提高低渗碳酸盐岩储集层动用程度技术

Technologies for improving producing degree of low permeability carbonate reservoirs

让纳若尔油田为大型低孔低渗复杂碳酸盐岩油藏,储集层非均质性强,由于早期衰竭式开发、中方接管后提高采油速度,地层压力下降快,油田递减逐年增大。在大量生产测试资料统计的基础上,根据产液强度和吸水强度把储集层分为动用好、动用较好、动用差、未动用等4类,其中未动用和动用程度差的储集层占50%以上。提高储集层动用程度,改善注水开发效果是油田综合调整的主力方向。采取分层系开采、分层酸压、分层注水、井网加密、气举采油等多个储量动用对策,在平面上完善注采对应关系,提高平面注水波及面积,在纵向上改造弱动用层,提高水驱波及系数。经过3年的实施应用,注水开发效果得到明显改善,主力油藏递减率下降10%以上,储量动用程度提高12%,油田采收率提高4.3%。

Zanarol is a giant carbonate oil field with low permeability and high heterogeneity reservoirs. The reservoir pressure drops quickly and the production declining rate increases due to the previous depletion development and fast production after CNPC engaged in. Based on producing tests, the reservoirs can be classified into four types according to producing and injection intensities, better producing, good producing, lower producing and no producing, and over 50% reservoirs have no or lower production. Improving producing degree and water flooding effect is the orientation for next development adjustment. Several measures for improving producing degree are implemented, including separate zone producing, separate zone fracturing stimulation, separate zone water injection, well pattern infilling, and gas lift, as well as increasing plane sweep efficiency by ameliorating correlation between injection and production and increasing vertical sweep efficiency by stimulating zones with lower production. After 3 years of application, the production declining rate of main pools decreases by 10%, the producing degree increases by 12%, the recovery factor increases by 4.3%, and the water flooding development improves greatly.