不同序级走滑断裂对碳酸盐岩储集层发育的控制差异

Differential Controls of Strike-Slip Faults of Different Orders on Carbonate Reservoirs

断控岩溶体系储集空间结构差异制约该类油藏高效开发。目前,对高序级走滑断裂储集层储集空间结构研究较深入,但对低序级走滑断裂储集层储集空间结构研究较少。以塔里木盆地北部坳陷富满油田为例,从断裂活动强度、沉积环境、岩性等方面展开分析,对比不同序级走滑断裂储集层储集空间结构成因及差异,并分析了低序级走滑断裂的成因及勘探潜力。高序级走滑断裂活动强烈,储集层在剖面上呈倒三角式破碎,储集层规模由上至下逐渐减小;低序级走滑断裂活动强度相对较弱,储集层在剖面上呈正三角式破碎,储集层规模由上至下逐渐增大。低序级走滑断裂对地层的破碎规模影响有限,密集发育的裂缝网络可以导致储集层大规模破碎,影响储集层发育的主要因素是沉积环境和岩性。富满油田深层低序级走滑断裂由西向东可分为3个区域,勘探潜力大。

Differential spatial structures of the fault-controlled karst reservoirs constrain the efficient development of these reservoirs.The pore structure has been substantially studied for high-order strike-slip fault-controlled reservoirs,but rarely for low-order strike-slip faultcontrolled reservoirs.Taking the Fuman oilfield in the northern depression of the Tarim basin as an example,different orders of strike-slip fault-controlled reservoirs were analyzed from the aspects of stress,depositional environment,and lithology,to compare their genesis and differences of pore structure,and the origins and exploration potentials of low-order strike-slip faults were examined.It is found that high-order strike-slip faults underwest strong faulting,resulting in an inverted triangular fracture pattern in the reservoir,with a decreasing scale from top to bottom.In contrast,low-order strike-slip faults experienced relatively weaker tectonic stress,leading to a normal triangular fracture pattern in the reservoir,with an increasing scale from top to bottom.The fracturing scale induced by low-order strike-slip faults is limited;however,a densely developed fracture network can lead to extensive reservoir fracturing.The primary factors influencing reservoir development are the depositional environment and lithology.The deep-seated low-order strike-slip faults in the Fuman oilfield can be divided into three zones from west to east,showing significant exploration potential.