铲式断层空间特征研究进展综述

A REVIEW ON THE RESEARCH PROGRESS OF SPATIAL CHARACTERISTICS OF LISTRIC FAULT

受地震资料解释多解性和局限性的影响,沉积盆地中深部地震资料解释品质差,靠地震解释来反映地下断层信息并不能揭露断层空间本质发育特征。鉴于此问题,笔者以脆塑性断裂发育特征、断层折射机理为基础,从断层空间位移量关系、倾斜角剪切法模型、断层面空间联合应力分布等方面对铲式断层空间特征进行研究。综合研究表明:铲式断层面上盘和下盘构成的空间并非楔形模式,而是局部构造紧闭区和局部伸展剥离区交替形态;由断层空间各位移量关系图解可知,铲式断层走向位移量和倾伏向位移量之间的夹角θ越小,走向应力作用越大,引起地层牵引程度就越高,形成的有利储油构造储集厚度就越大;利用倾斜剪切法模型可预测铲式断层实际滑脱深度,加强对中深层构造特征的认识;当铲式断层面折射裂缝被矿脉等充填时具有封堵性,当铲式断层面空间联合应力大于或等于其作用处岩石的抗压强度时,造成断层面处裂隙闭合或断面物质压紧,有利于封堵油气。

Affected by the multiple solutions and limitations of the seismic data interpretation, seismic data interpretation in sedimentary basin is of poor quality and the fault information from seismic data interpretation can 5 t expose the characteristics of the fault space development. With that in mind, based on the brittle plasticity fault development characteristics and fault refraction mechanism, the listric fault spatial characteristics were studied from the aspects of fault spatial displacement relation, inclination angle shearing method model and fault plane spatial combined stress distribution. The comprehensive study results show that the space formed by the hanging wall and footwall of listric fault isn 5 t in a wedge mode but an alternative mode between local compact structure zone and local extension peeling zone. According to the diagram of the displacement relation of the fault space, the smaller the included angle 0 between listric fault strike displacement and dip displacement, the greater the stress along trend, the higher of the traction degree towards the stratum, and the thicker the oil-bearing structure favorable to accumulate oil. Inclined shearing method model can predict the actual slip depth of listric faults, strengthening the consciousness of the structure characteristics of middle and deep structures. Listric fault is closed while it’s faultplane refraction crack filled by mineral vein, and when combined stress of listric fault plane space is greater than or equal to its compressive strength affecting on rocks, it will cause the closure of the crack or the material compaction, which is favorable for the seal of oil and gas.