低渗薄层油藏多垂直裂缝水平井产量计算公式

随着越来越多的水平井压裂技术应用于低渗透薄互层油藏,准确地确定多垂直裂缝水平井的产量意义重大.在假设各薄互油层物性各异、各裂缝流量不相等的条件下,分析研究了各裂缝周围的渗流场分布特征.采用渗流面积等值法,把多垂直裂缝系统水平井等效为水平井与垂直井的组合.应用镜像反映及势的叠加原理,对裂缝系统的产量公式进行了详细推导,并结合Renard-Dupuy公式,得到了多垂直裂缝水平井产量公式.实例的计算结果表明,水平井经压裂后产量明显增加,各垂直裂缝的产量不相等,中间裂缝较边部裂缝产量小.由此说明在压裂缝数量确定的情况下,应尽量增加裂缝间的距离,以增加各裂缝的泄油半径,以此来提高单井产量.

Production formula for the horizontal well in thin low-permeability reservoir with multiple vertical fracturing fractures

The yield of low-permeability thin interbed reservoir can be increased by drilling a horizontal well and producing vertical fractures by hydraulic fracturing for connecting the thin layers.The features of the seepage field around the fractures are analyzed under the hypotheses of all the thin layers having different property and all the fractures having different flow rates.The horizontal well system with multiple vertical fracturing fractures can be regarded to be the combination of one horizontal well with several vertical wells according to the principle of equivalent seepage area,and based on this,the production formula of this horizontal well system is obtained according to the principles of mirror reflection and potential superposition and based on Renard-Dupuy formula.The calculation result for a case shows that the yield of the fractured horizontal well obviously increases,and that the yields of the vertical fractures are not equal to each other,the yield of the middle fracture is smaller than the that of the fractures in two sides.It is shown that the distance between two fractures should be increased as much as possible under the condition of determined fracture number to increase the yield of each fracture and furthermore increase the yield of the horizontal well system.