification for Sampling Single-Phase Geothermal
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This practice is under the jurisdiction of ASTM Committee E44 on Solar,
Liquid or Steam for Purposes of Chemical Analysis
Geothermal and OtherAlternative Energy Sources and is the direct responsibility of
SubcommitteeE44.15onGeothermalFieldDevelopment,UtilizationandMaterials.
Current edition approved March 1, 2004. Published June 2004. Originally
published as E1675 – 95. Last previous edition E1675 – 95. DOI: 10.1520/E1675-
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04E01. Annual Book of ASTM Standards, Vol 12.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E1675 − 04
2.2 Other Document: phase stratificati
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