Abstract: A model for expressing the change of backscattering flux of foam drilling fluid with time was established, according to the optics property of foam drilling fluid. Furthermore the concept of specific surface area of foam was presented to describe the stability of foam. The mathematical model was established to correlate the specific surface area of foam with time utilizing light backscattering theory and backscattering model. The stabilities of three samples of foam drilling fluid with different density were evaluated by employing infrared scanning turbiscan. The stability of foam drilling fluid was analyzed. The parameters of the backscattering flux ratio model were acquired by data regression. The comparison result of decay rate and half-life verified the correctness and feasibility of the optics evaluating method.

Key words: foam drilling fluid, stability, backscattered light, specific surface area, infrared scanning

摘要： 根据泡沫钻井液的光学性质,建立了后向散射光强度随时间变化的关系模型,并进一步提出了泡沫比表面积的概念.利用光散射原理和后向散射光强度模型,推导出了描述泡沫稳定性的比表面积数学模型.在此基础上,借助红外扫描动态稳定测试仪,分别评价了3种密度的泡沫钻井液的稳定性能,分析了泡沫钻井液的稳定性规律,并进行了回归分析,得到了泡沫钻井液后向散射光强比的模型参数.利用泡沫衰变速度与宏观出液半衰期对比分析结果,验证了光学评价方法的正确性和可行性.

关键词: 泡沫钻井液, 稳定性, 后向散射光, 比表面积, 红外扫描