Western Mountain Front High Pressure Brine Layer Managed Pressure Drilling Process Research

With the continuous maturity of Managed Pressure Drilling technology and the complexity of drilling conditions,MPD technology is more widely used.In my country,it is widely distributed with a salt cream,and the giant saline cream is often developed into a high-pressure saline layer under the influence of deposition structure.For high-pressure saline,conventional treatment measures are to optimize drilling fluid systems and controlled drainage(plug-in and unloading pressure),but there is a disadvantage to varying degrees.This article uses Managed Pressure Drilling techniques to solve the complex problems of underground brought by high pressure saline.Herschel-BuckleyIn order to make the hydraulic calculation more accurate,firstly,the rheological performance experiment of high-temperature and high-pressure oil-based drilling fluid is carried out,the rheological model is optimized as Herschel-Buckley model by linear regression method,and the empirical formulas of the performance parameters of Herschel-Buckley model about temperature and pressure are established;According to the experimental results,the previous wellbore annulus pressure model is modified;According to the different formation conditions of high-pressure brine layer,two process measures of micro leakage and micro overflow are formulated.Therefore,the wellbore pressure models of micro leakage and micro overflow are established,and the parameters of the two models are analyzed;Finally,according to the established model,the process scheme and scheme selection method are determined.High-pressure saline layer fine control drilling technology is mainly used in front of the Kuche Mountain.The depth X well has high pressure saline layers.The pressure coefficient of high-pressure brine layer is less than the bottom,the wall is stable,the density window is large and the malignant loss is not easy.Micro-lost control drilling measures.In the well section,6685～6745m is used for Micro-loss,the loss of the slope is less than 1 m~3/h,and the successful feeding is 60m,and the high-pressure brine layer Micro-loss is successfully drilled.