skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Simulations studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field

Abstract

Well AH-4{sub bis} at the Ahuachapan Geothermal Field is planned to be drilled on the same pad as the former AH-4. A simulation study was carried out for two casing diameters 13 5/8 and 9 5/8 inches in order to estimate its production and to know its economic feasibility. The simulation results indicate a high probability of production in the range of 7 Mwe, equivalent to 120 kg/s total mass flow rate, 1250 kJ/kg at 6 bar-a for the new well AH-4b{sub bis}. Well AH-17 is good producer, during 1991 after ten years of production, the well was shut-in due to silica scaling problems. A wellbore simulation was carried out in order to predict the new production conditions after the work-over, mainly to estimate the water flow rate in order to reduce the silica scaling. The results indicate a very low water flow rate. The match between the simulated and measured production curves after the work-over was successful. The well AH-18 is located at the southern part of the actual bore field. CEL is planning to expand the borefield at this area and it is necessary to estimate the possible production conditions at that zone. The results indicate a highmore » probability of production at that area. The power potential is estimated at 3.5 Mwe per well at WHP 6 bar-a and the wells will not require induction.« less

Authors:
 [1]
  1. Recursos Geotermicos Comision Ejecutiva Hidroelectrica del Rio Lempa CEL, San Salvador (El Salvador)
Publication Date:
OSTI Identifier:
472064
Report Number(s):
CONF-960124-
TRN: 96:005767-0015
Resource Type:
Conference
Resource Relation:
Conference: 21. Stanford workshop on geothermal reservoir engineering, Stanford, CA (United States), 22-24 Jan 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the twenty-first workshop on geothermal reservoir engineering; PB: 595 p.
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; AHUACHAPAN GEOTHERMAL FIELD; RESERVOIR ENGINEERING; GEOLOGIC MODELS; WELL DRILLING; EL SALVADOR; GEOTHERMAL RESOURCES

Citation Formats

Monterrosa, M.E. Simulations studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field. United States: N. p., 1996. Web.
Monterrosa, M.E. Simulations studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field. United States.
Monterrosa, M.E. 1996. "Simulations studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field". United States. doi:.
@article{osti_472064,
title = {Simulations studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field},
author = {Monterrosa, M.E.},
abstractNote = {Well AH-4{sub bis} at the Ahuachapan Geothermal Field is planned to be drilled on the same pad as the former AH-4. A simulation study was carried out for two casing diameters 13 5/8 and 9 5/8 inches in order to estimate its production and to know its economic feasibility. The simulation results indicate a high probability of production in the range of 7 Mwe, equivalent to 120 kg/s total mass flow rate, 1250 kJ/kg at 6 bar-a for the new well AH-4b{sub bis}. Well AH-17 is good producer, during 1991 after ten years of production, the well was shut-in due to silica scaling problems. A wellbore simulation was carried out in order to predict the new production conditions after the work-over, mainly to estimate the water flow rate in order to reduce the silica scaling. The results indicate a very low water flow rate. The match between the simulated and measured production curves after the work-over was successful. The well AH-18 is located at the southern part of the actual bore field. CEL is planning to expand the borefield at this area and it is necessary to estimate the possible production conditions at that zone. The results indicate a high probability of production at that area. The power potential is estimated at 3.5 Mwe per well at WHP 6 bar-a and the wells will not require induction.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1996,
month =
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Well AH-4 bis, at the Ahuachapan Geothermal Field is planned to be drilled on the same pad as the former AH-4. A simulation study was carried out for two casing dameters 13 5/8 and 9 5/8” in order to estimate its production and to know its economic feasibility. The simulation results indcate a high probability of production in the range of 7 Mwe, equivalent to 120 kg/s total mass flow rate, 1250 kJ/kg at 6 bar-a for the new well AH-4 bis. Well AH- 17 is good producer, during 1991 after ten years of production, the well was shut-in duemore » to silica scaling problems. A wellbore simulation was carried out in order to predict the new production conditions after the work-over, mainly to estimate the water flow rate in order to reduce the silica scaling. The results indicate a very low water flow rate. The match between the simulated and measured production curves after the work-over was successful. The well AH-18 is located at the southern part of the actual bore field. CEL is planning to expand the borefield at this area and it is neccessary to estimate the possible production condtions at that zone. The results indicate a high probabilty of production at that area. The power potential is estimated at 3.5 Mwe per well at WHP 6 bar-a and the wells will not require induction.« less
  • Modeling studies of Ahuachapan include analyses of interference test data, modeling of the fieldwide pressure decline and the development of a three-dimensional natural state model of the field. The main objective of this work is to obtain reasonable estimates for the transmissivity and storativity of the reservoir and to investigate fluid and heat flow patterns in the system. The analyses of the interference test data and the long term pressure decline data indicate that the average reservoir transmissivity is about 30 Dm and the storativity about 3.5 {times} 10{sup {minus}6} m/Pa. The natural state modeling supports an overall average transmissivitymore » of 25--35 Dm and indicates that the system is recharged with 255{degree}C hot water at a rate of about 225 kg/s. The total thermal throughflow for the Ahuachapan system is estimated to be about 250 MW{sub t}. 10 refs., 11 figs., 3 tabs.« less
  • A hydrogeological model of the Ahuachapan geothermal field has been developed. It considers the lithology and structural features of the area and discerns their impact on the movement of cold and hot fluids in the system. Three aquifers were identified, their zones of mixing and flow patterns were obtained on the basis of temperature and geochemical data from wells and surface manifestations. 12 refs., 9 figs.
  • Well logging operations were performed in eight of the geothermal wells at Ahucachapan. A series of high temperature instruments, including temperature/rabbit, caliper, fluid velocity/temperature/pressure (STP) and fluid sampler were deployed in each well. The caliper tool was used primarily to determine the possible chemical desposit buildup in the casing or liner, and in one well to investigate a suspected break in the casing. STP logs were obtained from six of the eight wells at various flow rates ranging from 30 to 70 kg/s. A static STP log was also run with the wells shut in to provide data to bemore » used in the thermodynamic analysis of several production wells. 23 refs., 1 tab.« less
  • The present exploitation conditions of the Ahuachapan field are discussed. The high well density in a small area has resulted in a significant reservoir pressure decrease due to the inherent reservoir over-exploitation. The average pressure in the exploitation zone has decreased from the 1975 value of 34 kg/cm{sup 2} to the May 1983 value of 23 kg/cm{sup 2}. The production decline characteristics of the Ahuachapan wells were examined, concluding that all wells but Ah-22 show exponential decline. The cumulative production-reinjection for the field up to April 1983 is 159.090 x 10{sup 6} tons, and 37.592 x 10{sup 6} tons, respectively.more » The effect of reinjection upon field behavior is evident when observing the pressure decline characteristics of the field. It is seen that for indection fraction related to total mass extracted above 30 percent, the average decline pressure in the production area becomes approximately stabilized. If this condition is not met the reservoir pressure decreases sharply. From this finding it is concluded that a careful and properly planned reinjection program is a must for the field. The observed temperature reduction in some of the wells seems to be the result of two operating mechanisms. First, we have the pressure decline that produces water vaporization and the consequent temperature descend. Analysis of information available shows no clear indication of deleterious temperature effects on the producing wells due to injection. The only exception observed to date is well Ah-5 that because its close distance and its relative structural position and direct hydraulic connection to injector Ah-29, presented conditions for fast displacement of the thermal front, resulting in unsufficient contact area and residence time for reheating of the injected water.« less