Production Prediction of Fractured Horizontal Well in Shale Gas Reservoirs Considering Long-Term Flow Conductivity

Production of a horizontal well in shale gas reservoir is high initially after fracturing,but declines rapidly later.There is no practical decline profile that can be considered to predict such production in China now.In this background,experiments of long-term flow conductivity were conducted with sanding concentration of 2.5 kg/m2 and 1.0 kg/m2 respectively.Results showed that the conductivity declined approximately 43% in the first 2 days due to proppant embedding and crushing,and at lower rate 4 days after.The experiment results were used in the numerical simulation of a well located in southeast of Sichuan;the production in the fixed-conductivity case was considered 2 or 3 times of that in the long-term flow conductivity case.Ten-year performance prediction demonstrated that the production cycle of sample well could be divided into 3 stages:year 1-2,when the decline rate could be 42%-46%,year 3-4,when the decline rate was stabilized within 27%-37%,and year 5-10,when the decline rate was lowered to 4% or less.It was therefore concluded that proppant for fractures in shale reservoirs should be evaluated and selected using the results of long-term flow conductivity experiments,and the production decline profile can be considered to determine the re-fracturing time for fractured horizontal wells in shale gas reservoirs.