Study On Rules Of Chang9Reservoir Accumulaiton And Distribution In Dingbian Area Of Ordos Basin

Based on the information of drilling, core and well logging and analytical data inDingbian area which is in the northwestern of Ordos Basin, reservoir enrichment regularity ofChang9oil reservoir of the study area is discussed in this paper, including the condition ofreservoir, the power of reservoir, the peirods of reservoir, translocation system, the types ofreservoir and the controlling factors of reservoir. The analysis technique of hydrocarbongeochemical, the analysis technique of reservoir’s peirods, the analysis technique ofhydrocarbon migration pathways, and the comprehensive analysis technique of accumulationmode are used in this paper.Chang9reservoir of the study area is mainly developed in the Rejoinder River delta plainand delta rfont; reservoirs are mainly developed in the sand body rfom microfacies ofdistirbutary channel and interdistirbutary bay. Reservoir rock types are mainly arkose andlithic arkose. Cements are mainly siliceous cement, laumontite and chlorite iflm，less ironcalcite. The pore types include intergranular dissolved pore, feldspathic dissolved pore androck fragment dissolved pore. Diagenesis is mainly compaction, chlorite cementation,laumontite cementation, siliceous cementation, ferriferous calcite cementation and dissolution.The main oil source of the reservoir is from Chang7hydrocarbon source rocks, whosepattern is oil and gas migration accumulation.The reservoir type of Chang9Reservoir is mainly structural-lithologic reservoir andlithological reservoir, which was formed in Early stage of Early Cretaceous (140~150Ma).The northwestern patr of Chang9Reservoir has good petrophysical property and cleardifferential phenomenon of oil and gas, which mainly developed structural-lithologic reservoir.The central and eastern part of Chang9reservoir has poor petrophysical property and itsdifferential phenomenon of oil and gas is not obvious, which mainly developedlithological reservoir. The reservoir-forming power of Chang9reservoir is mainly theresidual pressure of Chang7hydrocarbon source rocks. For Chang9reservoir,fractures are mainly vertical pathways for migration of oil and gas and vertical overlappedsand body also supplies effective migration passage. The oil-water relation of Chang9reservoir is complex, the oil-water distirbution of single well includes types of pure oil,pure by hydrocarbon-generating intensity,the distribution of reservoir is controlled by the condition of oil source，the development of cover，the properties of reservoir，the cracks, etc.