The Plugging Research Of Ahead Protective Fluid For Cement Slurry In The Tarim Oilfield

Lost circulation is one of most complex situation which can harm the safety of drilling operation. It will not only kill the time of well drilling, but also may cause a series of complications such as fluid loss, sticking, blowout, well collapse and even borehole scrapped, leading to heavy economic losses.The Kuche Formation of Tarim Depression is characterized by complex lithology,tectonics fracture and petroleum geological condition and small sedimentary coverage.In the process of drilling the well leak case occurred frequently Especially in high water cut in strata, pore formations and fractured formation.Plugging technology in the conventional effect is not good, in formation water erosion function, plugging agent cannot effectively stay, plugging efficiency is lower.For the study of plugging experiment,a simple and novel plugging device for dynamic water washing condition is developed, it can simulate the performance of the plugging fronting liquid in the dynamic water washing condition well, and can simulate all kinds of assessment test,apply on estimating all kinds plugging additives,so that we can preference the best formula of plugging on many various of situation. It is used for lost circulation tests for plugging fronting liquid.The data show that the device has good data repeatability and reliability.The device provides an effective means for the selecting of plugging fronting liquid and the construction plan of plugging, and it has good value for practical use.According to the experimental results and analysis.Research a kind of new ahead protective fluid for cement slurry,which priorring to the plugging slurry into the underground,firstly into the thief zone crack or throats,At a certain time and temperature forms a gel structure strong pace layer.Separating the slurry and the water in the thief zone,ensure that slurry can be effective to filling and solidification, so as to improve the successful rate of plugging in the thief zone. For the ahead protective fluid for cement slurry provides a new train of thought and method, to improve the success rate of complex formation plugging have a major engineering significance.