文东油田沙河街组三段中亚段油藏裂缝发育规律及其对注水开发的影响

对文东油田古近系沙河街组三段中亚段油藏利用岩心、薄片观察、压力恢复试井研究了天然裂缝的存在。通过凯塞效应、波速各向异性、古地磁、井孔崩落掉块等方法研究了地应力特征。最大水平主应力方向与大断层、天然裂缝走向垂直或近于垂直,人工裂缝方向基本平行于最大水平主应力方向。运用主曲率法定量预测天然裂缝走向,长度和强弱。天然裂缝以构造成因为主,主要形成于古近纪东营组沉积时期。在不同的开发阶段,人工裂缝和天然裂缝对注水开发影响程度不同。针对目前天然裂缝已经基本闭合的事实,在进行注采井网部署时重点考虑人工裂缝对开发的影响。

Pattern of fracture occurrence and its influence on waterflooding in the Es3 reservoirs of Wendong oilfield

By analyzing cores,thin section and pressure build-up tests,this paper discusses the occurrence of natural fractures in the reservoirs.The earth stress characteristics are identified through research on Kayser effect,seismic anisotropy,paleomagnetic and borehole cave-in.The direction of maximum horizontal major stress is perpendicular or near perpendicular to the direction of the major faults and natural fractures,while is in parallel with the direction of artificial fractures.The direction,length and strength of natural fractures are quantitatively predicted through the methodology of main curvature.The natural fractures are predominantly of tectonic origin and were mainly formed during the deposition of the Tertiary Dongying Formation.During different stages of development,natural and artificial fractures have different degrees of influences on waterflooding.Given the natural fractures being basically closed,attentions should be focused on the artificial fractures when designing injection-production pattern.