固井液与多功能钻井液泥饼整体固化胶结的可行性探讨

Feasibility of integrated solidification and cementation of cementing fluid with mud cake from multifunctional drilling fluid

研究了MTC固井液和油井水泥浆固井液与多功能钻井液泥饼的胶结状况。试验结果表明,多功能钻井液泥饼的固化反应直接受到固井液水化反应机理和过程的控制。在MTC浆水化反应初期会产生大量发生水化反应必需的可溶性离子,这些可溶性离子渗透到多功能钻井液泥饼内部,为其提供了可激发水化反应的可溶性离子,从而实现了整体固化胶结;而在油井水泥浆与多功能钻井液泥饼的胶结试验中,能够渗透到泥饼内部的大多是Ca2+,而Ca2+离子极易和泥饼中的膨润土颗粒和处理剂发生絮凝反应,形成不会固化而且破坏胶结强度的絮凝产物,剩下的少量Ca(OH)2难以激活多功能钻井液泥饼的水化反应,因此整体固化胶结难以实现。要实现油井水泥浆固化体与多功能钻井液泥饼的整体固化胶结,应该对固井液体系进行必要的改进,使其在水化反应过程中产生的水溶性离子的种类和数量能够满足泥饼固化的需要;同时应该注意研究新的能够激发和促进泥饼固化水化反应的钻井液添加剂,对钻井液进行必要的改进。

The cementation of MTC cementing fluid and oil well cement slurry with the mud cake of multifunctional drilling fluid is studied. Testing results show that the solidification of mud cake from the multifunctional drilling fluid is directly controlled by the hydrating mechanism and process of cementing fluid. During the initial period of MTC slurry hydrating, large amount of soluble ions necessary for hydration are produced and then enter into the mud cake, providing the soluble ions for activating hydrating reaction and realizing the integrated solidification and cementation. While for the case of cementation with oil well cement slurry, ions that enter into the mud cake are mostly Ca2+ , while flocculation is likely to happen between Ca2+ ions and bentonite grains in mud cake and additives, forming flocculate which is free of solidification and negatively impact the cementation strength; it is difficult for the small amount of Ca(OH)2 ions to activate the hydration, thus makes the integrated cementation impossible. To practise the integrated cementation and solidification, necessary modification to cementing fluid system should be carried out, to produce soluble ions of sufficient variety and quantity; at the same time, necessary modification to drilling fluid should also be conducted, by developing new drilling fluid additives that can activate and promote hydration for mud cake solidification.