Study On New Type Water-in-oil Emulsion Drilling Fluid In Daqing Oilfield Source 211 Block

At present,oil-based drilling fluid in the drilling industry in the rapid development,because of its high temperature resistance,salt damage,calcium intrusion,good lubrication,wellbore stability and so on.But because of its costly and serious pollution of the reservoir,limiting its use in drilling work.When the water-based drilling fluid system is used,the complicated problems such as shrinkage,wall peeling,collapse and accumulation of cuttings are easy to affect the exploration and development efficiency.When drilling difficult and complex wells and a variety of special technology wells,only the use of oil-based drilling fluid to meet the practical application of the scene.In China's economic sustainable development,attention to the ecological protection of the big situation,the drilling industry is also more and more attention to the protection of the reservoir,oil-based drilling fluid in the environmental protection requirements more stringent,the existing oil-based drilling fluid has been unable to meet the current drilling needs,which requires the development of a set of both to meet the drilling needs and can protect the reservoir of new oil-based drilling fluid system.In this paper,a new type of water-in-oil emulsified drilling fluid system was developed.First of all,through the comprehensive comparison of the properties and sources of several oils,it is necessary to determine the biodegradable biodiesel as the base oil of the new water-in-oil emulsified drilling fluid system.And then through the gelation test,high temperature aging test and high temperature and high pressure filtration test and other methods,excellent emulsification performance and good pollution of the emulsifier,good gelatinity and a certain mention of the ability to mention the cutting of high-performance organic soil and high temperature and pressure Filtration loss of less than 5ml of the compound type filter loss agent.And then the drilling fluid system for drilling performance evaluation,and optimize the treatment agent in the system of the optimal amount.The final formula for the determination of the new water-in-oil emulsified drilling fluid system is: base liquid(biodiesel)+ main emulsifier 3% + auxiliary emulsifier 1% + organic soil 2% + fluid loss 3.5% + 20% CaCl2 solution Volume 20%)+ 3% 1250 mesh CaCO3.The new type of water-in-oil emulsified drilling fluid was determined by the method of drilling fluid rheology experiment,electrical stability experiment,temperature resistance test,lubrication performance experiment,anti-pollution performance experiment,suppression performanceevaluation experiment and reservoir protection performance evaluation experiment Strong,anti-120 ? high temperature,good lubricity,anti-15% of the calcium salt and water pollution capacity,cuttings recovery rate of 98% or more to inhibit the shale hydration and dispersibility and permeability recovery value of 97% or more Reservoir protection.The research system satisfies the requirements of environmental protection and economic demand in complex formation drilling wells such as high temperature deep wells and salt paste layers.It has greatly improved the oil-based drilling fluid in Daqing,and through the application of two wells in the field,Drilling fluid rheology,temperature resistance,filter loss,etc.can meet the drilling needs.For our country to carry out a deeper layer of environmental protection oil-based drilling fluid technology development has laid a theoretical and practical basis.