Development Characteristics and Influencing Factors of Upper Gas Reservoir in Jiaoshiba Anticline

In order to find out the reasons why there are obvious differences in the development effect of gas wells between upper gas reservoir (⑥-⑨ sublayers) and lower gas reservoirs (①-⑤ sublayers),in this paper it analyzes differences between upper and lower gas reservoirs in shale lithology,geochemical characteristics,pore type and reservoir physical properties based on fracturing data,field production performance,recoverable reserves prediction and geological analysis. Combined with the analysis of production characteristics of gas wells,it is believed that there may be a primary migration in the upper gas reservoir in the source rock,resulting in a high degree of natural gas enrichment in the upper part of the upper gas layer structure. This is the main reason for the difference of development effect between upper and lower gas reservoir gas wells. The high part of Jiaoshiba anticline is the favorable area for the development of upper gas reservoir,but its effective development scope needs to be delineated according to the recoverable reserves and economy of shale gas wells due to the limitations of technological level and gas price. Combining with the evaluation of stable production capacity and recoverable reserves of shale gas wells in upper gas reservoirs,it is considered that the development of upper gas reservoirs should start from the high part of the structure and gradually expand to the low part.