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松辽盆地北部T2反射层断裂与中浅层油气的运聚成藏关系紧密,揭示T2反射层断裂密集带的成因机制对指导油气勘探至关重要.基于松辽盆地北部区域地震解释,从分析断裂发育特征着手,以断裂形成演化过程为主线,系统剖析了盆地演化不同阶段断裂的变形机制,揭示了T2反射层断裂密集带的形成机制及其对油气运聚成藏的指示作用.研究表明,T2反射层断裂密集带是在断陷演化基础上,在断陷期断裂先存构造、泉一二段塑性泥岩盖层水平拆离作用和近EW向拉张应力场的控制下形成的,全区以近SN向拉张机制伸展型密集带为主,NE向、NW向和近EW向斜拉机制调节型密集带和走滑调节型密集带零星分布.盆地反转期受断陷半地堑、基底深大断裂和左旋压扭变形场控制形成反转构造带的同时,反转构造带内的断裂密集带被逆时针旋转改造而定型,呈NW-NNW向展布为主.反转构造带内T2反射层NW-NNW向断裂密集带边部断裂和未反转区带内T2反射层近SN向断裂密集带边部断裂长期活动,与油气大量生排烃时期匹配,是中浅层油气运聚成藏的油源断层.
The T2 reflection layer in northern Songliao Basin is closely related to the migration and accumulation of middle-shallow oil and gas reservoirs. It is very important to reveal the genesis mechanism of the T2 reflection layer fault-intensive zone to guide oil and gas exploration.Based on the seismic interpretation in the northern Songliao Basin, The main fault mechanism is fracture development and evolution. The deformation mechanism of faults in different stages of basin evolution is systematically analyzed, and the formation mechanism of fault-intensive zone in T2 reflection layer and its indication to hydrocarbon migration and accumulation are revealed. On the basis of faulted evolution, the intensive belt of fault T2 reflection layer is formed under the pre-fault faulting structure in the fault depression, horizontal detachment of the plastic mudstone cap rocks in the first and second segments of the spring and the tensile stress field near the EW direction, The whole area is dominated by the stretching-type intensive belt near the SN stretching mechanism, and the sparsely-distributed belt of the regulation intensive belt and the strike-slip regulation intensive belt in the NE, NW and near EW strike-pull mechanisms. At the same time, the fault-intensive belts in the inverted structural belt were revolved counterclockwise to remodel and shape, showing mainly NW-NNW-direction distribution. Structure belt The NW-NNW fracture of the T2 reflection layer and the T2 reflection layer in the non-inverted region near the fault zone are characterized by the long-term activity at the edge of the intensive fault zone, which is consistent with the period of hydrocarbon generation and expulsion. Polygene reservoir source fault.