The Effect Of Mud Cake Performance On Washing Efficiency

With the growing demand for oil and gas resources, and the increase of exploration degree, low permeability reservoir is the main object of the development of the current and future oil and gas exploration. Horizontal well drilling technology and reservoir overall transformation technology is one of the main technical means of the development of low permeability reservoirs, if the mud cake has not been cleaned in the process of drilling horizontal Wells, would increase cement annulus and formation easy tear, causing the oil and gas channeling, which affect the cementing quality. So to improve the cementing quality, the low permeability reservoir mud cake washing efficiency appears increasingly important. This paper mainly study the influence of the performance of the filter cake washing efficiency, aims to put forward a kind of drilling fluid additives through quantitative changing performance and then the method to improve the cementing quality of mud cake.This paper is aimed at the existing under high temperature and high pressure mud cake formation and flushing device was improved, the deficiency of the and mud cake performance tuning method is put forward, and improve irrigation construction technology improve the efficiency of filter cake washing. Concrete of the main research work and the main achievements are as follows:(1) on the basis of researching at home and abroad about the filter cake mud formation and washing device, based on the cementing annulus wall and evaluation are compared.in surface shear rate at equal principle and combined with drilling fluid and flushing fluid rheological model, to improve the existing dynamic mud cake formation and high temperature and high pressure washing device, the device simulated flushing fluid flow and drilling fluid rinses the size of the annular return velocity one-to-one correspondence, which would be quantitatively simulate the forming of mud cake and flushing.(2) Using the shear stress model of mud cake, analyzing the main performance parameters of influencing the filter cake washing efficiency, evaluating by indoor experiment of mud cake washing efficiency, and the strength of the filter cake was obtained by grey correlation theory analysis on the flushing efficiency had the greatest influence, followed by the compressibility, again is the thickness of mud cake, finally, the permeability of filter cake.(3) Through the analysis of the effect of drilling fluid additives on the properties of mud cake, different drilling fluid systems, need to adjust the different additives and their added amount, in order to improve the performance of the filter cake, improve the efficiency of washing. Such as 1# drilling fluid at the same time, add 1% CMC and 0.7% organic dispersant can reduce the intensity of mud cake, effectively improve the mud cake washing efficiency, irrigation efficiency to more than 75%.And 2# drilling fluid loss of water volume is 1%～1.5%, the diluent added amount was 0.7%, the amount of potassium chloride with 0.3% can reduce the mud cake strength and the compression coefficient, make the washing efficiency has improved considerably.(4) By adjusting drilling additives of fluid to improve the performance of mud cake, optimizing annular return velocity, optimizing drilling flushing fluid system and dosage, Which could improve the washing efficiency that mud cake of horizontal Wells in low permeability reservoirs.