This paper (SPE 52993) was revised for publication from paper SPE 36536, first presented at the 1996 SPE Annual Technical Conference and Exhibition, Denver, 6-9 October. Original manuscript received for review 11 October 1996. Revised manuscript received 22 September 1998. Paper peer approved 23 September 1998.
Summary
A Wireline retrievable coring system for use with conventional drilling equipment is described. The coring system was developed and tested for application in evaluating coalbed methane prospects where a large quantity of core is required, and it is essential that the core is processed soon after it is cut. A drill plug allows for alternation between coring and drilling without tripping the drillstring. The system is particularly advantageous for coring long intervals, multiple zones relatively close together, or when the exact target depth is unknown. The system has been used to core more than 4940 m (15,057 ft) in Poland, Germany, and France, with a combined core recovery of 94%. In addition, the impact of varying rig costs on total savings is factored into the overall economic evaluation of the system.
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The 36th International Technical Conference on Circuits/Systems, Computers and Communications
