克拉玛依油田八区下乌尔禾组油藏小井距试验开发效果技术研究

RESEARCH ON DENSE WELL SPACING′S DEVELOPMENT EFFECT IN LOWER WUERHE RESERVOIR OF DISTRICT NO.8 IN KARAMAY OIL FIELD

克拉玛依油田八区下乌尔禾组油藏是特低渗透、微裂缝发育的巨厚层块状砾岩油藏。1979年采用反九点法面积井网试验开发,,井距从550m加密到275m,实现了全面注水开发。"九五"后仍存在采油速度低、见效程度低、压力保持程度低等问题,于2004年在油藏中部4+5两套加密井网的叠加区开展了小井距试验,由275m×388m反九点加密为138m×195m反九点,后期转为五点井网平行裂缝方向注水。同时,控制单井注水量,采用点弱面强的注采政策,试验五年以来通过井网加密调整改善水驱控制程度,缩小井距、提高压力梯度使低渗透率油层充分动用起来,小井距开发在油田生产中后期取得了较好的成效。

Lower Wuerhe reservoir of District No.8 in Karamay oil field is a thick massive ultra reservoir with low permeability and well developed microfracture conglomerate reservoir.And it was developed by water-flooding with inverted nine-spot pattern in 1979,the inter-well spacing diminished from 550m to 275m,flood development waw achieved thoroughly. After the ninth 5-year project,in the reservoir exists low oil production rate、low efficiency of response for the oil producers、low pressure maintenance degree,etc. In 2004 Close-Spacing Development of the two 4+5 well pattern in center district was conducted,the inter-well spacing diminished from 275m×388m to 138m×195m with nine-spot pattern,and then it transformed to five-spot water flooding pattern in the direction of parallel fractures. In the same time,the water injection of single well was diminished,and injection-production policy of 'weak at spots and intensive in the area' was adopted. We acquired preferable effect in the middle and late stage of field production through improving waterflooding control procedure with well pattern thickening,and employing less-permeable layer with dense well spacing、raised pressure maintenance degree.