姬塬油田长8油藏裂缝发育特征及对井网加密方式的影响

Fracture Development Characteristics of Chang 8 Reservoir in Jiyuan Oilfield and Its Impact on Well Pattern Encryption

本文通过钻井岩芯、成像测井、镜下鉴定资料,并结合盆地的构造演化历史对该地区裂缝发育特征及其成因进行了综合研究。由于裂缝的大量存在,使得长8超低渗透储层具备相对高渗带,在注水开发过程中,裂缝一方面会增强注水井的吸水能力和采油井的生产能力;而另一方面,如果注水控制不当,水会沿着裂缝快速推进,使裂缝主方向上的油井水淹,而裂缝侧向井由于注入水难以波及则见效缓慢或者不见效,油井产能递减大。裂缝性油藏在实施加密调整时,要依据裂缝主向注水,侧向加密的方式原则,通过缩小排距加密,促进有促进油井见效。2017年~2018年在罗1区长8油藏开展了加密调整试验,新钻加密井40口,目前已取得了初步效果,预测采收率提高3.4%左右。

The characteristics of the fractures in the reservoir of Jiyuan Oilfield are studied by drilling cores,logging of microscopic identification data,combined with the tectonic evolution of the the Ordos Basin.Because there are a lot of cracks,making the Chang 8 reservoirs have relatively low permeability reservoir with high permeability zone.In waterflooding process,the fractures on the one hand will increase the water absorption capacity of injection wells and the production capacity of producing wells.On the other hand,if not properly controlled water,the water will quickly advance along the fracture,the wells in the main direction of the fissures are seriously flooded,while those on the lateral are short of fluild supply,diminishing oil production.When tight adjustment is applied in fractured reservoirs,it is necessary to reduce row spacing and infill according to the principle of main injection and lateral infilling of fractures,so as to promote the effectiveness of oil wells.From 2017 to 2018,infilling adjustment tests were carried out in Chang 8 reservoir of Luo 1 area.Forty infilling wells were newly drilled.Preliminary results have been achieved and the predicted recovery rate has increased by about 3.4%.