坪北特低渗透油藏启动压力梯度实验与应用

Experiment and application of start pressure gradient of PingBei ultra-low permeability reservoir

坪北油田属低孔、特低渗、低压、低产油藏,目前正处于中高含水开发阶段,面临诸多特低渗透油藏普遍存在的问题,油田高效开发难度加大。分析了启动压力梯度对储层物性的影响和流动系数之间的关系,并对比了单项启动压力梯度和两相启动压力梯度的不同,研究了启动压力梯度对极限注采井距等开发因素的影响规律,并提出了相应的技术对策。结果表明,特低渗油藏必须明确启动压力梯度变化规律,从而选择合适注采压差,建立油水井间有效驱替,才能进一步改善开发效果。

Pingbei Oilfield is a low porosity,ultra-low permeability,low pressure and low production reservoir,which currently faces many common problems for this kind of reservoir in the middle and high water-cut development stage,and it has many difficulties in the efficient development of this oilfield.This paper analyzes the influence of starting pressure gradient on reservoir physical properties and its relationship to the flow coefficient and make a comparison between the starting pressure gradient and the two-phase starting pressure gradient.In addition,the influence of starting pressure gradient on the limit well spacing and other related factors influencing the oil development are studied,and the corresponding technical countermeasures are put forward.The results show that the law of starting pressure gradient must be studied in ultra-low permeability reservoirs,the proper pressure difference between injection and production should be selected,effective displacement pressure difference should be established,and the development efficiency should be improved.