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The Empire Abo field, located in New Mexico, US, covers 11,000 acres (12.5 miles long by 1.5 miles wide) and contains approximately 380 millionstock tank barrels (STB) of original oil in place (OOIP).[1][2] This reservoir is a dolomitized reef structure (Figure 1) with a dip angle of 10 to 20 from the crest toward the fore reef. The oil column is approximately 900 ft thick, but the average net pay is only 151 ft thick. The pore system of this reservoir is a network ofvugs, fractures, and fissures because the primary pore system has been so altered by dolomitization; the average log-calculated porosity was 6.4% BV. Numerical simulations of field performance and routine core analysis data have indicated that the horizontal and vertical permeabilities are about equal.
- North America > United States > Texas (0.76)
- Africa > Nigeria > Gulf of Guinea > Niger Delta (0.71)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (22 more...)
- Reservoir Description and Dynamics > Reserves Evaluation > Estimates of resource in place (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management (0.92)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (0.77)
- Information Technology > Knowledge Management (0.42)
- Information Technology > Communications > Collaboration (0.42)
Evaluation of Fracture Stimulation Treatments by Integrated Reservoir Description and Fracture Treatment Analysis in the Pecos Slope Abo Tight-Gas Reservoir, Southeastern New Mexico
Sanchez, Steve (New Mexico Institute of Mining and Technology) | Engler, Thomas W. (New Mexico Institute of Mining and Technology) | Kelly, Mike (New Mexico Institute of Mining and Technology)
Abstract The primary goal of this study was to couple reservoir characterization of the Abo Formation with hydraulic fracture analysis and subsequently, to infer infill drilling potential. Two detailed case studies were investigated to reevaluate original hydraulic fracture treatment designs, to compare and evaluate fracture parameters, and to determine if the fracture treatments were providing sufficient reservoir stimulation. Approximately 80 wells were studied in the southern part of the Pecos Slope Abo Field. Decline curve analysis was performed on all wells by a modified set of Fetkovich type curves. Analysis of this work show linear to near-linear flow in most cases with permeability values less than 0.1 md and variations in reservoir properties as is typically observed in low permeability reservoirs. These variations resulted in difficulty in evaluating infill drilling potential. Evaluation of fracture stimulation treatments was accomplished by matching recorded surface treating pressure with a fracture propagation model. Unusually high initiation pressures were observed in the case study wells; initial stress state, vertical fracture growth, fracture toughness, perforation restrictions, and the development of multiple fractures in a single, bounded layer were evaluated as possible causes for the high initiation pressures. Results from this work showed the multiple fractures model providing the best match for the two wells. Fracture length varied from approximately 1150 ft to 750 ft with a single fracture model and was reduced by approximately 10 to 30% for each additional fracture added. The fracture data was input into a fractured well performance model, which was used to match the production rate and therefore verify the process. The integration of decline curve analysis and fracture analysis provided better descriptions of reservoir properties and more accurate designs of fracture propagation models. This combined approach also improved evaluation of infill drilling potential by evaluating reservoir properties and stimulation. Background The Pecos Slope Abo Field is located in southeastern New Mexico in north central Chaves County, directly north and east of the City of Roswell (see Figure 1). The producing area of the Abo formation is located on the northwestern part of the northwest shelf of the Delaware Basin. The structure is a gently eastward-dipping homocline, which occurs over the entire producing area. The depositional facies of the Abo were influenced by the positive and negative features of the rise of the Pedernal highlands to the west, which had a marked effect on sedimentation during the late Pennsylvanian and early Permian. The upper lithologic unit is approximately 600 ft thick and is composed of interbedded mudstones and lenticular sandstones; deposited in a fluvial deltaic system. The gas-bearing sandstones are very fine-grained, arkosic and hematitic. The Pecos Slope Abo Field was originally discovered in June of 1977 but development did not escalate until the early 1980's. In May of 1981 the Abo Formation was designated, as a tight gas formation. As a result of the tight gas designation, the Abo Formation became the leading target for natural gas in New Mexico in late 1981. The well spacing was restricted in the past to 320-acres but currently is 160-acres. Well spacing is reduced in order to increase the drainage area and improve recovery. Currently over 800 wells have been drilled in the Pecos Slope Field.
- North America > United States > New Mexico > Chaves County (0.68)
- Africa > Nigeria > Gulf of Guinea > Niger Delta (0.64)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.67)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.55)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment > Fluvial Environment (0.54)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (25 more...)
Abstract Yates Petroleum has developed successful drilling and completion practices through experience with 200 wells in the Pecos Slope Abo gas field. several methods have been used for estimating ultimate reserves from the wells in this low permeability reservoir. The most promising is a drawdown analysis that matches promising is a drawdown analysis that matches computerized type curves with data on daily flow rates and tubing pressure. Introduction The Pecos Slope Abo gas field was discovered in June of 1977 when Yates Petroleum re-entered the Honolulu McConkey #1 in Section 10-9S-26E of Chaves County, New Mexico. By the end of 1979, only one well had been connected to a pipeline. Twenty more wells began production in 1980. Development began in production in 1980. Development began in earnest after May of 1981 when the Abo formation was designated as a tight gas formation under Section 107 TF of the Natural Gas Policy Act. This designation covered 1.54 million acres in Chaves and DeBaca counties (Figure 1). By September of 1982, 292 wells were producing an average of 73.5 MMcf/D or about 252 Mcf/D per well. The two principal operators are Yates Petroleum with 114 producing wells and Mesa Petroleum with 114 producing wells and Mesa Petroleum with 91. Petroleum with 91.In May of 1982, Yates and ANR Production applied for tight sand designation for 5.1 million additional acres to the west and north of the approved tight gas area. About 15 wildcats have been drilled in this extension area (Figure 1) and several wells have been completed as small producers. In addition, about 150 wells within the original field are waiting on pipeline connection. Many of these are scheduled to be connected in the Fall 1982. The Abo sandstone is a siltstone consisting of quartz, feldspar and mica, cemented with calcite and clays. The reservoir rock is known informally as a "red bed" section. These silty sandstones were probably deposited by a river system, flowing generally from the northwest to the southeast during Permian Time. Productive zones in the main portion of the field occur at depths between about 3500 and 5000 feet. Permeability estimates in the producing zones normally average between 0.03 and 0.05 md. The reservoirs are underpressured with average bottom-hole pressure of 1125 psig. Table 1 shows the pressure of 1125 psig. Table 1 shows the composition of the sweet gas produced. The wells now produce into a pipeline pressure of 200 psia. The purchaser has contracted to reduce the pipeline pressure further to 150 psia in the future. The purpose of the paper is to describe how Yates Petroleum drills and completes a well in the Pecos Slope Abo field and then estimates reserves. DRILLING PRACTICES Total depth of a typical well in the developed portion of the field is 4200 ft. Two or three strings of casing are required depending on the severity of lost circulation problems in the basal San Andres. The well problems in the basal San Andres. The well is spudded with fresh water gel, and surface casing is set at the top of the Slaughter zone at 300 to 900 ft. The New Mexico oil Conservation Division requires that cement be circulated behind this string of casing to protect the fresh water. Normally, 40.5#, protect the fresh water. Normally, 40.5#, 10 ¾" J-55 is used but 8 5/8" casing can be substituted if there is no chance problems further downhole. problems further downhole.
- Africa > Nigeria > Gulf of Guinea > Niger Delta (0.25)
- North America > United States > Hawaii > Honolulu County > Honolulu (0.24)
- North America > United States > New Mexico > Chaves County (0.24)
- Geology > Mineral > Silicate > Tectosilicate (0.54)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.44)
- Well Drilling > Drilling Operations (1.00)
- Well Completion > Completion Installation and Operations (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- (3 more...)