各向异性双重介质两相非达西椭圆渗流

NON-DARCY FLOW OF TWO-PHASE FLUID THROUGH ANISOTROPIC LOW-PERMEABILITY DOUBLE-POROSITY MEDIA FOR VERTICALLY FRACTURED WELL

建立了各向异性双重介质油藏中垂直裂缝井两相非达西椭圆渗流数学模型 ,用有限差分法求得了解 ,并进行实例分析。结果表明 :吸渗使前缘推进速度减慢 ,使油井见水晚 ;非达西流使前缘推进速度加快 ,使油井见水早 ;注入率越大 ,前缘推进速度越快 ,油井见水越早 ,注水开发这种油藏时 ,见水前注入率不能太大以充分发挥吸渗作用 ,见水后可适当增大注入率以减弱非达西流的影响。

Amathematical model for Non Darcy flow of two phase fluid through anisotropic double porosity media with a vertically fractured well working is established. Numerical solution to the model is presented by using finite difference method. An example is given and discussed. Distribution of water saturation in the direction of radius, maximum permeability and minimum permeability and changeof iso-saturation level with time are obtained. Results show that: (1) the iso saturation level moves faster and water breaks through the well sooner in the direction of the larger permeability than in that of the smaller; (2) the imbibition makes velocity of the level movement become smaller and time of water breakthrough get larger; (3) the level moves and water breaks through the well faster in Non Darcy flow than that in Darcy flow; and (4) the larger the injection rate is, the faster the level moves and the sooner water breaks through the well. The injection rate mustn't be too large before water breaks through the well so that the imbibition can play an important role in water-flooding development of the low permeability double porosity reservoir. And the injection rate should be raised appropriately after water breaks through the well in order to weaken the influence of Non Darcy flow on the development.