钻井液转化为水泥浆技术的研究

A RESEARCH ON THE TECHNIQUE OF TRANSFORMING DRILLING FLUID INTO CEMENTING SLURRY

钻井液转化为水泥浆技术，是在钻井液中添加某些胶凝材料和外加剂将其转变成水泥浆直接用作固井材料的新型固井方法。在钻井过程中钻井液承担着冷却润滑钻头，携带岩屑，平衡地层压力，稳定井壁的任务。如果在完成钻井后将钻井液通过一定的方法转化为可固结的材料———固井液，就能达到封隔地层、支撑套管、防止层间流体窜通的目的，这种技术又称为ＭＴＣ（ＭｕｄｔｏＣｅｍｅｎｔ）技术。文中从油气井开发提高效率、降低费用的技术要求出发，论述了采用ＭＴＣ技术是一条可行的路子。实验研究得出用油井水泥，粒化高炉矿渣共同作为胶凝材料，优选合适的分散剂和促凝剂，提出了普通钻井液和聚丙烯酰胺低固相钻井液转化为水泥浆体系的优化配方。这种兼有钻井液和固井液作用的技术，能避免钻井液和水泥浆混合时发生的絮凝现象，提高环空顶替效率，降低废钻井液处理费用，减少固井材料，因而在提高固井质量和降低成本上有很大的潜力。

The technique of transforming drilling fluid into cement slurry is a new cementing method which through adding in some gelling materials and additives, the drilling fluid can be transformed into cement slurry direcfly used as a cementing material. In drilling,the drilling fluid undertakes cooling and lubricating bit,taking up cuttings,balancing formation pressure and stabilizing borehole wall.After well completion,if the drilling fluid can be transformed into a consolidating material—well cementing fluid, the goal of plugging formation,sustaining casing and preventing the interzonal fluids from channeling may be achieved. Such a method is also called MTC(mud to cement) technique. In order to raise the production efficiency and reduce the cost of oil and gas wells, adopting the MTC technique is a feasible way. Through experiment ,it is thought that by taking both oil well cement and granulated blast furnace slag as the gelling materials and optimizing suitable dispersant and accelerant,an optimum formulation of transforming the conventional drilling fluid and polyarylamide low solid mud into a cement slurry system may be obtained. Such a technique which has the function of both drilling fluid and cement slurry can prevent the flocculating effect from being formed when the drilling fluid is mixed with the slurry,raise the displacement efficiency in annular space,reduce the cost of treating waste drilling fluid and decrease the consumption of cementing materials,thus having great potentialities in improving cement job quality and reducing cost,being able to give a reference to production units.