Numerical Simulation Of Ice Auger Drilling Fluid For Environmental Impact In Antarctic

With the rapid development of economic globalization, countries have an increasingdemand for resource; meanwhile they also bring many problems, such as the excessiveexploitation and utilization of resources, environmental pollution and climate change issues. Inorder to solve the common concern questions like human resources, environment and climate soon so forth, more and more countries in the world started to pay much attention to the Antarcticscientific research, in the Antarctic continent build scientific stations and start ice core scientificdrilling work.Safety and environmental protection、good performance of cryogenic fluid is one of the keytechnology of Antarctic ice core drilling, on the basis of thorough analysis the polar used drillingfluid at domestic and abroad, according to the Antarctic ice sheet characteristics andrequirements of drilling fluid at Dome A, carried out a theoretical analysis of ultra-lowtemperature drilling fluid components materials, identified for the Antarctic ice sheet with thetype of drilling fluid, drilling test of fatty acid ester and its mixture viscosity and density underdifferent temperature conditions, the change mechanism of drilling fluid under the condition oflow temperature for a thorough theoretical analysis.Deep Antarctic ice core drilling is an important part of the Antarctic expedition, throughaccess to high quality ice core sample composition, mechanical properties and structure of icedynamic properties in a series of problems, such as in-depth study, at the same time also need toresearch unknown ice and bedrock, and their contact relationship, in order to obtain theinformation of geological structure at the South Pole and resources, to guide the polar scientificresearch work in the future. When engaged in polar drilling, we must use drilling fluid, in orderto better protect the Antarctic environment, we must develop a low pollution of drilling fluidsystem. In careful analysis the Antarctic Dome A specific geographical conditions and thecharacteristics of the drilling strata, on the basis of the drilling fluid in the ice and snow, ice andbedrock under the ice layer of leakage, drilling fluid in the process of using volatilization etc.The Antarctic environment pollution caused by the problems such as system is analyzed, themethod of drilling fluid pollution assessment is determined. Using the Visual Modflow software of the drilling fluid under the ice and ice bedrock layer leakage problem is simulated; A softwarefor the volatilization of drilling fluid for the EIA Pro is used to numerically simulate theinfluence of polar climate, establish the corresponding mathematical model, the researchanalyzed the drilling fluid to the Antarctic rock under air, ice, snow, etc. The influence law ofenvironmental protection to strengthen the South Pole has very important practical and long-termsignificance.Paper based on the drilling site area groundwater system mathematical model is established,based on the drilling sites are natural geography, the analysis of the hydrogeological condition,the layer is regarded as the object of the numerical simulation for the foundation, groundwaterVisual Modflow software is adopted to establish the numerical model of groundwater flow andsolute transport model, the drilling sites are falling snow, migration and diffusion of pollutants inthe bedrock layer numerical simulation of the pollutants in the falling snow forecast in the nextfew years, the concentration and pollution plume in the bedrock layer.(1)snow: Dispersion coefficient is equal to0.1[1/(mg/L)], four years later, the migration ofthe largest concentration C4=70mg/L, the pollution areaS4≈0.4880m2,10years later, themigration of the largest concentration C10=160mg/L, the pollution area S10≈0.6283m2;Dispersion coefficient is equal to0.01[1/(mg/L)], four years later, the migration of the largestconcentration C4=450mg/L, the pollution area S4≈1.4752m2,10years later, the migration of thelargest concentration of C10=700mg/L, the pollution area S10≈3.719m2; Dispersion coefficient isequal to0.001[1/(mg/L)], four years later, the migration of the largest concentrationC4=1200mg/L, the pollution area S4≈9.8779m2,10years later, the migration of the largestconcentrationC10=1200mg/L, the pollution areaS10≈28.3447m2.(2)rock: Dispersion coefficient is equal to0.1[1/(mg/L)], four years later, the migration ofthe largest concentration C4=400mg/L, the pollution areaS4≈0.0150m2,10years later, themigration of the largest concentration C10=1000mg/L, the pollution areaS10≈0.0170m; dispersioncoefficient is equal to0.01[1/(mg/L)], four years later, the migration of the largest concentrationC4=4000mg/L, the pollution areaS4≈0.0150m2,10years later, the migration of the largestconcentration C10=10000mg/L,the pollution areaS10≈0.0170m. As can be seen from the results of the model prediction, Drilling pollutants mainly rely onits own role in the horizontal direction diffusion transport, When diffusion coefficient decreases,The maximum increase in the concentration of contaminant transport, Increased pollution plumearea. Papers low fatty acid ester fluids, And as a contaminant, Analysis of the pollutants overtime the changes in the diffusion transport, Predicted results basically reflect the distribution ofthe entire drilling field solute transport in the region. This analysis and prediction methodssuitable for the study of drilling fluid in the snow layer, bedrock diffusion problems, Also able toassess the environmental impact generated by the drilling fluid to the formation accurately.Use atmospheric EIA ProA professional auxiliary system to establish the atmospheric model,according to the results of atmospheric model, effective protection measures are put forward.First introducing the SCREEN3on the estimate model, setting up the model parameters,simulating and analyzing of the various parameters on the maximum of the rate and the influencelaw of concentration: when the input gas flow rate by25m3/s reduced to10m3/s, pollutantsaccounted for the largest rate by Pmax=27.18％increase to Pmax=284％, maximum concentrationincreased from1.36E-01to1.42E-00; When the gas emission rate from0.17g/s to0.017g/s, therate of pollutants accounted for the largest by Pmax=27.18％%to reduce to Pmax=2.72％,maximum concentration decreased from1.36E-01to1.36E-02; When the gas emissions increasedfrom5m to10m, pollutants accounted for the largest rate by Pmax=27.18%to reduce toPmax=3.9％, maximum concentration decreased from1.36E-01to1.95E-02. To risk prediction,and then used to calculate pollutant emission in different time after area.Can be seen from the atmospheric prediction model, the main parameters affecting theprediction model is gas flow、 gas emission rate and gas emission height, etc. Through theanalysis of pollution meteorology, the characteristics of atmospheric pollution can beenspeculated, but also can provide conforms to the situation in the region for atmospheric diffusionmodel parameters.Research methods and mathematical determined accurately simulate the establishment ofdrilling for ice layer, bedrock, atmospheric diffusion problems, Antarctic ice drilling fluidsprovides a reliable means of assessing the formation of leakage and air pollution, Antarctic icedrilling fluids provides a reliable means of assessing the formation of leakage and air pollution, For the acceleration of Antarctic deep Bing research project has important theoretical andpractical significance. Research results for conventional oil and gas exploration, and other areasof solid mineral exploration, Pollution assessment of the drilling fluid also has importantreference value.