A Study On Injection Pressure Drop Analysis For TaHe Reservoir

Owing to the particularity of reservoir pore space of fracture-cavern carbonate rock in Tahe, it generally has the features of fracture and cave, which seeping law is complicated and its dynamic analysis cannot be analyzed by conventional analysis. Aiming at fracture-cavern carbonate rock reservoir characters in Tahe oilfield, the paper studies on geology at first and develops a new physical model which can describe the features of fracture and hole in Tahe reservoir. On the base of the method, the paper simplified the fracture-carven system to a non-continuous medium, and a new mathematical model has been established. Then the solution method of the new mathematical model has been researched and the paper analyzed the factors which influence injection pressure drop curve. At last, a new method for pressure drop testing curve analysis of fracture-carven reservoir has been deduced and it compiled the program on the basis of the new method. By using the research method, it analyzed pressure drop data of Tahe reservoir, calculated the controlled reserve as well as the volume of fracture and cave and provided theory for scientific development of single well.The main achievements acquired in this paper lie in the following:(1) According to the fracture-cavern's feature of Tahe reservoir, carbonate formation can be composed by triple porosity media of large fracture, big hole and macro-fracture-carven, which is non-continuous;(2) The conclusion that Tahe exists large fracture and cave was draw by the injection drop data of two injection wells;(3) It is hard to simulate the injection pressure drop curve by general numerical simulation. To describe fracture-carven needs new mathematical model;(4) New model of injection pressure drop testing data analysis was established in the condition of continuous media which exists fracture, cave, macro-fracture and macro-carven. What is more, new method of injection pressure drop testing analysis was established. At last, the factor influence pressure drop curve was calculated;(5) Real injection pressure drop testing data of Tahe reservoir was analyzed. Fracture and cave's feature was evaluated. Control reserves of single well was calculated through well testing interpretation.