RIASSUNTO
This paper (SPE 50981) was revised for publication from paper SPE 37748, first presented at the 1997 SPE Middle East Oil Show held in Bahrain, 15-18 March. Original manuscript received for review 19 March 1997. Revised manuscript received 19 May 1998. Paper peer approved 26 May 1998.
Summary
The Athel silicilyte is a deep, tight formation containing light oil and dissolved sour gas. Because the potential volume is large, there is interest in early development. However, because individual wells are very expensive, every opportunity to gather information must be used. Well testing (production tests, pressure/volume/temperature (PVT) sampling, production logging runs, and pressure transient tests) has been used extensively to characterize the reservoir, to guide appraisal activities, and to shape the ultimate development. Key issues to be resolved before development are initial and sustained productivity and project costs.
Production tests have demonstrated both challenges and opportunities in producing from this unique formation. Pressure transient tests have indicated that effective reservoir permeability is one-tenth of cleaned core plug permeability. The difference is likely caused by some combination of sealed fractures and the plugging effects of bitumen in the reservoir. Production logging has been used to measure the fraction of pay contributing to production. Reservoir simulation models, based on well test results, have been used to predict initial rates and ultimate recoveries for various well types (vertical, multiple drainhole, and multiple hydraulic fractures). Project costs (number of wells required) are based on these reservoir simulation results.
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