Production Performance Analysis of Hydraulically Fractured Horizontal Wells in Sulige Gas Field

Sulige gas field is the largest tight sand gas field in China. In order to boost gas production of individual wells and to maximize economic return, hydraulically fractured horizontal wells are widely applied in Sulige gas field in recent years. Influenced by special geologic condition and stimulation, the production performance of hydraulically-fractured horizontal wells in tight sand gas reservoir is obviously different from that of conventional gas wells, such as:①The dominant flow regime is linear flow rather than pseudo-radial flow and this flow regime may continue for several years;②The dynamic reserve, drainage area and productivity of producing wells vary with time quickly, especially in the early stage of production. By correctly identifying the percolation characteristics and production performance of hydraulically fractured horizontal wells in tight sand gas reservoir and combine with modern gas production analysis technology, 137 multi-stage fractured horizontal wells in Sulige gas field have been analyzed. Then a prediction chart of estimated reserves and new method of dynamic deliverability evaluation for Sulige multi-stage fractured horizontal wells are established. With these chart and methods, by using early stage production data, the dynamic reserve, drainage area and deliverability of multi-stage fractured horizontal wells can be predicted effectively with elapsed production time. In this paper, ultimate recoverable reserves, drainage sizes, drainage lengths and drainage widths of 57 multi-stage fractured horizontal wells in Sulige gas field are estimated. The results show that, in Sulige gas field, the average ultimately dynamic reserves and drainage sizes of multi-stage fractured horizontal wells are 2.8 to 3.4 times that of offset fractured vertical wells, and the average initial deliverability of multi-stage fractured horizontal wells is 4.0 to 5.0 times that of offset fractured vertical wells. Based on these data, the reasonable well spacing and gas flow rate of Sulige gas field are suggested.