窄河道致密气藏采出水回注可行性研究——以中江气田为例

Feasibility study of for mation water reinjection in narrow channel tigh tgasreser voirs:Take Zhongjiang Gas Fiel dasan example

随着中江气田快速上产,气田面临着巨大的采出水处理压力。而回注是最为快捷、经济且环保的采出水处理手段,但对于以窄河道致密砂岩气藏为主要开发对象的中江气田,其地质条件相对复杂,回注选井、回注量估算等都存在一定难度。根据中江气田窄河道储层特征及气井井型特征,从地质、工程、环境3个方面开展回注条件研究,建立了回注选井原则,优化了回注量计算公式。以单井为实例分析回注可行性,论证回注井储层发育情况、地层封盖能力、最大注水量、注入压力、地层水配伍性。回注试验表明试注情况与理论计算较为一致,所选气井具有良好的回注潜力,表明窄河道致密砂岩气藏采出水回注具有可行性。

With the rapid production of Zhongjiang gas field,the gas field faces great pressure of produced water treatment.Reinjection is the most efficient,economical and environmentally friendly means of produced water treatment.However,the geological conditions of Zhongjiang gas field,which is mainly developed by narrow channel tight sandstone gas reservoir,are relatively complex,and there are some difficulties in reinjection well selection and reinjection volume estimation.In this paper,according to the narrow channel reservoir characteristics and gas well type characteristics of Zhongjiang gas field,the reinjection conditions were studied from geology,engineering and environment,the well selection principle of reinjection was established,and the calculation formula of reinjection volume was optimized.Taking a single well as an example,the feasibility of reinjection is analyzed,and the development of reservoir,formation capping ability,maximum injection water volume,injection pressure and formation water compatibility of the reinjection well are demonstrated.The injection test results show that the test results are consistent with the theoretical calculation,and the selected gas well has good injection potential,which indicates that the produced water injection of tight sandstone gas reservoirs in narrow channel is feasible.