Evaluation Of Favorable Areas Of Tangyuan Depression Natural Gas Reservoir

Tangyuan Fault depression is the northernmost sub-tectonic units of Yishu graben which is north-east spreading which has a considerable amount of oil and gas resources.In order to further meet the needs of oil and gas exploration,fully utilize seismic,logging,well logging,testing and analytical tests,and regional geological background data to carry out seismic geologic horizon calibration,fine stratigraphic division and comparison,and establish two-dimensional seismic isochronal frameworks.The seismic reflection characteristics of the major structural layers were determined,and it was determined that the target layer of this study was the Darienhe Formation.The study of sedimentary facies in the whole region was carried out to predict the formation of reservoirs,reservoirs,and caprocks,and the development zones of source rocks and favorable reservoir and cap combinations were identified.According to the results of tectonic,sedimentary research and reservoir prediction,combined with drilling conditions and hydrocarbon accumulation analysis,favorable exploration zones and targets are evaluated,favorable blocks are optimized,reservoir interpretation and sandstone prediction are performed,and geological reserves are estimated.Block dynamic characteristics and fluid characteristics and types of reservoirs provide drilling well locations.The lithology of the strata in the study area indicates land-derived clastic sedimentary rocks.Through observation of the core,a single-well core sedimentary facies model was established to identify three kinds of sedimentary facies,fan deltas,lakes and subaqueous fans,and further classified 9 sedimentary facies and 17 sedimentary facies types.The interpretation of the three-dimensional seismic area in the study area and the detailed interpretation of the key T3 trap indicate that the Tangyuan fault depression is a feature of the east-west zoning and the north-south block,and the central three-dimensional contiguous area is mainly in the II block range.The main gas-bearing horizon is the Darien River.The upper part of the group(top T3).The major fractures are F3,F4,f2,f3.The main positive structures are the Wangjiang structure of the I fault block and the Jixiangtun structure and the Huzhu Village structure of the II fault block.Based on a comprehensive analysis of the gas reservoir characteristics and fine structural interpretation of the Darienhe Formation,the favorable areas in the study area are forecasted into three categories: Type I forecasted favorable areas are considered development blocks and can directly provide basis for development and production..The Type II prediction favorable area is considered to be an evaluation block,which is to evaluate the exploitation value of gas reservoirs,and to explore and expand the scale of gas reservoirs and prepare them for production.The category III forecasting favorable area is considered as an exploration block,which is based on the evaluation of gas-bearing properties of different blocks and the discovery of new gas reservoirs,and can provide a basis for exploration and deployment.According to the above mentioned optimization and evaluation criteria,a total of three Class I profitable blocks and two Class II favorable blocks were selected for this study.