Study And Evaluation Of The Authigenic Gas Foam Gel Plugging System

With majorities of water flooding oil fields entering the late development stage,the reservoir heterogeneity is becoming serious,especially in reservoirs that have active edge-basal ground water.Large-dose and multi-slug plugging methods are widely used domestically to control water cut and stabilize oil production,but cost a lot.Concerning this problem,study of the authigenic gas foam gel plugging system is proposed in this paper.The system can expand spontaneously without an external air source,bringing high in-situ volumn expansion multiple,simple operation technique and selective water shutoff.Add expansive agent to the chromic gel in laboratory,then ultilize gas from this reaction to form foam,a new system with the property of foam and gel can be made.Through mono-factor experiments,the optimum polymer component of water medium dispersible type polyacrylamide emulsion was selected.By means of orthogonal experiments,the optimal concentration of different components like polymer,cross-linking agent and expansive agent,was determined: 0.40% polymer+0.36% cross-linking agent+0.6mol/L expansive agent.Under circumstance of pH 6.5~7.4,60? and gel time 28 hours,this gel system got an expansive rate of more than 150%.Factors such as components concentration,pH value,salinity etc,were evaluated on gel and stability performance of the system,showing that this foam gel system possess strong controllability,wide pH range and good salt-resistant ability.Plugging performance was remarked through the sand-filled pipe physical model,good plugging properties and long water-control validity.In this paper,the field process of plugging on Zhou 43 A well was designed,whose result was good and effective.