Preprint Article Version 1 This version is not peer-reviewed

Equivalent Circulation Density Analysis of Geothermal Well by Coupling Temperature

Version 1 : Received: 26 January 2017 / Approved: 27 January 2017 / Online: 27 January 2017 (03:10:16 CET)

A peer-reviewed article of this Preprint also exists.

Zheng, X.; Duan, C.; Yan, Z.; Ye, H.; Wang, Z.; Xia, B. Equivalent Circulation Density Analysis of Geothermal Well by Coupling Temperature. Energies 2017, 10, 268. Zheng, X.; Duan, C.; Yan, Z.; Ye, H.; Wang, Z.; Xia, B. Equivalent Circulation Density Analysis of Geothermal Well by Coupling Temperature. Energies 2017, 10, 268.

Journal reference: Energies 2017, 10, 268
DOI: 10.3390/en10030268

Abstract

The accurate wellbore pressure control not only prevents from lost circulation/blowout and fracturing formation by managing density of drilling fluid, but also improves productivity by mitigating reservoir damage. The geothermal pressure calculated by constant parameters for geothermal well would bring big error easily, as the changes of physical, rheological and thermal properties of drilling fluids with temperature were neglected. This paper researches the wellbore pressure coupling by calculating the temperature distribution with existed model, fitting the rule of density of drilling fluid with temperature and establishing mathematical models to stimulate the wellbore pressures, which is expressed as the variation of Equivalent Circulating Density (ECD) under different conditions. With this method, temperature and ECDs in the wellbore of the first medium-deep geothermal well ZK212 Yangyi Geothermal Field in Tibet were determined, and the sensitivity analysis was simulated by assumed parameters, i.e. circulating time, flow rate, geothermal gradient, diameters of wellbore, rheological models and regimes, the results indicated the geothermal gradient and flow rate were the most influence parameters on the temperature and ECD distribution, and additives added in drilling fluid should be careful which would change the properties of drilling fluid and induce the temperature redistribution. To make sure the safe drilling, velocity of pipes tripping into the hole, depth and diameter of wellbore are considered to control the surge pressure.

Subject Areas

wellbore pressure analysis; equivalent circulating density; geothermal well; wellbore temperature distribution; mathematical modeling

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