中等润湿性在油气钻探和开发中的应用

Application of Intermediate Wettability in Oil/Gas Drilling and Oil Recovery

分析了润湿性在油气钻探与开发中的作用,认为中等润湿性有利于提高钻井液的稳定性、有利于降低钻具的摩阻和提高机械钻速,有利于降低油气层微粒运移损害和提高原油采收率。通过工作液或其滤液使油藏岩石表面转化为或保持中等润湿性,从而提高油气采收率。按照该技术思路,提出了钻井完井液不仅应该满足钻井正常作业和保护油气层的要求、还应该有利于提高油气井产能的观点,并以无机或有机正电胶、聚合醇和聚合物为主剂,开发了无机或有机正电胶双聚钻井液体系。现场应用表明,该体系具有独特的流变性、优良的润滑性及稳定井壁作用,以及显著的保护储层和提高油气采收率功能。

This paper investigates the function of intermediate wettability in oil drilling and recovery, and draws a conclusion that the intermediate wettability is advantageous to drilling fluid stability, drilling friction reduction, enhancing ROP, formation damage control, and enhancing oil recovery. The novel technology called neutral working fluids is proposed from the viewpoint of enhancing oil recovery. The key technique is to keep reservoir rocks under the condition of intermediate wettability by chemical means, namely working fluids or their filtrates. It is suggested that drilling and completion fluid should not only meet the needs of drilling engineering and formation damage control, but favor to increasing well deliverability. A new drilling and completion fluid named inorganic or organic positive gel/polyol/polymer systems are developed and applied in oil field. The testing results show that, with the coordination of inorganic or organic positive gel/polyol and polymer, the systems not only holds unique rheology, excellent lubricity, wellbore stability, formation protection, but holds the advantage of increasing oil and gas deliverability because of the wettability alteration from strong water wetting to intermediate wetting. In the end, this paper proposes the application methods of the technique in water flooding and oil production.