异常高压、特高产气井井底流压计算方法研究　　

Study on computing method of bottom-hole flow pressure of gas well with abnormal high pressure and high-productivity

罗志锋 王怒涛 黄炳光 尚立

LUO Zhifeng WANG Nutao HUANG Bingguang SHANG Li

油气藏地质及开发工程国家重点实验室·西南石油大学，四川成都　610500 川庆钻探公司钻采工程技术研究院，四川广汉　618300

State Key Lab of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China

异常高压、特高产气井井底流压对气井动态分析及管理至关重要。以高压高产气井井口压力动态为基础，基于质量守恒、动量守恒、能量守恒原理，综合考虑生产过程传热与井筒流动特征，建立了非稳态传热温度、压力耦合模型，编制了异常高压、特高产气井井底流压计算软件。将计算结果与现场实测井底流压进行对比分析表明：对特高产气井井底流压计算，常用的Colebrook、Jain及Chen摩阻因数计算经验公式适应性差，计算得到的流压易出现异常，表现在随着产量的增加，井底流压反而上升，甚至高于地层压力，但首先依据流体雷诺数大小判断流体所在的流动区域，再选用相应公式计算摩阻因数，可消除井底流压异常情况；特高产井产量高、流速快，考虑动能项比不考虑动能项井底流压要高出0.2~0.6 MPa左右，因此特高产气井井底流压计算必须考虑动能项。新模型计算的井底流压与实测值拟合误差小，精度高，具有较好的适用性。

Bottom-hole flow pressure（BHFP）of the gas well with abnormal high pressure and extra-high production is essential to the gas well dynamic analysis and management. According to wellhead pressure behavior of the gas well with high pressure and high production, based on mass conservation, momentum conservation and energy conservation, pressure-temperature coupling model for unsteady heat-transfer was established, and BHFP calculation software for gas well with abnormal high pressure and extra-high production were developed with considering the heat-transfer through the production process and the flowing behavior in the wellbore. The comparison results of BHFP obtained by calculation and field test showed that for BHFP calculation of extra-high production gas well, the applicability of conventional empirical calculation equations of friction resistance coefficient, such as Colebrook, Jain and Chen, are poor and the BHFP calculated by those equations is always abnormal. In other words, with the increase of production, the BHFP gained by those equations is increases and sometimes is even higher than the formation pressure. The abnormalities of BHFP could be eliminated by estimating the fluid flow region according to the Reynolds number and then choose the appropriate formula for calculating friction factor. For the extra-high production gas well, the high productivity and fast flowing rate causing that the calculated BHFP with considering the kinetic energy is about 0.2~0.6 MPa higher than that without considering kinetic energy. Thus, kinetic energy must be considered in the BHFP calculation process of the extra-high pressure gas well. The BHFP calculated by the new model was highly fitted with the measured value and the new model has better applicability.