Prediction of drilling cycle temperature of deep wells in Longdong area
In the Longdong area of the Changqing Oilfield,the depths of certain natural gas wells are around 5000 meters,and the corresponding formation temperature exceeds 130 ℃.However,with the continuous development of deep oil and gas,unconventional oil and gas resources,and shale gas in this region,high temperature has become a significant constraint on drilling operations.To prevent potential engineering accidents caused by high temperatures underground,this paper establishes a two-dimensional drilling circulation temperature prediction model,conducts an analysis of wellbore temperature characteristics,and provides theoretical support for the selection of drilling fluids and drilling tools.The research findings indicate:1)Initially after the start of pump circulation,the wellhead temperature rises rapidly,while the bottomhole temperature drops rapidly,and within the subsequent 1.5 hours,the temperature changes at both ends gradually slow down.2)At the same well depth,as the circulation time increases,the temperatures of the drilling fluid inside the drill string and inside the annulus gradually decrease,and correspondingly,the temperatures of the drilling fluid in the annulus and inside the drill string at the respective positions also decrease.3)Within the predicted temperature range,experiments were conducted on the apparent viscosity and plastic viscosity of three drilling fluid systems for the well,and the results show that viscosity changes are significantly affected by temperature.4)Within the predicted temperature range,with the ternary ethylene-propylene rubber as the study object,the thickness of the rubber sealing ring gradually decreases,the hardness increases,and the compressive permanent deformation rate increases with the increase in aging time and temperature.The results of this predictive model align with actual production,providing valuable guidance for design and selection,thus holding important significance in the research field.
Longdong areadeep well drillingtemperature predictiondrilling temperature
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