欠平衡钻井多相流模型评价分析

THE EVALUATION OF MULTIPHASE PHASE FLOW MODEL IN UNDER BALANCED DRILLING

为了给欠平衡钻井工程设计提供切实可行的井底压力预测模型,比较了利用均匀流动方法(Guo Boyun模型)、经验公式方法(Beggs-Brill模型、Orkiszewski模型、韩洪升和陈家琅模型)以及力学方法(Hasan-Kabir模型和修正的Ansari模型)建立的三类欠平衡钻井稳定流动模型。利用FORTRAN90分别对6个模型进行了编程求解,模拟了欠平衡钻井过程的环空气液两相流动规律,预测了充气液欠平衡钻井的井底压力。并把模型预测结果和现场施工数据以及全尺寸试验井试验数据进行了验证,分别指出了6个模型的预测精度。验证结果表明用力学方法建立的修正的Ansari模型的预测精度较高,可以满足欠平衡钻井井底压力设计的工程精度要求。推荐在欠平衡钻井工程设计中使用该方法,保证全过程的欠平衡钻井,实现欠平衡钻井的经济效益。

In order to provide a practical bottom hole pressure prediction model to the engineering design of under -balanced drilling (UBD) , six pressure prediction models which are established according to homogenous flow approach (Guo Boyun model) ,empirical correlation approach ( Beggs-Brill Model, Orkiszewski Model, Han Hongsh-en-Cheng Jialang Model) and mechanistic approach ( Hasan-Kabir model and modified Ansari model) are used to predict pressure drop in UBD. The six algorithms are implemented into a FORTRAN 90 computer program. Gas-liquid two-phase flow in annuli in UBD is simulated by the six models and bottom hole pressure is predicted in gasified-liquid UBD. The prediction results are validated with field data and full-scale experimental data. The predictions precision of the models is presented. The comparative analysis shows that modified Ansari model better pressure prediction in under-balanced drilling and it satisfies the accuracy demand of under-balanced drilling. The method is recommended in the design of under-balanced drilling to maintain full under-balanced status and economic benefit target of under-balanced drilling is obtained.