Investigation And Application Of Polymer Rheological Property

Drilling fluid is known as the"blood"of drilling,and the treating agent is the core component of drilling fluid system,and very few amount will change the performance of drilling fluid to a great extent.It is an important factor to ensure the smooth drilling of drilling fluid in complex stratum.Based on polymer drilling fluid treatment agent as the research object,starting from the natural polymers,synthetic polymer treating agent,based on theoretical research,laboratory experiments and field validation method,combined with internal?molecular weight?and external?concentration,temperature and shear rate?on the rheological properties of polymer were studied,analyzed their rheological characteristics,based on double black water Wells field complex geological conditions of the large bridge,select polymer Vegetable gum plant gum as raw materials,and optimize the drilling fluid formula,to solve the problem such as on-site drilling difficulties,construction progress is slow,It provide reference for that future application of polymer drilling fluid in the phase of leakage and collapse.The main studies and conclusions are as follows:?1?The molecular weight is the internal cause of the change of solution viscosity.The molecular weight of the treating agent can be determined by the viscosity method.Indoor experiment for partially hydrolyzed polyacrylamide,xanthan gum,X-?plant gum,the viscosity of carboxymethyl cellulose was 1.337,1.3164,0.8738 and 1.3374,respectively,using viscosity and molecular weight,the relationship between relative molecular weight of them,which partially hydrolyzed polyacrylamide,X-?xanthan gum,and molecular weight of carboxymethyl cellulose for 1 0⁶,and molecular weight level for X-?plant gum 1 0⁵.?2?Solution concentration?temperature?shear rate and other factors is the viscosity changes of the external cause,through the experiment on the rheological properties of the various treatment analysis,get the viscosity trend along with the change of concentration,temperature,shear rate and rheological model,by using linear regression viscosity change with concentration,temperature,shear rate equation,the analysis and evaluation the effect of the viscosity of polymer treating agent on rheological properties,specific as follows:?1?It was found that that polymer treatment agent of different kind in the same dose condition,the higher the relative molecular weight,the high the solution viscosity;?2?The viscosity of the polymer treating agent increases with the increase of the concentration.When the polymer treatment agent has a higher relative molecular weight,the increase rate of viscosity increases.When the shear rate increases,the increase of viscosity increases,and the concentration has an effect on the viscosity and rheological model of the solution.When the solution concentration is low,the system is characterized by plastic fluid and the rheological property is poor.?3?The viscosity of different kinds of polymer processing agents decreases with the increase of temperature,and the decrease range is different.Moreover,the influence of temperature on solution viscosity is not only single,but also must consider the concentration and other factors at the same time.With the increase of temperature,the degree and number of entanglement between molecules are reduced,so that the extension of the entanglement of the molecular chain is restricted,and the performance of the macroscopic surface is the decrease of viscosity.?4?The viscosity of different kinds of polymer treating agents decreases with the increase of shear rate,and the rate of decrease gradually decreases with the increase of shear rate.The higher the relative molecular weight and concentration of the solution,the more severe the viscosity decreases,and the characteristics of pseudoplastic fluid are displayed.?3?According to the rheological characteristics of drilling fluid,the principle of the combination of large and medium sized molecules was adopted,and the rheological properties of drilling fluid were selected according to the internal factors?molecular weight?and external factors?concentration,temperature and shear rate?,and the optimal formula combination was obtained by orthogonal experiment1LH₂O+0.8%X-?+400ppmX-?+0.4‰NaOH.?4?The optimal formula was tested on the field test of DZ-66-96,DZ-66-098and DZ-66-102G on the black well,and the core adoption rate reached 85⁹0%,and the mechanical drilling speed reached 1.2 m/h,and the efficiency of the platform increased by 1² times,which solved the difficulty of drilling and sampling in the double line of the black water well,which could provide reference for the application of similar leakage and collapse formation drilling.