Study On The Effects Of Ultraflne Particles In Drilling Fluid Performance

Drilling for oil and gas development in China is gradually to the deeper and wider areas.Because of deep well and ultra-deep well in the reservoir is deep, the formation pressurechange is big, complex lithology, they are liable to occur pipe sticking, lost circulation andblowout even collapse accident during the drilling process. As a result, higher performancerequirement for drilling fluid is put forward.In this paper,the Mg（OH）₂ultrafine particles were obtained by reaction betweenMgCl₂·6H₂O and NaOH; and Al₂O₃ultrafine particles were obtained by reaction betweenAl₂（SO4）₃·18H₂O and （NH₄）₂CO₃; and ZrO2ultrafine particles were obtained by reactionbetween NaBO2and ZrOCl₂; Several products were prepared into drilling fluid, respectively,And their Rheological properties were tested together; The relationship between the grain sizeparameters of ultrafine particles and drilling fluid properties change was analyzed by theSPSS analysis software. Reaction mechanism was analyzed, the grading scheme was obtainedthrough optimization design.formula of ultrafine particles of different particle size in drillingfluid was obtained.Study found that,the ultrafine particles can improve AV, YP, G1′, G10′and mud cakethickness of drilling fluid. SPSS study found that0.2%ultrafine particles added amount, theinitial gel strength variation in drilling fluid and Al₂O₃ultrafine particles diameter D50area isa equation of goodness of fit preferably; the initial gel strength variation and final gel strengthvariation are proportional to D50area diameter and Length diameter of Mg（OH）₂ultrafineparticles in drilling fluid, the equation of goodness of fit better。...