摘要
致密气藏存在启动压力和应力敏感等特殊渗流机理,对气井产量有较大影响,由于现有产量预测模型大多未同时考虑两者影响,且启动压力梯度等关键参数难以准确获取,导致其不适用于致密气藏气井的产量预测。在顶底封闭的均质无限大致密气藏渗流模型基础上,建立了考虑启动压力梯度和应力敏感的致密气藏直井产量预测模型,绘制了产量递减理论图版,提出了基于产量历史数据获取模型关键参数来修正产量预测模型、提高产量预测精度的图版拟合方法。由敏感性因素分析可知,气井产量前期主要受应力敏感影响,应力敏感性越强则产量递减越快;后期主要受启动压力影响,启动压力梯度越大则气井生命周期越短;当无因次渗透率模量大于0. 000 1或无因次拟启动压力梯度大于0. 001时,气井产量快速递减,若不考虑启动压力和应力敏感将导致产量预测误差较大。苏里格致密气藏实例验证表明,该模型预测精度较高,应用效果较好。
There are special seepage mechanisms,such as starting pressure and stress sensitivity in tight gas reservoirs,which have a great impact on gas well production.Most of the existing production forecasting models do not consider the influence of both,and the key parameters such as starting pressure gradient are difficult to obtain accurately,so it is not suitable for production forecasting of tight gas wells.Based on the homogeneous and infinitely tight gas reservoir seepage model with closed top and closed bottom,the prediction model of tight gas production in tight gas reservoir considering the starting pressure gradient and stress sensitivity is established.The theoretical chart of yield decline is drawn and the historical data based on yield is proposed.The key parameters of the model are used to correct the yield prediction model and improve the yield prediction accuracy of the plate fitting method.According to the analysis of key influencing factors,the gas well production is mainly affected by stress sensitivity in the early stage.The stronger the stress sensitivity,the faster the production declines.The later stage is mainly affected by the starting pressure.The larger the starting pressure gradient,the shorter the life cycle of the gas well.When the permeability modulus is greater than 0.000 1 or the dimensionless pseudo-starting pressure gradient is greater than 0.001,the gas well production decreases rapidly.If the starting pressure and stress sensitivity are not considered,the yield prediction error will be large.The application of the Sulige tight gas reservoir shows that the gas well production prediction accuracy is higher and the application effect is better.
作者
陈中华
刘先山
寗波
姜柏材
向祖平
秦正山
唐欢
常小龙
Chen Zhonghua;Liu Xianshan;Ning Bo;Jiang Bocai;Xiang Zuping;Qing Zhengshan;Tang Huan;Chang Xiaolong(College of Petroleum and Natural Gas Engineering, Chongqing University of Science and Technology, Chongqing,401331, China;China National Petroleum Corporation Science and Technology Research Institute, Beijing, 100083, China)
出处
《天然气与石油》
2018年第6期48-53,76,共7页
Natural Gas and Oil
基金
国家科技重大专项"气井
区块和气田递减规律分析方法建立与软件编制"(2016 ZX 05047-004-004)
重庆市基础与前沿研究计划项目"页岩气藏体积压裂水平井非线性渗流理论及流-固耦合综合模型研究"(cstc 2015 jcyj A 90014)
关键词
致密气藏
产量预测
启动压力梯度
应力敏感
Tight gas reservoir
Production prediction
Starting pressure gradient
Stress sensitivity
