松辽盆地北部深层断陷类型及风险勘探领域优选

Fault depression type and optimal selection of risk-taking exploration field in deep layer of northern Songliao Basin

孙立东

Sun Lidong

中国石油大庆油田有限责任公司勘探开发研究院，黑龙江 大庆 163712

Research Institute of Exploration and Development, Daqing Oilfield Co. Ltd., PetroChina, Daqing 163712, China

松辽盆地北部深层断陷构造复杂，制约了断陷优选评价工作。依据沙河子组残留特征与演化规律，将深层断陷划分为“持续沉降型、改造叠合型、继承反转型、改造叠合反转型”4种类型。研究表明：复杂改造叠合型盆地经早期改造并残留下来，往往成为断陷主体或沉积中心，其烃源岩条件较好，同时早期构造活动产生了大量气源断裂，并使地层上倾或者削截方向直接与储集体接触，有利于天然气聚集；持续沉降型断陷盆地沉积环境稳定，有利于暗色泥岩发育，具有较好的源岩条件，后期改造作用弱，有利于天然气保存；将深层断陷划分为Ⅰ，Ⅱ，Ⅲ类勘探区，明确了近期风险勘探的有利区带。

The structural complexity of fault depression constraints its optimal selection and evaluation in deep layer of northern Songliao Basin. According to the residual characteristics and evolution rule of Shahezi Formation, the deep fault depression can be divided into four types: continuous subsidence type, reformation superimposing type, succession reversion type and reformation superimposing reversion type. The studies show that the main body of fault depression or depocenter is usually left in complex reformation superimposing basin, which has good source rock after early reformation. Meanwhile, many gas source faults and good contact directly between updip or truncated direction and reservoir formed by the early structural activities are beneficial to natural gas accumulation. Stable deposition environments in continuous subsidence fault depression are beneficial to dark mudstone development. Good source rock and weak reformation in late period are beneficial to natural gas preservation. Through analyzing comprehensively, the fault depression is divided into three types of exploration regions and the recent favorable zone of risk-taking exploration is defined.

10.6056/dkyqt201206001