The Studyonsedimentary Micro-facies Andpredictionoffavorable Exploration Area Inthe Shahejie Formation In The Northernpart Of Lixian Slope

The oil and gas resources in Lixian slope of Jizhong depression are very rich.The exploration potential in northern part of slope's remaining resources is great.So the systematic research of Shahejie formation's sedimentary micro-facies,the refined analysis of typical reservoir,the establishment of hydrocarbon accumulation model,the guidance of favorable exploration area and extending exploration direction are of significant theoretical and practical value for exploration and development of the region.The paper takes the northern area of Lixian slope's shahejie formation as the research object.Based on district geological data?3-D seismic data,drilling and logging data?core data and known reservoir data,with the theory instruction of Application of Sedimentology?Petroleum Geology?Reservoir Geology? Sequence Stratigraphy,to carry out the research of sequence stratigraphy,sedimentary facies and favorable exploration area,the following understandings have been achieved:(1)On the basis of well combined with seismic we have studied sequence stratigraphy,the upper Es3 to the lower Es1 are divided into two incomplete secondary cycle(SSQ1?SSQ2)and three third-order cycle(Es-SQ1?Es-SQ2?Es-SQ3).(2)Mainly combining with core observation and analysing of facies marks,the types of facies,single well facies and section facies,two types of facies in north area of Lixian slope of Paleogene are identified: Shahejie formation develops braided river delta at the bottom part and shore-shallow lake facies in the upper part from longitudinal direction.(3)Based on the research of sedimentary background analysis,in combination with ancient water system,the change of cuttings and detrital component content,it is concluded that shahejie formation's sedimentary source comes mainly from the northwest slope's Qingyuan-Gaoyang drainage system and Niutuo town bulge.(4)Combing with source analysis,using sand body's distribution and the study of seismic attributes,the plane distribution of sedimentary facies characteristics and regularities of vertical evolution at all levels of shahejie formation are analyzed.It's concluded that in the plane there is obvious evidence showing that the braided river delta plain regressing to north and shore-shallow lake bar sand body extending to north from the upper Es3 to the lower Es2.(5)After the refined analysis of typical reservoir,we think that reservoir is affected by the fault,more and more reservoirs have been found on structural high position,the reservoir type varies,including structural reservoir-faulted nose and faulted block reservoir,lithologic reservoir-sandstone up dip wedge-out reservoir and composite reservoir.(6)Combing north area of Lixian slope's tectonic development characteristics and hydrocarbon source rocks distribution and location,distribution pattern of sedimentary system and possible development of trap types,the transition zone between Yanling buried hill and Renxi subsag,Chu An nose-like structure belt are the favorable zones for the next rolling exploration.