含多条垂直裂缝的水平压裂气井产能研究

STUDY ON PRODUCTION PERFORMANCE OF FRACTURED HORIZONTAL GAS WELLS WITH SEVERAL VERTICAL FRACTURES

文章对水平压裂气井的渗流过程进行了分析,将气体从地层流入水平井底的压降分为三部分一是气体从地层基质流入到裂缝,通过复位势理论和势的叠加原理得出了有关产能的压降方程;二是从裂缝流入到水平井段,通过对裂缝微元体的分析,得出有关裂缝参数的产能压降方程;三是气体从水平井段指端流入水平井段跟端,通过动量定理得出考虑井筒摩擦等影响因素的产能压降方程。根据得出的这三部分压降方程,考虑各部分间的连接条件,得出了含多条垂直裂缝的水平压裂气井的产能预测模型,通过编程求解了该模型,并分析了裂缝半长、裂缝条数以及裂缝在水平井筒中的位置对水平压裂气井产能的影响,从而为压裂后的产能评价及压裂井的优化设计提供了可靠的理论基础。

The percolation process is analyzed for fractured horizontal gas wells. The pressure drop caused by gas flowing from the reservoir to the bottom of the horizontal well is divided into 3 parts. The first is gas flows from the matrix of the formation to the fractures. With the reset potential theory and the potential superposition principle, the pressure drop equation is derived for production performance. The second is gas flows from the fractures to the horizontal section of the well. With the analysis of fracture microelements, the pressure-drop equation with fracture parameters is derived for production performance. The third is gas flows from the finger end to the root end of the horizontal section. With the momentum theorem, the pressure drop equation considering the influence of friction in the well bore is derived for production performance. Based on the 3 the pressure drop equations, considering the connecting conditions among the 3 parts, the productivity predicting model is developed for fractured horizontal gas wells with several vertical fractures. The model is solved by programming. And the influence of the fracture semi - length, the fracture number and the fracture position on the productivity of fractured horizontal gas wells is analyzed. So, it provides the sound theoretical ground for the productivity evaluation after fracturing and the optimized design of fracturing wells.