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Sempra Energy’s Energía Costa Azul LNG (ECA LNG) subsidiary reached a final investment decision (FID) to build its $2-billion Phase 1 natural gas liquefaction export project in Baja California, Mexico. ECA LNG, a joint venture between Sempra LNG and its Mexico subsidiary IEnova, is the only LNG export project to reach FID in 2020, and is slated to be the first on the Pacific Coast of North America. The facility will connect natural gas supply from Texas and the western US to Mexico and other countries across the Pacific Basin. First production from Phase 1 is expected in late 2024. The company secured a 20-year supply agreement with Mitsui and an affiliate of Total for the purchase of 2.5 mtpa and is working with Total for a potential equity investment in the facility.
Mexico, the world’s fourth largest producer of geothermal energy, generates 965 MW of electricity. One field alone produces 195 MW. However, to maximize the steam production of geothermal wells it is often necessary to perform matrix stimulation treatments. The temperature and mineralogy of the naturally fractured volcanic formations and scales tendency present some unique challenges.
The potential of many geothermal wells is limited by formation damage. Drilling fluid invasion, fines migration, silica plugging, and scaling being the most common. Mineral scale deposition occurs in the wellbore or in the natural fractures through which water is either injected or produced. In producing wells, the composition of scale is dependent on the mineralogy of the metamorphic formation. In injection wells, the scale is dependent on the composition of the injected water. With limited information regarding the mineralogy of the scale and the formation, many conventional matrix treatments are unsuccessful.
A hybrid design methodology, combining sandstone and carbonate acidizing techniques has proved to be the first step to successfully treating Mexico’s and Central America’s geothermal wells The treatments are then further customized for each field to optimize productivity and injectivity. The final fluid composition is often very different from that used in conventional treatments due to different selection criteria and placement techniques.
Identifying and understanding this concept has helped producers in Mexico and Central America increase their energy production per well by an average of 65%. While in some cases energy production has increased 300%.
The hybrid design methodology has been successfully used to stimulate more than 50 geothermal wells in Mexico and Central America - Humeros (Puebla), Tres Virgenes (Baja California), Berlin (El Salvador), San Jacinto (Nicaragua) and Azufre’s (Michoacan). The results of these campaigns demonstrate that it is possible to consistently improve the productivity of geothermal wells through the correct treatment.
Turbidite channels are important hydrocarbon reservoir types but difficult to predict due to their complex internal architectures and highly variable facies. This study use forward modeling of outcrop data to improve the knowledge of seismic features of deep water slope channel systems. The well-exposed, late Cretaceous San Fernando slope channel system in Baja California, Mexico provides a great opportunity to analyze the internal architecture and lithofacies variation at unprecedented scales. Comprehensive outcrop data were utilized to construct a detailed geological model that includes lateral and vertical architecture and lithology changes over 250m vertically and 2500m horizontally - substantially larger than any previously reported in literature. Physical property data were extracted from various subsurface locations and a range of depths. Ranges of properties for the same lithologies at different burial depths were adopted to account for the effects of compaction and cementation. The synthetic seismograms were generated through finite-difference elastic forward modelling methods; they illustrate seismic responses of different typical slope channel lithofacies associations at different resolution, and the effect of physical property variation on seismic expression.
Corrosion affects the durability of the civil infrastructure assets, including the water production, supply and storage systems. Green corrosion inhibitors, to prevent and protect against corrosion, will extend the life of the water industrial equipment. This inhibitors pertain to the advanced field of "Green Chemistry" also known as sustainable chemistry. They are classified as anodic, cathodic or mixed types depending on their protection mechanism. Special green inhibitors are obtained from plants growing in desertic regions of The State of Baja California, Mexico, by ethanolic and aqueous extraction.
Because many fundamental questions concerning the dynamics of the Earth and itsstructure remain unanswered, the Integrated Ocean Drilling Program (IODP) hasrecently completed a feasibility study for drilling and coring a hole 500meters (1,640 feet) through the Mohorovicic seismic discontinuity into theupper mantle of the oceanic crust from three candidate locations in the PacificOcean (Cocos Plate, Baja California, and offshore Hawaii).
The main challenges discussed in this paper are threefold. First, drilling withriser in ultra-deepwater environments with water depths around 4,000 meters(13,120 feet) which will set a new world record. Secondly, drilling and coringin very high temperature igneous rocks with bottom-hole temperatures that areestimated to be as high as 250°C (480°F). Finally, drilling and coring a verydeep hole with a total drilled and/or cored interval around 6,000 meters(19,685 feet) in the oceanic crust below the Pacific Ocean seafloor in order toreach the upper mantle which will constitute a major achievement for theworldwide scientific community.
This paper presents detailed analyses and several discussions concerning marinedrilling riser options by first reviewing the capabilities of the current riserconfiguration that is onboard the IODP scientific drilling drill-ship Chikyuand then evaluating alternative designs such as titanium riser, hybridtitanium-steel riser, slim-riser and lighter buoyancy modules. Furthermore, thedeepwater subsea equipment, drill-pipe design, wellbore design, down-holetools, drilling fluids, circulating temperature, cementing methods and variousadvanced technologies that would be required for this type of operation arealso reviewed. In addition, operational time and cost estimations for differentscientific drilling cases are provided (borehole continuously cored to totaldepth, continuous cores only across the major lithologic and geophysicaltransition intervals, spot coring and when only the mantle section iscored).
Finally, this study helps evaluate critical issues in terms of current andtrending technologies in oilfield and geothermal industries that need to beresolved before embarking upon such a challenging project. The results of thiswork show that drilling to the mantle is certainly feasible, and that there areexisting solutions to many of the technological challenges based on work beingdone in the oilfield, offshore and geothermal industries.
la Escalera, L.M. Martinez de (Corrosion y Proteccion Ingenieria, S.C. ) | Paredes, M. (Corrosion y Proteccion Ingenieria, S.C. ) | Rios, A. (Aeropuertos y Servicios Auxiliares ) | Lopez-Mendez, J.A. Padilla (Soluciones Para Mantenimiento, C.A. ) | Genesca, J. (Universidad Nacional Autonoma de Mexico ) | Ascencio, J.A. (Universidad Nacional Autonoma de Mexico ) | Gomez, L. Martinez (Universidad Nacional Autonoma de Mexico )
Speaking for myself and on behalf of Mr. Ignacio Pichardo, the Secretary ofEnergy, I would like to extend to you a warm welcome to Mexico and to thisbeautiful and historical city of Villahermosa, Tabasco.
As you probably know, the natural gas industry in Mexico was managed andoperated by the State with very limited access to the private sector. What thismeant was that there was neither private ownership of pipelines nordistribution systems, very limited private investment and restrictions on freetrade of the commodity.
As of June, 1995, we have new regulations regarding transportation, storage,and distribution of natural gas with private ownership of pipelines anddistribution systems explicitly allowed. There are no longer any restrictionson imports of natural gas, thus ending the Petroleos Mexicanos monopoly in thisparticular area.
These actions will promote the use of natural gas, build and expand itsmarkets, encourage and facilitate private investment in the industry and, also,create a competitive market-driven environment.
On the consumer side, the choices for cleaner fuels, the quality of serviceand environmental well-being will be enhanced. Also, the use of natural gasdecreases the amount of certain pollutants in the air even though it createssome problems promoting the increment of COx emissions and the so-called"green-house" effect.
We have talked about some of the good things happening in the natural gassector. Now, we will give you an idea of the amount of reserves and uses ofnatural gas in Mexico (Table 1).
The amount of natural gas in the total hydrocarbon reserves is 21%. In thelast ten years, we have incorporated natural gas reserves that are equivalentto approximately 45% of the amount produced; 86% of it is associated gas and isoriginated in the southern and marine regions.
Our natural gas contains a high percentage (20%) of liquids which are mostlyprocessed in cryogenic plants.
The amount of natural gas that will be supplied to the economy will increasedue to investments in the northeast area of Mexico, and in the Campeche-Tabascoregion. We expect an average production of approximately 4,280 million cubicfeet daily (MMCFD) for 1996; up to 4,200 MMCFD for 1997; 4,500 for 1999; 5,000for the year 2000. Production will peak in the year 2002 (5,600 MMCFD) droppingto about 4,500 by 2005.
On the demand side, starting on January 1st, 1998, we will be forced toincrease our gas consumption due to new environmental regulations. TheSecretaria de Energia has been working on several projections with differenteconomic scenarios and, in all of them, the percentage of natural gas useincreases from roughly 37% in 1995 to around 50% by 2005 in the industrialsector. Overall in total energy consumption, natural gas could increase itsparticipation from 23% in 1995 to close to 30% in 2005. This is a highersharing than that which Canada and the United States could have for natural gasin that year. According to our scenarios, the total amount of gas that theelectric utilities will use in 2005 comes to 1,660 MMCFD; the industrial andprivate consumption will average around 1,400 MMCFD and Pemex will consume1,500 MMCFD which brings the total demand of natural gas up to 4,560 MMCFD.
However, there are some ways to curve the total demand of gas through energysaving methods particularly where PEMEX is concerned. The total savings couldbe in the vicinity of 400 MMCFD.
After all of this statistical information, let me tell you about thedownstream opportunities of investment in Mexico. First of all, we will providesome information regarding the use of gas in the generation of electricity.
According to the Comision Federal de Electricidad (C.F.E.), we will requirean extra capacity of 9,031 Megawatts (Mw) by 2005. Of those, 6,965 Mw should beproduced by combined cycles. The power producing plants are going to be locatedin the states of Yucatan, Baja California, Chihuahua, Nuevo Leon, Tamaulipas,Queretaro, Durango, Sonora and Guanajuato (Table 2).
The Cerro Prieto geothermal field is located in Baja California, Mexico, in the, Salton Trough-a rift basin filled mainly with Colorado River sediments. A comprehensive wireline log analysis was undertaken as part of a multidisciplinary study of this geothermal system. It established (1) the physical properties of the various sedimentary units; (2) the depositional environment and hydrothermal alteration of the units; (3) the location, attitude, and displacement of faults; and (4) the subsurface circulation of the geothermal fluids. Presented are the methodology that was used and the application of the results to further exploration and development of this high-temperature geothermal resource.
The liquid-dominated Cerro Prieto geothermal field is located in the sediment-filled Mexicali Valley of Baja California, Mexico, about 20 miles [30 km] south of the U.S. border (Fig. 1). More than 100 deep exploration and development wells have been drilled in the area (Fig. 2), a few reaching crystalline basement. Analysis of the vast amount of data collected from these wells has given us a good understanding of the geologic characteristics of this high-temperature (up to 680F [360C]) geothermal resource. The exploration effort at Cerro Prieto is summarized in an earlier paper. paper. The purpose of this paper is to discuss the wireline log analysis that led to (1) the development of geologic and hydrogeologic models of the field, (2) an understanding of the depositional environment of some of the sedimentary units identified in the subsurface, and (3) the identification of postdepositional changes in these units. These studies have postdepositional changes in these units. These studies have allowed us to determine the variations in porosity, permeability, thickness, and lateral continuity of the permeable (and less permeable) layers in the system-crucial parameters for the design permeable) layers in the system-crucial parameters for the design of drilling and completion of new wells and for the development of a reservoir management plan.
Geologic Setting and Recent History of the Area
The Mexicali Valley is part of the Salton Trough, an actively developing structural depression that resulted from tectonic activity that has created a series of spreading centers and transform faults that link the East Pacific Rise to the San Andreas fault system. The Cerro Prieto field is associated with one of these spreading centers, where the crust is being pulled apart by right-lateral strikeslip movement along the Cerro Prieto and Imperial faults (Fig. 3). During the early Pliocene, the current configuration of the Gulf of California began to develop by major crustal extension, which split Baja California from the Mexican mainland. At that time, the waters of the Gulf of California extended northward to about the Salton Sea area. The progradation of the Colorado River delta into the Cerro Prieto area began in the mid- to late Pliocene. The southwesterly advance of the delta was essentially complete by the late Pliocene. This resulted in the conversion of the Salton basin to a nonmarine depositional basin. By the mid-Pleistocene, the marine connection between the Gulf of California to the south and the Imperial Valley to the north was severed.
Geologic and Hydrogeologic Models of Cerro Prieto
The subsurface stratigraphy at Cerro Prieto is characterized by vertical and lateral variations in lithofacies. The lithologic column consists of (1) an upper part of unconsolidated and semiconsolidated sediments (Unit A) that is mainly sands, silts, and clays, and (2) a lower part of consolidated sediments (Unit B) that is mainly sandstones and part of consolidated sediments (Unit B) that is mainly sandstones and shales. The hydrothermal alteration of the deeper layers and the existence of hydrothermal mineral zonation around the reservoir have been documented by careful mineralogic studies of well cuttings and cores and by analysis of wireline well logs. Following the general approach of Lyons and van de Kamp, Halfman et al. used wireline and lithologic log data to delineate and to classify the lithologic sequences penetrated by the wells into three lithofacies groups: sandstone, sandy shale, and shale (Figs. 4 and 5A). The sandstone beds basically (1) are thick, permeable, and well-defined (with some interbedded shales) in the sandstone group, (2) are thinner and less permeable (with a higher percentage of intercalated shales) in the sandy-shale group, and (3) are even thinner ( less than 10 ft [ less than 3 m]) in the shale group (e.g., Fig. 4). The main geophysical logs used to develop this model include gamma ray (GR), spontaneous potential (SP), deep induction (ILD), and compensated formation density (RHOB).
Noble, John E. (Lawrence Berkeley Laboratory, University of California) | Lippmann, Marcelo J. (Lawrence Berkeley Laboratory, University of California) | Witherspoon, Paul A. (Lawrence Berkeley Laboratory, University of California)
Noble, John E., Lippmann, Marcelo J., and Witherspoon, Paul A., Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720. Manon M., Alfredo, Comision Federal Electricidad, Coordinadora General Ejecutiva de Cerro Prieto, Mexicali B.C. Mexico.
The Lawrence Berkeley Laboratory and the Comision Federal de Electricidad of Mexico are conducting a joint investigation of the Cerro Prieto Geothermal Field, located approximately 35km south of Mexicali, Baja California, Mexico, in the Sea of Cortez-Salton Trough.
Recent analyses of various geophysical/electrical logs, temperature logs, production and geochemical data and the subsequently developed preliminary model of the structure of the geothermal system and the distribution of geothermal fluids are presented. Techniques routinely applied to petroleum exploration were successfully used in the development of a preliminary model of this water-dominated system.
Our study indicates the upwelling of geothermal fluids along an east bounding fault from a deep, as yet unexplored source. The fluids dissipate into various sand horizons at various depths. The resulting stratigraphic and fluid flow model is of importance in planning additional developments of the Cerro Prieto planning additional developments of the Cerro Prieto Geothermal Field.
The Imperial-Mexicali Valley is recognized as having a potential for large scale production of electrical power from geothermal resources to help satisfy the energy requirements of Southern California and the Mexican states of Sonora and Baja California, North. Estimates of the potential of the Imperial Valley, alone, range from 5000 to 10000 Mwe. Exploration has defined various geothermal prospects in the Imperial Valley, and consequently several areas are currently being evaluated, e.g.: Brawley, Heber, East Mesa, etc. (Figure 1).
In the Mexicali Valley, exploration for geothermal resources has concentrated south-southeast of the Cerro Prieto Volcano, over a 400 square km area approximately 35 km south of Mexicali, Baja California. This area is typified by numerous hot springs, mud volcanos, and fumaroles. The neighboring Sierra de los Cucapas, which lie to the west of Cerro Prieto, are the predominate structural feature of the area.
In 1959 exploration for geothermal resources began in this area with photo and field geologic surveys In the same year three shallow exploratory wells (M-1A, M-2, M-2A) were drilled to depths of 523 m, 755 m, and 403 m, respectively. Geophysical investigations were commenced in 1961 with gravimetric and resistivity surveys. These surveys were completed in 1963.
In 1964 four exploration wells (M-3, M-4, M-5, M-6) were drilled to depths of 2563 m, 2006 m, 1303 m, and 2040 m, respectively (Figure 3). Well M-3 penetrated Cretaceous Cucapas granodiorite basement at 2532 m. Well M-5 was a discovery well, and from 1966 to 1968, 14 production wells were drilled. The production from these wells, supplemented by production from four of the twelve wells drilled since 1972, supply separated steam to a 75 Mwe power plant. The total production is currently 750 tonne/hr separated steam (at 100 psig) and 2000 tonne/hr separated water. The separated water is piped to a brine waste pond; while in transit to the pond, the water flashes and vents to the pond as steam. Approximately 30 Mwe are lost to the waste pond, and development plans call for future pond, and development plans call for future installation of low-pressure turbines to utilize this energy source.
The Cerro Prieto power plant commenced operation in April, 1973. It was the first operational geothermal power plant in Latin America and the first liquiddominated geothermal system to produce commercial amounts of electricity in the Americas. The plant is currently being expanded to 150 Mwe, utilizing production from new and existing standby wells. Development production from new and existing standby wells. Development and exploration drilling are continuing, and a target of 400 Mwe has been set for 1982.
Comision Federal de Electricidad's (CFE) systematic exploration and development of the Cerro Prieto geothermal resource has resulted in a vast accumulation of data. These data provide a rare opportunity to conduct a case study of the exploitation of a geothermal system. In 1975, a working relationship was established between CFE and the Lawrence Berkeley Laboratory (LBL) to conduct such a study. In addition, LBL would become a repository for Cerro Prieto data in order to make such data available to the geothermal community.
This paper deals with the application of well-established pressure transient analysis techniques to the determination of geothermal reservoir parameters. Among the pressure transient techniques available, those concerned with two-rate flow testing were chosen. A two-rate test may permit obtaining data while reducing interruption of power generation. Two-rate techniques have been applied successfully to both oil and gas reservoirs; however, no data have been published to date--to the authors' knowledge--on the application of this method to liquid-dominated geothermal reservoirs. Data from one test run on a well in the Cerro Prieto Geothermal Field are shown. The field data were interpreted by means of four different models. Three of the models produced results that agreed with each other, the fourth one produced data scatter.
The Cerro Prieto Geothermal Field is located about 30 kilometers south of Mexicali, Baja California. As shown in Figure 1, this field is situated at the southern end of the Salton-Mexicali trough, which includes other thermal anomalies of great interest, such as Heber and East Mesa. The reservoir is a liquid-dominated system having a cap rock made of impervious plastic clays. This cap acts as a seal, keeping the hot water trapped and preventing the dissipation of heat to the surface. Figure 2 shows a schematic geological cross section of the reservoir drawn in an East-West direction. The permeable layers consist of alternating shale and permeable layers consist of alternating shale and sandstone layers resting on a highly fractured granitic basement. Basement rocks were encountered in one of the wells at a depth of approximately 2500 meters. The thickness of the cap rock varies, according to the location of the wells, from 700 up to almost 1000 meters in the portion of the field already drilled.
The first exploratory well in the area was drilled in 1961, and in 1964, four more exploratory wells were drilled. After an extensive field-test program, the Comision Federal de Electricidad program, the Comision Federal de Electricidad started the construction of a 75-MW geothermal power plant in 1968. The plant was located in the Mexicali plant in 1968. The plant was located in the Mexicali valley and named for the Cerro Prieto volcano. This plant started commercial operation in April 1973, and has been in operation since that date. The turbines operate on steam from 14 wells. The geothermal fluid is obtained as a water-vapor mixture, because flashing takes place at some depth inside the wellbore. The separated hot brine is disposed of in an evaporation pond; however, plans are being made to evaluate the feasibility of reinjecting at least part of the spent liquid.
Although well testing and pressure transient analysis techniques have been widely applied by petroleum engineers to gas and oil reservoirs (to petroleum engineers to gas and oil reservoirs (to find mean formation pressure, skin factor, and average permeability and porosity), the application of the permeability and porosity), the application of the same techniques to geothermal reservoirs encounters problems that are not commonly found in petroleum problems that are not commonly found in petroleum applications. In hot-water wells, two-phase flow and heat transfer influence the pressure response when the wells are shut-in. In addition to this, gathering of the data is difficult because of the high temperatures involved. Bottom-hole temperatures in the range of 300 to 320 degrees C are common in the Cerro Prieto Field. Until recently, there were no bottomhole pressure measuring devices that could withstand such temperatures for more than three hours. Another problem is mechanical damage due to extreme buffeting problem is mechanical damage due to extreme buffeting by the high production rates of boiling geothermal fluids. Rates in excess of 24,000 B/D are common.
Considering these facts, it was decided that the best choice for obtaining pressure-time data by means of standard bourdon-tube type pressure bombs would be short-time duration drawdown tests. These tests could be run by changing the flow rate to some predetermined value after the well was stabilized at a predetermined value after the well was stabilized at a given constant rate for some time. This type of test is known in petroleum technology as a "two-rate" flow test. It was first proposed by Russell in 1962. Further improvements in this technique were introduced by Selim and Odeh and Jones.