The Development Of Micro-foam Drlling Fluid And The Study Of Its Properties

Recently both domestic and overseas drilling fluid fields advanced a new kind of low density system which is called tri-phase recyclable micro-foam drilling fluid. It can overcome most disadvantages of conventional foam system, such as pumping and one-off use that may lead to a lot of waste of agents and serious environmental pollution because of discharge. The study is under the condition of the low shearing rate.In this study, a new foaming agent is confected, and this kind of foaming agent has the advantage of high expansion rate, fine foam, long life and good resistant ability to salt, calcium and oil pollution. A new stabilizing agent is also synthesized in this study, and the effect of the stabilizing agent is very well. On the base of new foaming agent and stabilizing agent, a micro-foam drilling fluid system is developed for meeting the need of drilling. The micro-foam is produced the physical churning method. This drilling fluid has the performance of fine foam, low density, long life and good fluidity, and its ability of temperature resistance, salt resistance, calcium resistance and oil pollution resistance is also nice. When the shearing rate of the drilling fluid change, the performances change accordingly. The shearing rate is bigger, the system is more stable and the performance of the system is better. However, when the shaearing rate reaches 1600rpm, the results tend to stable.When the drilling fluid is in an alkalescent environment, in another word, the range of its pH value is 8-10, the drilling fluid will be in the more stable state. When the the temperature of the drilling fluid change, the performances change accordingly. By the experiment of leak-off, we achieve the leak-off mechanism, and confirm that the drilling fluid has a good performance of leak-off in the low-pressure formation. The micro-foam system is tiny, spherical, symmetrical, disaccumulative, and disconsecutive. The system has many advantages such as better stability, adjustable density, low filtrate.