Depositional System And Distribution Of Hydrocarbon Traps In Wangguantun Area

Study area named Wangguantun is located in the territory of Wangguantun township of Cang county in the Hebei province.From the structural point of view ,it is located in the the region which is between Kongdian buried hill structural belt and Xuxi depression in the southern part of Huanghua depression, the total construction area of about 139km2. The region structure is complex, fault development, including Kongdong and Duanliuba-Xiaoji fracture system.Shahejie group and Kongdian group EK1 were transformed by Kongdong fault,Kongxi fault and Xuxi fault in Wangguantun area. Stratigraphic structure was very complex,that brings the work of petroleum exploration the great obstacle in this area. This paper aims at systematic studies on the sedimentary system under the constraints of isochronal framework. provide detailed, high-precision, and high-quality basic geological information for finding the lithologic reservoir. On this basis, by studying the factor that structure mode affect the pattern of basin development, explore the development mode and criterion of terrigenous sequence furtherly. And simulated deposition pattern,more intuitive analysis of depositional systems, At the same time,explore the sequence stratigraphy controlling factors in the end. By the division and correlation of the sequence and systems tract,analysis of the hydrocarbon accumulation mode furtherly, We have come to the regularity of hydrocarbon enrichment. We used sequence division trichotomy in my research process of my paper, take the unconformity and corresponded integration surface as the boundary of sequence demarcation, and employ High-resolution sequence stratigraphy method to divide the long-term and mid-term base-level cycle,take the lake spread surface as the boundary of the genetic sequence or base-level cycle sequence element. According the foundation of sequence stratigraphy, interpreting the earthquake well tie section, comparing the basal level cycle . EK1 and Shahejie group can be divided into five third-order sequences,fourth-order sequences,fifteen system sracts, fifteen half-cycles of mid-term datum plane and twenty-eight semi-cycle. And the Sequence One is Zao Five and Zao Four oil group, the Sequence Two is Zao Three ,Zao Two, Zao One and Zao Zero oil group,the Sequence Three is the Sha Three, the Sequence Four is the Sha Two ,the Sequence Five is the Sha One.Take the sequence as the analysis unit, analysis the deposition distribution of five sequences of Shahejie group and EK1. with analysising the lithofacies, lithofacies group type and electrofacies,we identified that Shahejie group and Ek1 developed four kinds of sedimentary facies which are alluvial fan facies,fan delta facies, delta, lake sediment facies and eleven sedimentary subphase.By comparison with connecting-well,the layer changing,the sandstone thickness changing ,the sediment charge changing and seismic facies, analysis flat feature of sedimentary facies in five sequences of Shahejie group and EK1.According to plane distribution characteristics and structure development of the sendimentary faces,we summarize five sequences of development mode ,filling style and the distribution regulation of the lithologic oil and gas reservior in each sequence mode.According to study above, the beneficial lithologic lithologic oil and gas exploration target area in each sequence is precdicted. The early stage development of Sequenceâ… forms delta sedimentary body. Sequenceâ…¡develops channel sand bodyalong the long axis of the fault which distributes at the westhern and the easthenpart of the hole; Sequenceâ…¢develops fan delta sedimentary body; sequenceâ…¤at the low location develops biological limestone and sandstone body.