塔里木盆地北部地区主要断裂带构造应力场与油气运移

TECTONIC STRESS DRIVING AND MIGRATION OF GAS AND OIL IN NORTHERN TARIM BASIN

塔里木盆地北部地区的断裂构造对油气的形成、运移、储集和保存具有极为重要的控制作用。大型多期活动断裂控制了大型隆起和拗陷的形成、发展和演化，是各时期油源纵向运移的良好通道；小型或次级断裂以及由断裂产生的节理、裂隙等，可改善储层的性能，是该区各种储油构造形成的主要构造条件。笔者认为，油气的运移和聚集最主要的条件是构造应力驱动。为了将断裂构造活动的构造应力场与油气运移的物质场结合起来，建立了构造应力驱动与岩内流体运动的理论方程，这个方程反映了构造应力、流体内压和运移势之间的微分关系。笔者对该区已知油田不同类型断裂机制的储油构造型式、油气富集条件及部位进行了理论分析和模拟计算，进而对主要构造区块选择典型剖面模拟计算运移势状态，并与已知油田进行类比，找出油气运移和储集的有利地区，为塔北地区油田勘探提出了预测意见。

The fault structures play an important role in controlling the formation,migration,accumulation and preservation of gas and oil in the northern Tarim Basin.The large repeatly active faults not only controlled the formation,development and evolution of large uplifts and depressions,but also acted as channel ways for vertical migration of oil and gas in different epochs.Small or second-order faults,and joints and cracks caused by faulting may improve the reservoir property,and are the major tectonic features that lead to the various structural trap of oil and gas in the region.The authors think that the action of tectonic stress may create the most important conditions to drive the migration and accumulation of oil and gas.For the purpose to integrate the tectonic stress field responsible for the faulting with the material field in which migration of oil and gas takes place,a theoretical equation is established for the correlation of tectonic stress driving and fluid movement in the rocks.It represents the differential relation between tectonic stress, internal flow pressure and migrating potential.Theoretical analysis and model calculation have been done for different oil-bearing structural types,their concentration conditions and locations in the known oil-fields in the northern Tarim Basin.The states of migration potentials have been simulated and calculated for a few typical sections in some major tectonic domains.The results obtained are compared with that of the known oil fields to find out the most likely areas for oil and gas exploration.