珠江口盆地(东部)海相砂岩油藏在生产井改造技术及其实施效果

Producing well reconstruction technique and implementation from marine sandstone oil fields in the eastern Pearl River Mouth basin

海相砂岩油田进入特高含水期开发阶段后,将面临综合含水高、采油速度下降、剩余油分布零散、井网加密余地小、可持续开发难度大等问题。以珠江口盆地(东部)西江、陆丰及惠州等典型海相砂岩油田为例,总结了海相砂岩老油田特高含水期面临的工程技术问题,提出了一系列在生产井改造技术:通过定向井二次完井"合转分"改造减少层间干扰,实现迭瓦式层状油藏细分层系开采;通过水平井MRC储层改造,实现相对低渗透层或块状砂岩油藏泥灰质条带区域油藏泄流面积增大及地层横向导流能力提高;通过水平井分段储层改造,解放水平井段中低渗高含油井段并实现降水增油效果;通过井下油水分离改造,实现一井多用、节能减排及为低含水井置换提液增产空间;通过区域井组合"自流注水"井组改造,建立有效注采系统并补充驱动能量;通过水平井向直井的井型改造,实现挖潜水平井穿越过路油层及一井多用的井筒功效。所提出的在生产井改造技术在珠江口盆地(东部)西江、陆丰及惠州等海相砂岩油田挖潜中成效显著,对同类特高含水期老油田的可持续开发具有重要的借鉴意义。

After entering into the ultra-high water cut development stage,marine sandstone oil fields were facing the problems such as high water cut,production rate decreasing,the scattered remaining oil distribution and narrow room for well pattern thickening,which make the sustainable development more difficult.For Xijiang,Lufeng and Huizhou marine sandstone oil fields in Pearl River Mouth basin （eastern part） of the South China Sea,the engineering technical problems encountered at ultra-high water cut stage of mature sandstone oilfields are summarized so as to propose a series of producing well reconstruction techniques.By recompletion of the commingled directional wells,the producing well could easily produce from individual layers separately,and the interferences between different permeable payzones are reduced so as to produce from different layers in the stratified reservoir.By MRC formation reconstruction for horizontal wells,the drainage area gets larger and the formation lateral flow conductivity enhances in relatively low permeability layers or marlaceous strip area of massive sandstone reservoir.By segregated formation reconstruction of the horizontal wells,the crude oil in the mid low permeability area with high oil saturation around horizontal segments are produced at lower water cut and higher oil production.With down hole oil and water separation,increasing the production of midlow water cut wells become possible by re injecting produced water into water saturated sandstone which greatly save energy and reduce emission.The effective injection-production system is established to supplement the driving energy by dump injection reconstruction of different well groups.The horizontal wells are reconstructed to produce the upper passing layers by plugging the horizontal segment and re-perforating the upper directional segments,which greatly improve the effectiveness of wellbore.The producing well reconstruction techniques proposed here are applied to the marine sandstone of Xijiang,Lufeng,and Huizhou marine sandstone oil fields in Pearl River Mouth basin （eastern part） of the South China Sea and achieve good effect,which show great significance for sustainable development of the similar oilfields at ultra-water cut development stage.