水平气井气液两相管流压降预测

1.西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500;2.川庆钻探工程有限公司页岩气勘探开发项目经理部,四川成都610051;3.中国石化西南油气分公司采气四厂,重庆402160;4.中国石油西南油气田公司页岩气研究院,四川成都610051

油气田开发;排水采气;水平气井;两相管流;压降模型;持液率;压力转化;流型转变

Pressure gradient prediction of gas-liquid two-phase pipe flow in horizontal gas wells
LUO Chengcheng1,WU Ning1,WANG Hua2,LIU Yonghui1,ZHANG Teng2,WANG Benqiang2,WU Pengbo3,and LIU Jun4

1.State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation in Southwest Petroleum University, Chengdu 610500, Sichuan Province, P. R. China;2.Shale Gas Exploration&Development Project Department, CNPC Chuanqing Drilling Engineering Co. Ltd. , Chengdu 610051, Sichuan Province, P. R. China;3.The Fourth Gas Production Plant of SINOPEC Southwest Oil and Gas Field Branch, Chongqing 402160, P. R. China;4.Research Institute of Shale Gas, PetroChina Southwest Oil and Gas Field Company, Chengdu 610051, Sichuan Province, P. R. China

oil-gas field development; gas deliquification; horizontal gas wells; two-phase pipe flow; pressure gradient model; liquid holdup; pressure transition; flow pattern transition

DOI: 10.3724/SP.J.1249.2022.05567

备注

准确预测气井压降是气井动态分析、优化配产和排采工艺设计的基础.水平气井复杂的井身结构和流动规律,导致单一压降预测模型精度难以在宽泛的气液范围内满足工程需求.为开展模型优选及优化,基于环状-搅动、搅动-段塞和段塞-泡状3个流型转变点,提出垂直井筒持液率半经验模型;基于垂直管与倾斜管中持液率的对应关系,提出倾斜管中持液率预测方法,构建水平井气液两相管流压降预测新模型.研究结果表明,气井气液两相管流压降研究的核心是准确预测持液率;随着倾角增大持液率先增加后降低,倾斜管持液率可基于垂直管持液率随角度的变化关系计算得到;在所有对比模型中构建的新模型与气井生产测井数据的相对性能系数最小,表明模型能够满足工程计算精度要求.构建的新模型适用于不同产量范围的水平气井气液两相管流的压降预测,可为现场生产分析提供技术支撑.
Accurate prediction of pressure gradient in gas wells is the theoretical basis for dynamic analysis, optimization of production and deliquification technologies design. Due to the complicated wellbore trajectories and flow behavior of horizontal gas wells, the accuracy of any existing prediction model of pressure gradient alone is difficult to meet engineering requirement within a wide range of gas-liquid ratio. Hence, a semi-empirical model of liquid holdup in a vertical wellbore is proposed based on three transition points: annular-churn, churn-slug and slug-bubble transition points. Based on the corresponding relationship between liquid holdups in the vertical pipe and the inclined pipe, a prediction method of liquid holdup in the inclined pipe is proposed, and thus a prediction model of pressure gradient in horizontal wells is established. The results show that the most important step in predicting pressure gradient of gas-liquid two-phase flow is the accurate prediction of liquid holdup. The liquid holdup increases first and then decreases with the increase of the inclination angle. Liquid holdup in inclined pipes can be predicted based on the variation of liquid holdup in the vertical pipe with the inclined angle. The relative performance factor (RPF) of the proposed model is the smallest compared with the gas-well logging data of the reference models, indicating the new model can meet the requirements of engineering calculation accuracy. It is concluded that the new model can be applied to the prediction of gas-liquid two-phase pressure gradient in horizontal gas wells with different production ranges, and can provide technical support for field production analysis.
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