多阶梯水平气井渗流与井筒管流耦合模型

COUPLING MODEL OF THE SEEPAGE AND WELLBORE CONDUIT FLOW FOR MULTI-STEPPED HORIZONTAL GAS WELL

考虑阶梯水平井穿越3个独立气层的情况,根据质量守恒原理和动量定理,结合实际气体的状态方程,利用采气指数的概念,建立了裸眼完井方式下多阶梯水平气井渗流与井筒变质量管流耦合的数学模型并编制了相应的计算程序进行求解。利用该模型,可以求解阶梯水平气井井筒沿程压力分布及产量分布,为阶梯水平气井的生产系统分析提供了理论依据。模拟计算表明,阶梯水平井在钻遇多个气层时,先钻遇物性最好的储层所得到的径向产量高于先钻遇物性最差的储层。

Considering the stepped horizontal gas well across three independent gas layers and on the bases of the mass conservation principle and momentum theorem, the mathematical model coupling the formation seepage and wellbore variable mass conduit flow for the multi-stepped horizontal gas well is established under the condition of open hole completion and furthermore the corresponding calculation is programing and finally the solutions are sought with the help of the concept of gas production index. By means of the model, both distributions of on-way pressure of the wellbore and production can be got, thus the theoretical basis for the production system analysis is presented. The simulation calculation shows that when this kind of horizontal well penetrating many gas layers, the lateral production from firstly drilled layer with the best physical properties is higher than that of the firstly drilled one with the worst physical properties.