特低渗透油藏启动压力对油田开发的影响

特低渗透油藏由于孔喉结构的特殊性而导致流体在微小孔喉中呈现微尺度流动效应,即非达西渗流。利用岩心实验及数学模拟方法详细研究了特低渗透油藏启动压力梯度及其对油田开发的影响。研究结果表明:启动压力梯度与渗透率之间呈幂函数关系;启动压力梯度对水平井产量影响小于直井;在相同的含水饱和度下,具启动压力的油藏含水率上升较快且容易发生指进。非达西渗流将增大特低渗透油藏注水开发的难度。

Influence of Startup Pressure on Oilfield Development in Ultra-permeability Reservoir

Fluid flow through micro pore throat presents micro-scale flow effect, which is non-Darcy flow because of the peculiarity of pore throat structure in ultra-permeability reservoir. Startup pressure gradient and its influence on oilfield development were studied by using core testing and mathematical simulation. The results show that there is power function relationship between startup pressure gradient and permeability, the influence of startup pressure gradient on production of horizontal wells is less than that of straight wells. Under the same water saturation, water percentage of oil reservoir with startup pressure increases quickly, and the fingering will emerge easily. Non-Darcy flow will increase the difficulty of waterflooding in ultra-permeability reservoir.