Preparation Of Light-colored Asphalt Emulsion As Shale Inhibitor

In order to solve the problems of high colloid content,poor emulsion stability,environmental pollution,poor dispersibility,weak plugging and inhibition of asphalt shale inhibitor used in drilling fluid,a new type of light-color asphalt emulsion(LCAE)was prepared in this paper.First of all,there are two kinds of petroleum resins and four kinds of aromatic oils used as the main blending raw materials.Results showed that aromatic oil with high viscosity and petroleum resin with high softening point could prepare a light-colored asphalt by the optimal synthetic condition,which could meet the specification of 70#asphalt standard.After that,there are two kinds of emulsifiers with excellently emulsifying performance that can prepare light-colored asphalt emulsion(LCAE).The emulsifying formula and synthetic conditions of LCAE were optimized by single factor experiments.Under the optimal synthetic conditions,the five-day storage stability of LCAE could reach 1.36%,and the average particle size of the emulsion is 5.08?m.For improving the performance of LCAE in drilling fluid,the modified light-colored asphalt emulsion(MLCAE)was prepared by adding SBS emulsion or SBR emulsion.The experimental results showed that it had better storage stability and the elastic recovery of MLCAE evaporation residue modified by SBR emulsion than that modified by SBS emulsion.When the addition of SBR emulsion was greater than 5wt.%,the softening point of MLCAE evaporation residue tended to be steady.At the last,the LCAE and MLCAE were added to several commonly used water-based drilling fluids for the evaluation of their performance.The experimental results showed that they not only have good compatibility with polymer drilling and potassium-calcium based drilling fluids,but also have little effect on the rheological properties of drilling fluids under the condition of less than 120?.The LCAE and MLCAE could improve the performance of reducing filtration loss and inhibiting shale expansion,and meet the requirements of shale inhibitors in the middle and upper strata of oil and gas drilling.When the addition of LCAE and MLCAE in drilling fluid was 2wt.%,there were optimum performance of drilling fluid and the relative reduction rate of shale expansion of LCAE is 52.84%,the relative reduction rate of shale expansion of MLCAE is 57.88%.The experimental results indicated that the practical application performance of high polymer modified MLCAE in drilling fluid is better.