Application of Horizontal Waterflooding To Improve Oil Recovery From Old Oil Fields

摘要

This paper discusses the results of the application of horizontalwaterflooding technology to improve the recovery of oil fromolder fields. A multi-disciplinary approach combininggeological interpretations, rock mechanics evaluations,reservoir simulation studies, and drilling technologies wasemployed. A range of reservoir conditions in which thetechnology is viable is discussed and the results of the fieldtests are presented.The major focus has been on the shallow sandstonereservoirs in northeast Oklahoma and southeast Kansas. It hasbeen demonstrated that additional oil can be recovered inseveral different reservoir environments in these older fields,by utilizing a combination of horizontal and vertical wells.Two previous SPE papers described the results of aDepartment of Energy (DOE) supported horizontalwaterflooding pilot located in the Wolco Field, Osage County,Oklahoma.The technology has continued to evolve over time. Thekey to assessing the potential for a horizontal well applicationis a thorough understanding of the reservoir description,including the oil saturation, depositional environment,reservoir pressure, permeability, and an evaluation of anyprior production and/or injection. Other parameters include thelength, spacing, positioning and orientation of the injectorsand horizontal producers in the target zone. Use of rotarysteerabledrilling equipment has made it possible to drillunderbalanced, short-radius horizontal laterals at a low cost.Special procedures have been adopted to permit the transportof openhole logging equipment through the short-radius curveto the end of the lateral, providing a good description of reservoir properties and detecting the presence and orientationof natural fractures.Results from several successful horizontal well projects arediscussed. These include (1) two horizontal waterfloods inshallow Bartlesville sandstone reservoirs, (2) recovery from arim of moderately heavy oil underlain by water, and (3) anapplication of horizontal waterflooding in a moderately heavyoil reservoir.