The Study On Evaluation Of Fractured Effect Of Horizontal Well In Sulige Gas Field

Sugeli Gas Field is a kind of typical Tirple-Low gas ifeld, i.e., low-pressure,low-permeability and low-abundance, with its direct reflection as the poor physical propertyand the low permeability of the reservoir, as well as the low single-well output. More wellsand lower output, a development model for the regular wells, is difficult to achieve thetransformation of the tight gas resources into reserves and output, as well as the overalleffective development. Up to the end of2013，Changqing Oilifeld CoMPany has completeddirlling of more than450hoirzontal wells in Sugeli Gas Field.The drilling method of the hoirzontal wells in Sugeli Gas Field falls into open-holecompletion and non-cementing-liner, while the staged fractuirng process divides intoopen-hole packer utilization and hydraulic jetting. This thesis analyzes the calculation equationof the productivity of the homogeneous, stable and non-eccentric Boirsov hoirzontal wells.The measures and methods for improving the hoirzontal wells development, which isbeneifcial for the well selection pirnciples and the optimization of the fractuirng parameters,are obtained by analysis and evaluation of the eight factors which could have influence on thehoirzontal wells capacity, including the hoirzontal permeability of the reservoir, the effectivevertical thickness, the supply radius, the effective wellbore length, the heterogeneity of thereservoir, the rfacture conductivity, the length of the proper fracture and the method of stagedfractuirng. Based on the further analysis of the returning lfuid and its velocity atfer fractuirng,the important reasons for the low flowback velocity of the fractuirng fluid are concluded, inaddition to the scientific basis for improving the flowing eiffciency.Besides, suggestion are raised in this thesis for the well selection conditions, optimization ofthe rfactuirng lfuid system, and the promoted application of the high-strength nozzle alloynozzle, which would fiirther help increasing the production for the Sugeli Gas Field.