Development Adjustment of Heterogeneous Sandstone Reservoir at Late Period of High Water Cut Stage

Abstract

Abstract Severe heterogeneity of continental sandstone reservoir has set great difficulty for understanding and smoothly developing oil field. But can we make effective adjustment at late period of high water cut stage making use of this characteristics? Daqing oil field has made useful attempt, including developing new technologies to deepenly tap the two sides potential of thin, poor and thick reservoirs through fine reservoir description; conducting development adjustment in old area by taking advantage of various differences in oil field development caused by heterogeneity to realize oil production replacement and maintain oil production stabilization at the level of relatively high annual oil production; fluid production and water cut increase rate are also effectively controlled, opening up a new way of maintaining oil production at late period of high water cut stage, and obtaining considerable economic benefits. Practice proves that this set of methods are novel in thought and feasible economically, and can promote the development of reservoir description and developing technology. So systematic introduction is presented here just for reference for the same type of oil fields. Introduction By the end of 1990, Daqing oil field has been developed for 30 years, recovering more than 60% of the recoverable reserves, the comprehensive water cut of La, Sa, Xing oil reservoirs as the mainbody of Daqing oil field has been to 80.23%, entering late period of high water cut stage. At this time, according to experience of the test of small space injection development conducted in 60'S in Daqing oil field, the increase of fluid production index and fluid oil ratio of oil wells will dramatically accelerate, and oil production will decrease rapidly (Fig 1.2), producing degree of reserves deepens, primary adjustment of strata of series whose main target is low permeable reservoir has basically been completed. Targets of the ongoing secondary infill drilling would be the low permeable thin reservoirs in which residual oil scatter in a high degree and the ultra-low permeable reservoirs in which oil immersion and oil patch are main occurrences and whose geologic reserves are not calculated (we call it "untabulated reservoir"), single infilling well production and controlled recoverable reserve will also decrease dramatically(Fig 3); as the increase of water cut of old wells, the oil stimulation result of each measure also decrease annually. Facing this difficulty, can we continuously realize high and stable oil production through effective adjustment in old area to meet the needs of national economy to oil production? P. 615