Study On The Exploitation Method Of Surfactant Injection In Shale Oil Reservoirs—

China's shale reservoirs have low porosity,high heterogeneity,and low formation pressure coefficients.They are exploited using conventional methods,which have problems such as low production,rapid decline in production,and low recovery factors.Aiming at these problems,this paper proposes an energized fracture method,that is integration of fracturing,closing and exploiting.This exploitation method can effectively supplement formation energy and increase economic benefits.In view of the fact that most of the shale reservoir rocks in China are weakly hydrophilic,this paper takes the Chang 7 reservoir in Ordos Basin as the target block,integrates reservoir engineering and numerical simulation methods to study the surfactant injection exploitation method,formulate a reasonable development plan,and realize the effective exploitationt of shale reservoirs.This paper comprehensively integrates reservoir engineering and numerical simulation methods to compare and analyze the five development methods of failure development,water energized fracture,surfactant displacement,surfactant huff-puff and surfactant energized fracture.The cumulative oil production surfactant energized fracture is the largest at 38479.39 m³.Compared with the failure development,water energized fracture,surfactant displacement,and surfactant huff-puff,the cumulative oil production of single well increased by 13817.48 m³,5648.20 m³,9956.95 m³and12279.92 m³.At the same time,through numerical simulation methods,the parameters of surfactant energized fracture are optimized.The optimization results are:the fracture half length is 110m,the fracture spacing is 60m,the fracture conductivity is 60×10^-3?m²·m,the liquid recovery rate is 25m³/d,the injection volume is 33000m³,the surfactant concentration is 0.1%and close time is 45d.The cumulative oil production of a single well is 42580.78m³.The results show that surfactant energized fracture can not only effectively supplement formation energy,improve shale oil production,but also overcome the disadvantages of strong adsorption of surfactants in shale reservoirs.It can effectively exploit shale reservoirs.This study provides important technical support for the exploitation of medium and high maturity shale reservoirs.