Experimental Study On Improving Technical Quality Of Cementing In Horizontal Wells In Western

Technology of horizontal well is the important way for enhancing reserve and productivity in the region of western Sichuan. However, there are a number of problems which restricts cementing quality of horizontal well, for instance, geological conditions, stratum instability, munch solid content in drilling fluid, thickness mud cake and insufficiency circulation at earlier stage et al. Fibrous washing fluid and casing swirl centralizer were put forward to solving problems, and laboratory simulating test was use to study effective of removing cutting bed and mud cake in this paper.The effectiveness evaluation of dynamic mud cake washing shows that:washing efficiency of mud cake increases with concentration of fiber and washing speed increase. A simulator of displacement efficiency was taken to study concentration of the influence of fiber, displacement, eccentricity and viscosity on rock debris. It was found that the washing efficiency of cutting bed is proportion to annular displacement, and is inversely proportional to the eccentricity of casing, and is proportion to viscosity of flushing fluid. The best concentration of fiber was confirmed by above experimental.A simulator of displacement efficiency was taken to analysis various displacement and eccentricity, the effective of cleaning rock of swirl centralizer and conventional centralizer. It was found that efficiency of swirl centralizer is obviously higher than conventional centralizer at the same experiment condition, if the experimental condition never changed. And the efficiency of rock debris inversely proportion to distance of swirl centralizer from rock debris.Annular without swirl flow field and swirl flow field were analyzed flow with PIV. It was found that the distribution of axial velocity for narrow gap of annular at horizontal well is similarity to swirl flow, and the high velocity is at middle region for narrow gap, and the small velocity is nearby casings and borehole walls, and the most small is at borehole walls. This velocity of swirl flow field is smaller than without swirl flow field. This velocity of irrotational flow field is symmetry to center line of annular gap. However, for swirl flow field, its peak point is deviation to borehole walls and tangential-velocity component is attenuation along axial direction.Taking XinSha X well as example, the flushing fluid and the interval of swirl centralizer for this well are designed and optimized.