基于数值模拟的电缆地层测试泵抽油气纯度预判

Oil-Gas Sampling Purity Prediction Based on Numerical Simulation for Modular Dynamic Formation Tester

模块化电缆地层测试器作业时,近井地带受钻井液侵入影响,泵出流体先为钻井液滤液后为地层流体。但很难估计地层油气突破体积及达到某一泵抽纯度所需要的泵抽量,而这些参数对泵抽的指导、优化及作业时间的合理分配具有重要意义。采用数值模拟方法优化测井,通过建立高精度(厘米级)网格模型,确定影响油气突破及泵抽纯度的主要机理,形成不同探针作业时的油气突破体积预测图版及满足PVT实验流体纯度要求可取样体积预测图版,利用图版可提高泵抽时效性。成果在最新完钻的重点风险探井中进行验证,取得较好的应用效果。

During modular dynamic formation tester(MDT)operation,the near wellbore area has been affected by mud invasion,and the pumped fluid is the sequence of mud filtrate first and formation fluid later.In the process of MDT pumping operation,it is difficult to estimate the breakthrough volume of oil and gas,and the pumping volume required to achieve a certain pumping purity.These parameters are of great significance to the guidance,optimization and reasonable operation time allocation of pumping.Based on the sampling simulation with an extremely high precision grid(centimeter-level),we confirmed the main parameters affecting in-situ fluid breakthrough and formed a series standard breakthrough and PVT sample accepted predict charts of different probes,based on the charts,operation efficiency can be improved.MDT are used in the wells recently drilled to verify the mobility correlation versus petrophysics parameters and the fluid breakthrough charts as the outcome from this study and achieved good application results.