特低渗透油藏基质-裂缝耦合非定常流动规律研究

Study on matrix-fracture coupling unsteady flow in extra-low permeability reservoirs

针对特低渗透油藏具有人工压裂裂缝的特点,首先建立了特低渗透压裂油藏三区物理模型,并在此基础上,依据等压椭球面理论,导出了特低渗透油藏有限导流裂缝井井底压力表达式,并对三区有限导流裂缝井的产能和影响因素进行了分析讨论。结果表明:缝长对产量的变化有着重要影响,较长的裂缝其产量的递减比较明显;较厚的油层其产量的递减较快。该方法对特低渗透油藏水力压裂井的开发具有重要的理论和现实意义。

Extra-low permeability reservoirs usually have artificial fractures, so that a physical model has been built accordingly for the Third District. Based on equipressure ellipsoid theory, the expression of bottom-hole pressure in finite conductivity vertical fracture wells of extra-low permeability reservoirs has been derived, and the deliverability and influential factors of finite conductivity vertical fracture wells are analyzed and discussed for the Third District. The result shows that fracture length has an important impact on production: the longer the fracture is the more obvious the production decline appears, and the thicker the oil reservoir is the faster the production decline is. This method is of important theoretical and practical significance for hydraulic fracturing wells in extra-low permeability reservoirs.