Study On High Temperature W/o Drilling Fluid And Its Rheological Properties

Nowadays,with the continuous development and improvement of drilling technology,the conditions of drilling deep wells,ultra-deep wells greatly increased.With the increase of drilling depth,the temperature and pressure in the well are also higher.The increase of temperature will decrease the apparent viscosity and shear stress of the drilling fluid,and the increase of pressure will increase the apparent viscosity and shear stress.Oil-based drilling fluid has a strong inhibitory,and it is conducive to the stability of the well wall;good lubrication,and it is conducive to improving the characteristics of mechanical drilling velocity,while it has good temperature resistance.Therefore,oil-based drilling fluid have more advantages in drilling complex wells such as high-temperature deep wells and horizontal wells.At present,oil-based drilling fluid have become an important measure to solve the drilling problem of complex formation.However,in the case of high temperature and high pressure,the performance of oil-based drilling fluid will change dramatically and should not be controlled and adjusted.Rheology is one of the important properties of drilling fluid,it refers to the drilling fluid flow and deformation characteristics in the external force.How to more effectively control the temperature and pressure on the rheological performance is the main task of the moment,it is the key to solve the resistance of high temperature and high pressure oil-based drilling fluid.On the basis of full investigation,firstly,the emulsifier of the anti-high temperature water-in-oil drilling fluid was studied.The anti-temperature principle of the water-in-oil drilling fluid was analyzed,and the molecular structure of the emulsifier was designed.The Gemini-type ammonium salt-type surfactant was synthesized and the emulsifying performance was evaluated.Secondly,through the deep analysis of the basic components and the regulation mechanism of the water-in-oil drilling fluid,the basic formula of the anti-high temperature water-in-oil drilling fluid is finally selected.At the same time,the research on the rheological properties of the drilling fluid is carried out.For this reason,the factors influencing the rheological properties of the drilling fluid are analyzed.The influence of the temperature and pressure on the rheological properties of the drilling fluid is studied.The viscosity of the drilling fluid sample is described mathematically with the Herschel-Bulkley.To provide the basis for the selection and design of anti-high temperature water-in-oil drilling fluid system;to improve the high temperature and deep well exploration and development benefits to provide technical support.The research results have laid a solid theoretical foundation for further field testing of water-in-oil drilling fluid technology in China,and have important practical application value.