低渗透油藏七点井网的有效动用程度

为表征剩余油的分布规律,以及井网后期加密调整提供理论参考,利用叠加原理,求解考虑启动压力梯度的七点井网稳态压力方程,用压力公式推导流函数模拟井网单元间的流线分布.结果表明:考虑启动压力梯度时井网单元内存在流体流动区和不动区,定义为流动面积与井网单元面积比值的有效动用因数随储层参数变化而变化,启动压力梯度越大,有效动用程度越低,增加储层有效渗透率(如酸化、压裂)、增大注采压差和缩小注采井距能提高有效动用因数;储层物性较差时,缩小井距是提高有效动用因数的有效方式,储层物性较好时增大生产压差效果更好.

Effective development degree for seven-spot well patterns in low permeability reservoirs

In order to ascertain the distribution of remaining oil and provide important reference for infilling well in practice,by applying the principle of superposition,the steady-state pressure distribution for infinite seven-spot well patterns can be obtained for low permeability reservoir with TPG,from which streamlines distribution was derived.The result shows that effective development coefficient(SDC),which is the ratio of flowing zone to whole zone,is determined by multi-parameters: the SDC decreases with TPG increasing,but increases with the effective permeability of formation(such as acid treatment and hydraulic fracture) increasing,with injection-production differential pressure increasing,and with the shorter intervals of wells.The analysis of variation sensitivity of SDC shows that when the permeability is small,it is a better choice to shorten well space to improve SDC;otherwise increase differential pressure.