扶余油田泉四段裂缝发育特征及其对开发的影响

Fracture Development Characteristics and Its Influence on Development in Q4 Member of Fuyu Oilfield

油田注水开发过程中,天然裂缝水窜具有强烈的普遍性和方向性。准确地认清天然裂缝产状,特剐是油层富集部位的裂缝分布特征,无疑是高含水裂缝性低渗透油田进行调整挖潜、提高注水采收率的基础和关键。充分利用现有的密闭取芯、开发动态等资料,对研究区天然裂缝的分布特性进行系统分析之后,深入剖析了裂缝对注水开发的影响机理。研究结果表明,扶余油田泉四段多发育规模小、延伸短的高角度裂缝,裂缝发育方向以东西方向为主;注水开发过程中,由于东西向裂缝发育,注入水迅速沿东西方向裂缝灌通而发生窜流,致使泉四段油层水淹,并在东西向油水井之间易形成剩余油;东西方向注入水体积波及系数小,水驱效果差。

In the process of water injection development, the water breakthrough of natural fracture has strong universalityand directivity. Accurate identification of the occurrence of natural fracture, especially the fracture distribution characteristicsof oil enrichment area, therefore, is the key to the improvement of water injection recovery for high water-content fracturedlow permeability oilfield. This paper makes full use of existing pressure coring and dynamic development data, systematicallyanalyzes the distribution characteristics of natural fractures in the studied area, and studies the influence mechanism of fractureon water flooding development. The study results show that small size, high angle fractures with short extension are highlydeveloped in Fuyu oilfield, with east-west fracture direction. Therefore the injected water will rapidly fill the east-west fractures,and water channeling will occur. This results in the water flooding and shut-in of oil wells in east-west direction, and theremaining oil is formed between east-west oil and water wells; the volume sweep efficiency of injected water in east-westdirection is small, and the water flooding effect is poor.