| Bei X62 block is located in the southwestern part of the Beidong sub-concave of the Bell Depression and has good prospects for exploration and development.Research shows that the discovered oil and gas in the main target layer,the Nantun Formation,is closely related to the faults developed within it,and the oil and gas is mainly distributed in the area interposed by the main faults.However,the current research on faults in the Bei X62 block mainly focuses on the analysis of their development and distribution characteristics,the determination of activity periods and system delineation,and lacks the determination of oil source faults and quantitative evaluation of the lateral closure of faults,and lacks the discussion of the control role of faults on oil and gas formation,which seriously restricts the depth of oil and gas exploration.Therefore,based on the summary of previous work,the thesis uses various existing oil and gas exploration data to delineate the fault system of the Nantun Formation in the Bei X62 block by analyzing the characteristics of fault development and determining the period of fault activity.Accordingly,the oil source faults of the Nantun Formation in the Bei X62 block are determined by analyzing the distribution characteristics of source rocks and determining the hydrocarbon formation period;the lateral closure of the faults in the Nantun Formation in the Bei X62 block is quantitatively evaluated by comparing the relative magnitude of the actual SGR value of fault rocks and the lower limit of the lateral closure SGR value of the faults,and the two are combined with the type of hydrocarbon reservoir and the law of hydrocarbon distribution to investigate the role of faults in the Bei X62 block in controlling hydrocarbon formation in the Nantun Formation.The faults in the Bei X62 block are combined with the reservoir type and hydrocarbon distribution rules to study the role of faults in controlling the formation of oil and gas in the Nantun Formation.The results and understanding obtained in this study are mainly in the following five aspects:（1）The faults within the Nantun Formation of the Bei X62 block belong to the early fault system,including early extensional faults,early extensional-mid-term tensional-torsional faults and early extensional-mid-term tensional-torsional-late reversal faults,of which the former are mainly distributed in the southwest;the latter two are mainly distributed in the southeast.（2）There are 5 oil source faults in N1Ⅰ sand group,N2Ⅲ sand group and N2Ⅳ sand group in Bei X62 block,which are mainly distributed in the north;11 transmission faults are developed in Bei X62 block,which are mainly distributed in the southeast;the rest are blocking faults,which are mainly distributed in the southwest.（3）The lateral closure characteristics of the faults in the N1Ⅰ sand group,N2Ⅲ sand group and N2Ⅳ sand group are basically the same,most of the faults are closed laterally,and only a very few faults are open laterally at the end.（4）The oil and gas reservoir types in the Nantun Formation of Bei X62block are mainly broken block and broken nose reservoirs;the oil and gas in Bei X62 block is mainly distributed in the second member of Nantun Formation longitudinally,and its Nantun Formation oil and gas is mainly distributed in the parts sandwiched by F1 fault and F2 fault and F1 fault and F7 fault.（5）The role of faults in the Bei X62 block on the formation of oil and gas in the Nantun Formation is mainly manifested as follows:the oil source fault provides a transport channel for the vertical transport of oil and gas;the F1 fault provides a transport channel for the lateral transport of oil and gas to the Bei X62 block;the sealing fault provides a shielding condition for the formation of oil and gas.The above research results can provide a theoretical basis for oil and gas exploration in the Nantun Formation of the Bei X62 block. |
