非线性渗流下低渗气藏压裂井产能评价

Production Evaluation of Fractured Wells in Low Permeability Reservoirs with Nonlinear Flow

熊健 邱桃 郭平 魏斌

Xiong Jian Qiu Tao Guo Ping Wei Bin

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; 中国石油新疆油田公司采油二厂, 新疆克拉玛依 834008

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University), Chengdu, Sichuan, 610500, China; No.2 Oil Production Plant of Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang, 834008, China

气体渗流受启动压力梯度、滑脱效应和应力敏感等多个因素影响,以前的研究没有综合考虑以上因素。针对低渗气藏渗流特征,根据气井压裂后气体渗流规律的变化,基于稳定渗流理论,建立了综合考虑启动压力梯度、滑脱效应和应力敏感等因素的低渗气藏有限导流垂直裂缝井产能预测模型,并利用该模型分析了启动压力梯度、滑脱效应、渗透率变形系数、地层污染等对低渗气藏压裂井产能的影响。研究表明:随着启动压力梯度和应力敏感的增大,气井产能呈近线性下降趋势,其中应力敏感的影响程度更大;随滑脱效应的增大,气井产能呈近线性上升趋势;在低渗气藏压裂参数设计中,增加裂缝长度比增加裂缝导流能力更重要,一定裂缝长度下存在一个最佳的裂缝导流能力;污染带半径增大和污染带渗透率降低都可使气井产能下降,下降幅度随着污染带半径增大和污染带渗透率降低而增大。

The main factors affecting gas flow include start-up pressure gradient,slippage effect and stress sensitivity,etc.According to the characteristic of low permeability gas reservoir,and the change of fluid flow rule after fracturing treatment,a gas well productivity prediction model was established for the finite conductivity vertical fracture wells based on stable seepage theory while taking the influence of the start-up pressure gradient,slippage effect and stress sensitivity into account.The influences of such factors as slippage,start-up pressure gradient,stress sensitivity and formation damage,etc.on productivity were analyzed.Results showed that the gas well productivity would decrease almost linearly with start-up pressure gradient and stress sensitivity,and the major decrease was caused by stress sensitivity.The gas well productivity increased with slippage effect linearly.In the fracturing design of low-permeability gas reservoirs,to increase fracture length would be more important than to increase fracture conductivity,and for a given fracture length,there would be an optimum fracture conductivity.Formation damage would reduce well productivity and the reduction would increase as formation damage radius increase and permeability decrease.

国家科技重大专项"深水扇储层气田产能和开发指标预测研究"(编号:2008ZX005056-02-02-03)、西南石油大学研究生创新"非线性渗流下低渗气藏产能特征研究"(编号:GIFSS0701)部分研究成果

https://doi.org/10.3969/j.issn.1001-0890.2012.03.019