中国克拉通盆地走滑断裂控储控藏作用OA

Successive breakthroughs have been achieved in the exploration of strike-slip fault-controlled oil and gas reservoirs within cratonic basins in China.However,the key issues concerning fault development mechanisms and large-scale reservoir formation and hydrocarbon accumulation mechanisms in this type of oil and gas reservoirs remain inadequately understood,which restricts their efficient exploration and development.Based on the research results of strike-slip fault-controlled oil and gas reservoirs in the Tarim,Sichuan and Ordos Basins,this paper investigates the formation mechanisms of widely developed strike-slip faults,elaborates on their controlling effects on reservoir formation and hydrocarbon accumulation,delineates their distribution patterns,and points out research directions.The following results are obtained.First,pre-Mesozoic"basin-wide strike-slip"fault patterns develop in Chinese cratonic basins,exhibiting weak strike-slip characteristics of stratified deformation and extensive distribution.In response to the oblique subduction of the Proto-Tethys Ocean,a widely distributed strike-slip fault system was formed based on the differential basement architecture of small craton.The segmented linkage and growth mechanism is the main factor controlling the large-scale development of long strike-slip fault zones with small displacements.Second,the outward propagation of minor en echelon/oblique strike-slip faults is conducive to the formation of extensive fracture networks.The fracturing,topographic difference and fluid-transport effects of the strike-slip faults facilitate the development of multi-stage and multi-type dissolution pores.The"microfacies+faulting+dissolution"differentiated composite effect controls the large-scale development of strike-slip fault-controlled reservoirs,which are distributed along strike-slip fault zones in the superimposed contiguous and band-like differentiated pattern.Third,under the four-element coupling of source,fault,reservoir and caprock,strike-slip fault-controlled complex petroleum systems are formed in the cratonic basins of China,exhibiting two hydrocarbon accumulation models,namely near-source and far-source strike-slip fault-controlled hydrocarbon accumulation.A series of small accumulations forming a large field are distributed diversely,and"sweet spots"are enriched and high-yielding along the strike-slip fault zones.In conclusion,pre-Mesozoic"basin-wide strike-slip"fault systems and their associated fault-controlled large-scale reservoirs and major oil&gas fields are well developed in the cratonic basins of China.The theoretical systems for the strike-slip fault formation and evolution,reservoir formation and hydrocarbon accumulation within cratonic basins are established,and the research directions of strike-slip fault-controlled oil and gas reservoirs are pointed out.The research findings provide a new pathway for the efficient exploration and development of deep and ultra-deep strike-slip fault-controlled oil and gas reservoirs.