欠平衡钻井储层压力动态模拟及数据处理

欠平衡钻井期间,由于负压差的存在,使地层流体在钻进的时候就源源不断地流入井筒,从而使井筒周围的地层压力发生变化,对以后的生产和测试带来很大的影响。在一定的假设参数条件下,建立了一套地层压力变化的数学模型及其相应的边界条件。由于在钻进过程中,储层的裸露段随钻进时间不断变化,因而其内边界条件也不断变化,使用解析方法求解该模型变得十分困难。故采用有限差分法,用矩阵计算软件编程计算了地层压力随钻进时间变化而变化的情况,并把结果导入可视化工具,将压力变化以直观的图形表示出来,为这方面的学者在实际考虑这一过程时提供了一定的理论和实践参考。

Simulation of Reservoir Dynamic Pressure and Data Processing During Underbalanced Drilling

During UBD, oil or gas in reservoir formation flows continuously to the well ?bore because the pressure of the circulating drilling fluid is lower than the pore pressure of the target formation. So the pore pressure around the well?bore goes down persistently in this time. It must make a deep difference on the subsequent testing and production. In this paper, a mathematical model of formation pressure variation and corresponding boundary condition were given. But it is very difficult to solve this model by using analytical method. Finite Difference Method was adopted and a matrix calculating tool was used to calculate the formation pressure with time varying. The calculation result is shown with intuitive pattern.