基于线性回归的油基钻井液有害低密度固相含量计算方法

Calculation of Harmful Low Density Solids Content in Oil Base Drilling Fluids Using Linear Regression Method

随着页岩气大规模开发,高密度油基钻井液应用越来越广泛。在钻井过程中,小颗粒钻屑将不断进入油基钻井液中,极大地影响了钻井液的性能,目前的研究缺乏计算油基钻井液中钻屑含量的方法。在GB/T 16783.2《石油天然气工业钻井液现场测试第2部分:油基钻井液》中只规定了低密度固相含量的计算方法,并未对有用低密度固相和有害低密度固相进行有效区分。通过对比井浆和室内新配浆的固相含量,利用线性回归得出了一种有害低密度固相含量计算方法,并以现场钻井液为例进行校核,通过线性回归的方法,计算得到的固相含量与实测固相含量相差较小,误差小于3%,可以更精确地计算出有害固相含量,给油基钻井液的性能维护提供了重要的标准。该方法计算简便、误差小,具有较高的现场应用价值。

With the large scale development of shale gas,high density oil base drilling fluids are finding wide application in shale gas drilling.During drilling,small particles are continuously entering into the drilling fluid,greatly affecting the performance of the drilling fluid.Presently there is no method for calculating the drilled cutting content of oil base drilling fluids.The standard GB/T 16783.2 only gives a method of calculating the content of low density solids,which is unable to differentiate the wanted low density solids and the unwanted harmful low density solids.By comparing the solids contents of drilling fluid taken from a well and the mud freshly made in laboratory,a method for calculating the content of harmful low density solids was developed through linear regression.This method was also checked for its accuracy using muds taken from fields.Errors between the solids content obtained from linear regression and the solids content actually measured were less than 3%,indicating that this method can be used to accurately calculate the content of harmful solids.This simple method has provided an important standard on which the properties of oil base drilling fluids can be maintained.Small calculation errors make the method valuable and feasible to field application.