Sarita







		Located in Kenedy County, Texas, the East Sarita field produced from stacked Frio abnormally pressured sands from 11500'-15000'. Initial production was established in 1967 from the Sarita B-14 and the fields have since achieved a cumulative production of 90 BCF. Production was about 3 MMCFD when the fields were purchased from Exxon in 1994. Rates were increased by identifying and developing behind-pipe reserves. A field study defined development locations and it was expected that significant reserve additions would be achieved through the application of 3D seismic and drilling. Manti's expertise in abnormal pressure drilling and stimulation was a critical factor in developing this very









	challenging area at attractive investment levels. Sarita was one of the more challenging areas to drill and complete wells in South Texas. Although the temperatures are not extreme (1.6 /100' gradient) and the gas composition is fairly non-corrosive, the commingled nature of the various sand packages, combined with their original high pressure (17.8 PPG) and good porosity (25-28%), makes any drill well very challenging. Sarita was largely undeveloped due to extreme mechanical problems, which significantly reduced the number of available wellbores. The Baffin Bay structure located on the north flank of Sarita had very limited drilling and was essentially undeveloped.
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	Pursuing these untapped reserves economically presented Manti with four primary challenges: Depths and sequences of abnormal and drawn-down sands required carefully designed drilling programs to reach total depth with sufficiently large tubing to achieve target production rates as high as 30 MMCFD. The tight nature of the deep Frio required massive stimulation to achieve target rates. A massive frac-stimulation in excess of 1,000,000 pounds of high strength proppant was anticipated to maximize recovery from the deep abnormal pressure pays


	Manti worked towards a co-operative development of Sarita / Baffin Bay with Exxon who operates adjacent leases in both fields. Both companies had active drilling underway and Exxon is in the process of acquiring an extensive 3-D survey. Results of early drilling and 3D provided a basis for equity determination and Joint Ventures more conducive to efficient field development. Because the Frio pays occurred over a 3,500' interval, increased well density was necessary to reduce the field R/P from the 40 years. Manti applied to the Texas RRC to modify the field rules accordingly. Optimization of existing completions with recompletes and system debottlenecking tripled field rates to 15 M/D. In December 1996 Manti Operating completed drilling operations on the Mrs. Sarita Kenedy East #1, the well "they said couldn't be drilled." Located to the east of the town of Sarita, it was drilled to a total depth of 14600'. The casing program included setting strings with a combined string weight of over 2,000,000 lbs. and a mudweight that was as high 18.0 ppg during drilling operations. The final casing program included 24" at 1200', 16" at 6600', 11 3/4" at 11000, 9 5/8" liner at 12500, 7 5/8 " liner at 13500', 4 1/2" production liner at total depth, with a 7" by 4 1/2" production casing tie-back. This well took a total of 125 days to drill and produced at 15 M/D and 600 BCPD @ 5000 PSI. Total field rate was 30 M/D. The next phase of development at Sarita included a full rig year drilling wells targeted for the two main field O and M series field pays. These deep Frio age traps were set-up by the 1,000' South May and Sarita expansion faults. This expansion resulted in highly rotated fault blocks, which exhibited structural and stratigraphic complexity. From the onset of its discovery, efforts to map field pays using well control and seismic were challenging. A field study demonstrated that significant potential existed in Sarita. Since there had not been a well drilled in the field for over 10 years, the standard casing program used in the past was enhanced to give some additional flexibility to overcome potential problems. Fortunately, several of the drilling challenges that were present in the 1980's, were not present (i.e. charged sands) during the drilling of S.K East #1. As such, additional changes were planned on future wells that reduced the drilling costs and time. After drilling one well and performing three recompletes, increasing field production ten fold from time of purchase to 30 MMCFD at time of sale, Manti sold its interest to Headington Oil in May of 1997.