裂缝性低渗气藏水平井不稳定产量递减探讨

发布时间：2018-12-27 21:00

【摘要】：针对气体在低渗储层中低速流动时存在启动压力梯度的问题,开展了渗流模型建立、求解及定性分析研究。采用低速非达西渗流机理,建立了考虑启动压力梯度的裂缝性低渗气藏水平井不稳定渗流模型,求解了数学模型并绘制了水平井产量递减典型曲线。该渗流模型最终求取的是定压生产条件下低渗气井的不稳定产量解,为采用图版拟合法评价储层参数提供了理论依据。启动压力梯度等相关参数对递减曲线的影响分析表明,启动压力梯度越大、储层物性越差,流动越困难,水平井产量越低,产量递减曲线位置越低;弹性储容比越小,基质窜流发生越早,产量导数曲线上的下凹部分持续时间越长,下凹程度越深;窜流系数越小,产量导数曲线上的下凹部分出现时间越晚,窜流越难发生。
[Abstract]:In order to solve the problem of starting pressure gradient in low velocity flow of gas in low permeability reservoir, the seepage model is established, solved and qualitatively analyzed. The unstable percolation model of fractured low permeability gas reservoir horizontal well considering starting pressure gradient is established by using low speed non Darcy seepage mechanism. The mathematical model is solved and the typical curve of production decline of horizontal well is drawn. The percolation model finally obtains the unstable production solution of low permeability gas wells under the condition of constant pressure production, which provides a theoretical basis for the evaluation of reservoir parameters by using the pattern fitting method. The effect of starting pressure gradient and other related parameters on the decline curve shows that the greater the starting pressure gradient, the worse the reservoir physical property, the more difficult the flow, the lower the horizontal well production and the lower the position of the production decline curve. The smaller the elastic storage volume ratio is, the earlier the matrix channeling occurs, the longer the concave part of the yield derivative curve lasts, the deeper the concave degree is, and the smaller the channeling coefficient is, the later the concave part appears in the yield derivative curve, and the more difficult the channeling occurs.
【作者单位】：西南石油大学"油气藏地质及开发工程"国家重点实验室;中国石油川庆钻探工程公司地质勘探开发研究院;中海石油湛江分公司;
【基金】：国家重点基础研究发展计划(973计划)(2014CB239205)
【分类号】：TE328

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