水基微泡沫钻井液防漏堵漏原理研究

EXPERIMENTAL RESEARCH OF THE LEAK RESISTANCE AND LOSS CIRCULATION CONTR OL OF WATER-BASE MICROFOAM DRILLING FLUID

依据低密度和气泡变形堵塞理论,分析了微泡沫钻井液的防漏堵漏原理.采用砂石充填的模拟漏层实验方法,研究了无粘土相微泡沫钻井液防漏堵漏作用效果,结果表明,微泡沫钻井液对80～120目砂石构成的孔隙通道具有最好的堵漏效果,对40～80目砂石构成的孔隙通道具有良好堵漏效果,对10～40目砂石构成的孔隙通道具有一定的堵漏效果,而且,随着压力增加,微泡沫钻井液仍具有堵漏承压能力.

The principles of the leak resistance and los s circulation control of water-base microfoam drilling fluid are analyzed in th e paper according to the low-density and bubble deformation plugging theory. Th rough researching the effects of clay free microfoam drilling fluid on the leak resistance and loss circulation control by use of the analog leakage formation b eing filled up with different sizes of sand grains in the experiment, it was in dicated that the plugging effect of the mirofoam drilling fluid on the pore pass ages made up by the sand grains of 80-120 meshes is best, then the 40-80 meshes , and then the under 40 meshes. Moreover, along with the increase in pressure , the microfoam drilling fluid can still possess the plugging and loading capac ity.