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Title: Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs

Abstract

Large-scale water injection at The Geysers, California, hasgenerated substantial benefits in terms of sustaining reservoir pressuresand production rates, as well as improving steam composition by reducingthe content of non-condensible gases (NCGs). Two effects have beenrecognized and discussed in the literature as contributing to improvedsteam composition, (1) boiling of injectate provides a source of "clean"steam to production wells, and (2) pressurization effects induced byboiling of injected water reduce upflow of native steam with large NCGconcentrations from depth. In this paper we focus on a possibleadditional effect that could reduce NCGs in produced steam by dissolutionin a condensed aqueous phase.Boiling of injectate causes pressurizationeffects that will fairly rapidly migrate outward, away from the injectionpoint. Pressure increases will cause an increase in the saturation ofcondensed phase due to vapor adsorption on mineral surfaces, andcapillary condensation in small pores. NCGs will dissolve in theadditional condensed phase which, depending upon their solubility, mayreduce NCG concentrations in residual steam.We have analyzed thepartitioning of HCl between vapor and aqueous phases, and have performednumerical simulations of injection into superheated vapor zones. Oursimulations provide evidence that dissolution in the condensed phase canindeed reduce NCG concentrations in produced steam.

Authors:
; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE. Office of the Chief Financial Officer. Cost ofReimbursable and Cooperative Work - Non-Federal Entities
OSTI Identifier:
928235
Report Number(s):
LBNL-62376
R&D Project: G3W027PRUESS; BnR: 600303000; TRN: US200815%%797
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: Thirty-Second Workshop on Geothermal ReservoirEngineering, Stanford, CA, 22-24 January 2007
Country of Publication:
United States
Language:
English
Subject:
54; ADSORPTION; BOILING; CALIFORNIA; DISSOLUTION; GASES; PRESSURIZATION; PRODUCTION; RESERVOIR ENGINEERING; RESERVOIR PRESSURE; SATURATION; SOLUBILITY; STEAM; WATER

Citation Formats

Pruess, Karsten, Spycher, Nicolas, and Kneafsey, Timothy J. Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs. United States: N. p., 2007. Web.
Pruess, Karsten, Spycher, Nicolas, & Kneafsey, Timothy J. Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs. United States.
Pruess, Karsten, Spycher, Nicolas, and Kneafsey, Timothy J. Mon . "Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs". United States. doi:. https://www.osti.gov/servlets/purl/928235.
@article{osti_928235,
title = {Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs},
author = {Pruess, Karsten and Spycher, Nicolas and Kneafsey, Timothy J.},
abstractNote = {Large-scale water injection at The Geysers, California, hasgenerated substantial benefits in terms of sustaining reservoir pressuresand production rates, as well as improving steam composition by reducingthe content of non-condensible gases (NCGs). Two effects have beenrecognized and discussed in the literature as contributing to improvedsteam composition, (1) boiling of injectate provides a source of "clean"steam to production wells, and (2) pressurization effects induced byboiling of injected water reduce upflow of native steam with large NCGconcentrations from depth. In this paper we focus on a possibleadditional effect that could reduce NCGs in produced steam by dissolutionin a condensed aqueous phase.Boiling of injectate causes pressurizationeffects that will fairly rapidly migrate outward, away from the injectionpoint. Pressure increases will cause an increase in the saturation ofcondensed phase due to vapor adsorption on mineral surfaces, andcapillary condensation in small pores. NCGs will dissolve in theadditional condensed phase which, depending upon their solubility, mayreduce NCG concentrations in residual steam.We have analyzed thepartitioning of HCl between vapor and aqueous phases, and have performednumerical simulations of injection into superheated vapor zones. Oursimulations provide evidence that dissolution in the condensed phase canindeed reduce NCG concentrations in produced steam.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 08 00:00:00 EST 2007},
month = {Mon Jan 08 00:00:00 EST 2007}
}

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  • A mathematical model is developed for fluid and heat flow in two-phase geothermal reservoirs containing non-condensible gas (CO{sub 2}). Vertical profiles of temperature, pressures and phase saturations in steady-state conditions are obtained by numerically integrating the coupled ordinary differential equations describing conservation of water, CO{sub 2}, and energy. Solutions including binary diffusion effects in the gas phase are generated for cases with net mass throughflow as well as for balanced liquid-vapor counterflow. Calculated examples illustrate some fundamental characteristics of two-phase heat transmission systems with non-condensible gas.
  • A mathematical model is developed for fluid and heat flow in two-phase geothermal reservoirs containing non-condensible gas (CO{sub 2}). Vertical profiles of temperature, pressures and phase saturations in steady-state conditions are obtained by numerically integrating the coupled ordinary differential equations describing conservation of water, CO{sub 2}, and energy. Solutions including binary diffusion effects in the gas phase are generated for cases with net mass throughflow as well as for balanced liquid-vapor counterflow. Calculated examples illustrate some fundamental characteristics of two-phase heat transmission systems with non-condensible gas. 14 refs., 3 figs.
  • Explosive interactions between molten aluminum and water are being studied with a focus on fundamentals to determine what causes robust-enough triggers for explosion onset, to determine the extent of protection provided from various coatings and to develop a fundamentally-based simple, cost-effective novel methodology for prevention. The workscope includes experimentation and mathematical modeling of the interactions between molten metals and water at various different coated and uncoated surfaces. Phenomenological issues related to surface wettability, gas generation from coatings, charring of coatings, inertial constraint, melt temperature, water temperature, external shocks are being investigated systematically to gage their relative impact on the triggerabilitymore » of surface-assisted steam explosions. The steam explosion triggering studies (SETS) facility was designed and constructed as a rapid-turnaround, cost-effective, and safe means to address these phenomenological issues. Data from SETS tests have indicated that, non-condensible gas (NCG) generation during paint pyrolysis plays a predominant role in explosion prevention. This paper describes results of studies on impact of deliberate NCG injection on explosion prevention, via molten melt drops free-falling into water, as well as from tests using the SETS facility for studying entrapment induced explosive boiling. SETS is also being used to obtain information on time-varying and integral amounts of NCGs generated from various paints. Relevant data are presented. Results of investigations, taken together provide compelling evidence on the positive role NCGs play on explosion prevention.« less
  • Water injection into vapor-dominated reservoirs is a means of condensate disposal, as well as a reservoir management tool for enhancing energy recovery and reservoir life. We review different approaches to modeling the complex fluid and heat flow processes during injection into vapor-dominated systems. Vapor pressure lowering, grid orientation effects, and physical dispersion of injection plumes from reservoir heterogeneity are important considerations for a realistic modeling of injection effects. An example of detailed three-dimensional modeling of injection experiments at The Geysers is given.
  • Water injection into a vapor-dominated geothermal reservoir is an effective method of sustaining steam production from the field. Injection puts additional water to the reservoir and raises the prevailing reservoir pressure. This process improves the field`s productivity. However, the increased pressure also increases the water retention capacity of the reservoir rocks through the effects of adsorption and capillary condensation. Due to the significant costs associated with water injection programs, optimizing injection not only involves maximizing the energy yield from the resource but also the present worth of the project. Two crucial parameters that need to be established are: (1) howmore » much to inject; and, (2) when to inject it. This study investigated the optimal design of these parameters. It was found that comparable energy yield can be attained for injection programs that are initiated at various stages of the field`s development. Higher injection rates are desirable when the injection program starts later in the productive life of the field. Considering the economics of the project, it is best to implement the injection program during the later stages of the field`s development. This way, a greater fraction of the injectate can become available for production and at the same time optimize the present worth of the project.« less