Study On Regulating Control Technology Of Weighing Agent Of Rheological Properties Of Ultra-high Density Drilling Fluid

Since the industrial revolution,coal and oil have been the driving force for the world to move forward.The development of various countries has also increasingly dependent on oil energy.In recent years,with the increasing demand for oil and gas resources in china,the exploration and development of oil and gas resources in deep and complex formations have gradually become the focus.As we all know,the sloughing hole,lost circulation,and other dangerous accidents often occurred in deep and ultra-deep well due to high formation pressure,high temperature and complexly geological conditions.Therefore,it has a higher requirement for ultra-high density drilling fluid.In fact,the ultra-high density drilling fluid rheological control technology has always been the key technology research of drilling fluid,which is still facing serious challenges in the continuous development.In this paper,the rheological control problems prevalent in ultra-high density drilling fluids are systematically analyzed.And the research on experiment is studied around the weighting agent which is the greatest impact on rheological property.The selection and treatment of new weighting materials can improve the rheological properties of drilling fluid to some extent.The main research contents and results are as follows:First of all,the basic formula optimization experiment was carried out.The influence of the amount of bentonite on the key performance of ultra-high density drilling fluid was studied by the selection of matching treatment agent and the amount of bentonite.It is found that when the amount of bentonite is more than 2%,the viscosity and shearing force of the drilling fluid are greatly increased.Finally,the optimum amount of bentonite in the ultra-high density drilling fluid is 1.78% and the amount of the treatment agent is finally determined.Secondly,through compounding weighting agent theory research and systematic experiment,it can be concluded that when compounding weighting agent particle size less than 38 um is 65.3% and 38~120um is 34.7%,the compact powder accumulation effect can be achieved,which contribute to rheological properties and filtration improvement.Finally,the study on surface activation technology scheme of iron ore powder is carried out which is the key weighting agent and is widely used in the ultra-high density drilling fluid.The activator NP-15 was used to activate the iron ore powder.The effects of activation time,activation temperature and the activator dosage on the rheological properties of ultra-high density drilling fluid were studied.At last,the activation conditions of the activated iron ore powder were optimized.When the amount of NP-15 was 2.0%,at 85? for 30 minutes,the rheological property and filtration property of drilling fluid have a better effect.