Application Study On Improving The Performance Of Drilling Fluid By Nanoparticles In Shenbei Oil Field

Low grade reservoir and buried hill reservoir of deep Es4 in Liaohe Oilfield have become the focus of exploration and development,and also an important guarantee for resource replacement in the future.The fourth member of Shahejie Formation in Shenbei block is buried deep,with an average burial depth of 2700-4200m.The mudstone in the large section of the formation collapses seriously periodically,so the conventional KCl drilling fluid can not meet the safety requirements of long-term wellbore.In order to improve the safety of drilling operation and increase the production,this study intends to improve the drilling fluid formula of conventional KCl system,adding nano particles to improve the filtration performance of drilling fluid.Through literature research,it is found that adding nano particles into drilling fluid can change the filtration performance and rock carrying capacity of drilling fluid.Based on this,the main research direction of this paper is put forward,that is,adding titanium dioxide and silica nanoparticles into drilling fluid for drilling fluid modification,and analyzing the performance improvement after modification.The mechanism of improving the performance of drilling fluid after the ratio of nano particles to conventional drilling fluid is analyzed,and a 1:1 ratio of titanium dioxide and silica nanoparticles is proposed for follow-up study.The results show that the addition of nano particles can optimize the rheological and filtration properties of drilling fluid,improve the temperature resistance and prolong the life of drilling fluid.By using the method of simulation analysis,the rock carrying efficiency of drilling fluid with nano particles is established and calculated,and the calculation results are analyzed.The comparison with the test results shows that the new drilling fluid formula can effectively improve the rock carrying efficiency of drilling fluid.The application of modified drilling fluid formula in Shenbei block of Liaohe Oilfield is studied in this paper.Field tests are carried out in 8 wells with the same opening interval of2700m-4200m after optimization.Compared with the three wells before optimization,the average reaming time of the same layer is reduced from 163 hours to 74 hours,with a decrease rate of 54.60%;the drilling cuttings treatment capacity is increased from 2.36m³·100m^-1 to3.43m3·100m^-1 The average single well sticking time decreased from 1.67 times to 0.125 times,which decreased by 92.5%.By comparing the sticking times and other parameters,it is confirmed that the modified drilling fluid has good application effect.