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.
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