Investigation On The Optimization Of The Horizental Development Well Pattern In South Su 53 Block

The structure of southern Su 53 block locates in the mid-belt of north Yishan slope in Erdos Basin.Its primary structure is a uniclinal structure which is tilting northwest.The depositional faces of targeting layers He 8 and Shan 1 are braided river and meandering river respectively.The reservoir body belongs to channel bar,point bar and channel sand,which are the primary favorable microfaces of the south Su 53 block.Aerially,the sand bodies are distributed as northwest-southeast strip with local continuity.Vertically,the effective sand bodies are distributed as being imbricated with poor lateral continuity,which causes the complexity and severe heteogeneity of the gas reservoir.We forecasted the effective sand bodies distribution through analyzing geological models,in-situ stress and natural fractures.Based on that,we predicted the favorable gas zones by suing seismic attributes.In the area of investigation,the sand bodies appear distributed continuously.Among that,sand bodies in the mid and west part(Su 53-3,Su 53-4)have larger thickness,with a maximal value of 30 m.The sand body in the east part(Su 53-8)has a thickness less than 3 m.The gas zone and sand thickness distribution have good agreements.We calculated the average production capacity of the 38 horizental wells as 44×104m3/d by using the “one point” empirical equation in Sulige area.Also,by using 9 different methods such as material balance method,production dynamics analysis method,log-log regression method,we forecasted the average controlled reserve of each single well as 7039×104m3.Furthermore,by setting up the well-controlled dynamic reserve forecasting graph of each well,we concluded that the ultimate well-controlled dynamic reserve is 12391×104m3.Through numerical simulation for south Su 53 area,we conclude that the optimal horizental lateral length should be between 800-1000 m.The lateral direction needs to be perpendicular to the in-situ stress,which is around 350°.The optimal well spacing is 600 – 800 m through a comprehensive analysis,including analyzing well test after fracturing,well pattern density at ecnomical limit,optimal gas production rate,reserve abundence,equivalent percolation and numerical simulation results.Based on the sand bodies distribution,the diamond-shaped non-regular well pattern is utilized.The well locations are cross-overd between rows.By comprehensively analyzing well pattern,the relationship between well pattern and in-situ stress,well spacing,horizontal well parameters,production capacity and well-controlled reserve,we find that the current horizonal well pattern has good adaptibility with the gas reservoir geology.The technically economical requirements of horizental well development are achieved.