摘要
简要介绍了断层封闭性研究现状和主要研究方法 ,阐述了油田现今地应力作用方向、大小对断层封闭性的影响 ,即在某一应力大小的条件下 ,现今水平主压应力方向与断层走向的交角越大 ,断层封堵油气的可能性越大 ,反之则越小 ;在某一断层产状条件下 ,作用于断层面的联合压应力大于或等于岩石抗压强度 ,有利于增强断层封闭作用 ,反之不利于断层封闭。以辽河坳陷西部凹陷笔架岭油田为例 ,选取该地区 4口井4 6个层段 ,计算了钻孔井壁崩落的优选方位及相应的现今最大水平主压应力作用方向 ,分析认为最大水平主压应力方向总体为北西向 ,与主干断层走向呈大角度相交或近于垂直 ,据此评价 4条主干断层总体上对油气的封闭性在沙河街组一段和东营组三段好 ,向浅部变差。采用声发射法测量了该区 10口井 4个层位现今最大水平主压应力数值和岩石抗压强度 ,据计算所得联合压应力评价了其中 3条主干断层的封闭性 ,总的变化趋势是深部好而浅部差。笔架岭油田的油气藏实际分布证实了评价结果是可靠的 ,这对于该区井位选择、区块评价。
This paper simply int roduces present situation and main methods of studying about fault sealing, and elaborates influence on the effect of fault sealing caused by the magnitude and direction of present maximum horizont al principal compressive stress, which indicates that, under stress condition gi ven, the bigger the angle between the direction of present maximum horizontal pr incipal compressive stress and fault trending, the bigger the possibility of fau lt sealing oil gas, otherwise, the smaller the possibility. When the united com pressive stress exerting on fault plane is bigger than or equal to compressive s trength of rock for a fault given, ability of fault sealing oil gas will be str engthened,on the contrary, it will be cut down. By taking Bijialing oil field in Liaohe basin as an example, author selects 4 wells involving 46 sections in order to determine the action direction of the present maximum principal compressive stress. Domina nt bearing of borehole break and corresponding direction of present maximum hori zontal principal compressive stress have been calculated by method of borehole b reak analysis. On the whole, direction of present maximum horizontal principal c ompressive stress is about NW, which is at an angle of about ninety degree to th e trend of the main fault. According to their relation between stress direction and fault trending at different parts, ability of 4 main faults' sealing oil ga s has been evaluated. The result shows that ability of fault sealing in Es 1 an d Ed 3 in depth is much higher than in upper place. The magnitude of present ma ximum horizontal principal compressive stress and compressive strength of rock h ave been measured by means of acoustic emission (AE method) technique for 10 wel ls involving 4 horizons of this region. By calculating the united compressive st rength of rock, author obtains an similar conclusion to former, from lower to up per part, ability of fault sealing changes into poorer. As a matter of fact, dis tribution of oil gas reservoir known has verified reliability of evaluation res ults. Therefore, the results are of geological and practical significance for ch oosing well position, for evaluating region of bearing oil gas, for calculatin g oil gas reserves and for formulating reasonable scheme of oil gas exploratio n and development.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2000年第5期127-131,共5页
Petroleum Exploration and Development
基金
辽河石油勘探局"笔架岭地区断层封闭性"科研成果的一部分
关键词
油田
地应力
断层封闭性
应力场
油气运移
Recent, Underground, S tress field, Fault, Closed reservoir, Effect, Quantitative analysis, Comprehensi ve evaluation, Liaohe depression
