常压页岩气水平井压后排采控制参数优化

OPTIMIZATION OF THE CONTROLLING PARAMETERS OF THE POST-FRAC FLOWBACK AND PRODUCTION FOR NORMAL-PRESSURE SHALE-GAS HORIZONTAL WELLS

为了精细描述页岩气水平井较长的排采周期,基于商业模拟器Eclipse的双孔双渗模型,将压裂过程等效为注水过程,并进行地层压力场及饱和度场的初始化,以消除常规压裂井数值模拟忽略压裂施工对排采影响的局限性。基于渝东南某常压页岩气数据,建立了多段压裂水平井压后排采模型,并优化了排采参数。结果表明:压后立即采取返排措施,排采压差为12 MPa以上,初期日排液量不小于50 m3,压裂液同步彻底破胶,常压页岩气水平井排采效果较好。以此为基础,指导该区2口水平井的压后排采,取得了较好的效果。

In order to finely characterize the long-period flowback and production of the horizontal well in a shale gas reservoir,on the basis of the dual-porosity and dual-permeability model of the commercial simulator Eclipse,the fracturing process was equivalent to one of the water injection,the initializations were conducted for the formation pressure and saturation fields so as to eliminate the limitations of ignoring the influences of the fracturing operation on the flowback and production for the numerical simulation of the conventional fractured wells. Based on the data of the normal-pressure shale gas reservoir in Southeast Chongqing,the model of multi-fractured horizontal well was established for the post-frac flowback and production,and moreover the corresponding parameters were optimized. The results show that the rapid flowback after the fracturing,the differential pressure is be above 12 MPa,and the initial daily liquid production is no less than 50 m3,the fracturing fluid is broken synchronously and completely,thus much better operation effects can be achieved for the normal-pressureshale-gas horizontal wells. Onthe parameters stated above,two-horizontal-well post-frac flowback and production were guided and furthermore pretty better effects were obtained in the end.