Abstract:
This paper presents the mechanism of cased hole formation resistivity (CHFR) measurements and its various applications on three aging wells in OGDCL fields, named X, Y and Z field in the paper. Two of the three are oil wells and another one was producing gas condensate. All reservoirs under investigation have relatively low porosity. After reviewing the well history and the reservoir properties, and also the challenges on reservoir monitoring and residual hydrocarbon identification, detailed planning on cased hole resistivity survey, field execution, integrated interpretation and workover were carried out. After-workover production is also discussed. For the first oil well, after cased hole resisitivity logging and workover, 810 B/D of oil with 15% water cut produced from two sands in between highly depleted permeable sandstone, all those sands have been producing for very long period and were squeezed off due to nearly 100% water production. Until now, two perforations have been made on the second oil well, the first perforation opened five zones below old completions, the well produced 430 BOPD with 50% water cut initially; after the second perforation over the zone with less depletion identified by the cased hole resistivity, the well delivered 1225 BOPD with 28% water cut. For the gas condensate well, by comparing to the open hole deep resistivity shows different degree of depletion on a massive sandstone reservoir which was tested with good gas/condensate rate immediately after the time the well was drilled but never completed for production. Results of the re-perforation support the conclusions derived from CHFR measurements. The impact of pressure-drop on the gas condensate reservoir production is discussed for this well. Based on results from three OGDCL fields obtained so far, the reservoir monitoring with cased hole formation resistivity has re-defined the reservoir characteristics and opened new avenues and horizons for enhancing oil recovery.
Page(s):
295-310
DOI:
DOI not available
Published:
Journal: Proceedings SPE-PAPG Annual Technical Conference, Volume: 0, Issue: 0, Year: 2007