新场气田须家河组地层水回注可行性研究

Feasibility Study on Formation Water Re-injection in Xujiahe Group in Xinchang Gas Field

新场气田开发过程中的地层水产出问题日益凸显,处理后达到外排标准的成本高。文章从气藏地质特征、采出水水质分析、与地层水的配伍性分析、回注层储集能力等方面研究了新场气田须五段产出地层水回注的可行性,并在室内开展了回注水对储层岩心的伤害试验。结果表明:须五段巨厚的泥页岩砂岩互层及层内水平缝发育特征,有着较大的储水能力;采出水成分复杂,但经预处理后与地层水的配伍性好;对岩心的伤害小,回注后储层渗透率仅下降1.23%;储层中的砂岩层具有中等偏强水敏、弱碱敏特征,泥页岩层具有中等偏弱水敏、弱碱敏特征。

The formation water treatment problem in the development of Xinchang Gas Field is becoming more and more prominent,and the cost of the treatment to reach the efflux standard is high.This paper studied the feasibility of formation water injection in the fifth section of Xinchang Gas Field from the aspects of gas reservoir geological characteristics,produced water quality analysis,compatibility analysis with formation water,and reinjection layer capacity,etc.The damage test of the re-injection water to the reservoir core was carried out indoor.The results showed that the interbedded and interbedded horizontal fractures of the mud-shale and sandstone of the wuduan section with great thickness have great water storage capacity.Produced water had a complex composition,but after pretreatment it had good compatibility with formation water.The damage to the core was small,and the reservoir permeability only decreased by 1.23%after reinjection.The sandstone layer in the reservoir had medium to strong water sensitivity and weak alkali sensitivity,and the mud shale layer had medium to weak water sensitivity and weak alkali sensitivity.