University Of Tulsa
600 South College
Tulsa, OK 74104
3:30 p.m. Friday, March 9, 2012
On Campus | Alumni
Please join us in Keplinger Hall (room #M2) at 3:30 p.m. Friday, March 2, 2012 for the McDougall School of Petroleum Engineering's Graduate Seminar on "Integrated Study of the Liberty South Yegua Field - Modeling and Waterflood Evaluation" by Jose Severino of Cimarex Energy.
Jose Severino, is a Senior Reservoir Engineer with Cimarex Energy Co. in Tulsa, Oklahoma, and has served in this capacity for the last 6 years. He received his B.Sc. and M.Sc. degrees in Petroleum Engineering from The University of Tulsa in 2001 and 2007 respectively. Severino worked for Petróleos de Venezuela, S.A. (PDVSA) for almost 12 years where he was involved in the turnaround of large oilfield facilities, including rigs, gas processing plants, and refineries. He served his last years at PDVSA as reservoir development engineer for the Lagomedio assets, offshore Lake Maracaibo. He later joined Vintage Petroleum (now OXY) in 2005, also as reservoir engineer responsible for the East Texas, Oklahoma and Louisiana assets. Severino has conducted research in the areas of multiphase flow transport phenomena and multiphase compact separation with the Tulsa University Separation Technology Projects (TUSTP), more specifically in the modeling and developing of hydrocyclone technology for solid-liquid separation. He has publications in these areas in both the American Society of Mechanical Engineers (ASME) and SPE. His main areas of interest include integrated oilfield studies, reservoir simulation, and waterflooding. He is also interested in the development and deployment of compact separation systems for oilfield applications. Severino is member of the Society of Petroleum Engineers (SPE), and the honor societies of Pi Epsilon Tau and Phi Kappa Phi.
Integrated Study of the Liberty South Yegua Field - Modeling and Waterflood Evaluation
The Liberty South Yegua Field (LSYF) is a piercement-type salt dome feature located in the upper Texas Gulf Coast region. These geologic features have been prolific producers of hydrocarbons in this area, mainly from the Miocene, Frio, Vicksburg, Wilcox, Cook Mountain, and Yegua sands. Field production comes from the upper members of the Eocene Yegua formation, mainly from the EY-3. This sandstone formation is considered a good waterflooding candidate and is the subject of this study. The main objective of this engineering evaluation is the integrated characterization of the field and the practical assessment of its waterflooding potential. There is a great amount of static and dynamic data available for this study, including geologic, seismic, core, fluid, pressure and primary production performance.
Salt tectonics significantly influenced Yegua deposition and compartmentalized larger accumulations into smaller sub-basins, like the LSYF operated by Cimarex. This field is located in near Dayton, in Liberty County, Texas. The field extends for approximately 470 acres comprising multiple units in the Kate Dishman and Hartel leases. A total of ten wells have been drilled in this field to date, two of which are currently inactive due to high water production. The discovery well was the Kate Dishman #1 (KD #1) completed in January, 2006. Total oil and gas cumulative production through June 2011 are 1,482 MSTBo [thousand stock-tank barrels of oil] and 1,234 MMCF [million cubic feet] of gas from both EY-1 and EY-3. Fieldwide primary estimated ultimate recovery (EUR) are 1,807 MSTBo and 1,485 MMCFg respectively, effective as of June 1, 2011. One of shut-in wells, located nearest to the water-oil contact (KD #6) could be converted to water injection. Water supply is available from the shallower prolific Frio Sands, which are behind pipe in the KD #7, currently shut-in.
The primary injection objective (EY-3) is of excellent quality and is oil-bearing from -9,000 to -9,380 ft SS. Petrophysical evaluation shows an average net pay of 35.7 ft and weighted average effective porosity and initial water saturation of 26.4% and 42.8% respectively. The average effective oil permeability is 77 mD, and as high as 173 mD at initial water saturation and 2,800 psig net confining stress.
Evidence shows that the LSYF can greatly benefit from a secondary recovery project. According to reservoir modeling, waterflooding can enhance field recovery by at least an additional 1.2 MMSTBo [million stock-tank barrels of oil] of secondary oil, while also accelerating remaining primary reserves. Total Oil Originally in Place (OOIP) is 10.3 MMSTBo and total estimated primary EUR is 1.8 MMSTBo. The anticipated ultimate secondary recovery represents an additional 12% of the total OOIP. Total gross ultimate recovery is anticipated to be at least 3.0 MMBO, or 29.5% of the OOIP.
The developed modeling tool allows for the assessment of different injection scenarios and provides much needed flexibility to manage field production and the proposed waterflooding project implementation. With current reservoir pressures being well below bubble point and continuing to decline, modeling results show that it is critical to start water injection as soon as possible. EY-3 reached the bubble point pressure of 2,665 psia in May, 2007. Primary recovery factors of 17.7% are also consistent with those of solution gas-drive reservoirs. Aquifer support is very limited in EY-3 due to extensive faulting. Fieldwide pressure testing communication though, suggests that there is good sand continuity among existing wells. Also according to the modeling work, it seems that the drilling of additional production or injection locations will not be necessary. Detailed field characterization and modeling results are further addressed in this report.
Prof. Ovadia Shoham