低渗透油藏井网优化技术研究——以河135断块区为例

低渗透油藏受特殊的成藏条件、沉积环境影响,具有孔隙结构复杂、孔喉半径细小,油藏渗透率低,一般小于50×10-3μm2;储层非均质严重,平面渗透率级差最高达几百个数量级;驱替压力大、存在一定的启动压力;天然裂缝发育且存在人工裂缝等特点;因此,在不同渗透率级差下,如何建立起有效的驱替半径,建立合理、经济的井网密度,对提高低渗油藏水驱油效率及采收率,提高低渗透油藏的开发水平具有十分重要的意义。以低渗透油藏河135断块区为例,通过系统地对河135断块区储层非均质、裂缝进行研究,建立储层非均质—裂缝模型,在地质研究的基础上,针对不同渗透率级别、不同沉积相带,确定了不同的技术极限井距及经济合理井距,并考虑裂缝推出了适合的井网形式。

A study on well pattern optimization technique in the low-permeable oil reservoir——taking He 135 fault block as an example

Under the influences of peculiar reservoir-forming condition and sedimentary environment,the low-permeable oil reservoir has some characteristics,such as the complicated spore configuration,the exiguous pore throat,the low permeability,generally less than 100×10-3μm2,the serious reservoir heterogeneity,the plane permeability varies greatly,the big displacement pressure,existing certain starting pressure,natural fracture growth and existing man-made fracture,etc.Therefore how to establish the effective displacement radius,and the reasonable and economic well density with different permeability,it's important to raise the oil-water displacement efficiency,recovery efficiency factor and exploitation level of the low-permeable oil reservoir.This paper takes the He 135 fault block as an example,studies systematically reservoir heterogeneity and crack of the He 135 block,and founds the reservoir heterogeneity-crack model.Based on the geological study,conform the different technical limited well spacing and economic and reasonable well spacing with different permeability and sedimentary microfacies,and proposing the befitting pattern considering crack.