Analysis of Coupled Wellbore Temperature and Pressure Calculation Model and Influence Factors under Multi-Pressure System in Deep-Water Drilling

Abstract

The purpose of this paper is to discuss the variation of wellbore temperature and bottom-hole pressure with key factors in the case of coupled temperature and pressure under multi-pressure system during deep-water drilling circulation. According to the law of energy conservation and momentum equation, the coupled temperature and pressure calculation model under multi-pressure system is developed by using the comprehensive convective heat transfer coefficient. The model is discretized and solved by finite difference method and Gauss Seidel iteration respectively. Then the calculation results of this paper are compared and verified with previous research models and field measured data. The results show that when the multi-pressure system is located in the middle formation, the temperature of the annulus corresponding to location of the system is the most affected, and the temperature of the other areas in annulus is hardly affected. However, when the multi-pressure system is located at the bottom hole, the annulus temperature is greatly affected from bottom hole to mudline. In addition, the thermo-physical parameters of the drilling fluid can be changed by overflow and leakage. When only overflow occurs, the annulus temperature increases the most, but the viscosity decreases the most. When only leakage occurs, the annulus temperature decreases the most and the viscosity increases the most. However, when the overflow rate is greater than the leakage rate, the mud density and bottom-hole pressure increase the most, and both increase the least when only leakage occurs. Meanwhile, bottom-hole pressure increases with the increase of pump rate but decreases with the increase of inlet temperature. The research results can provide theoretical guidance for safe drilling in complex formations such as multi-pressure systems.

Solution and Analysis of Wellbore Temperature and Pressure Field Coupling Model under Lost Circulation

“…With the increase in oil and gas exploration and development, the research frontier of the petroleum industry has gradually shifted to the development of land deep oil and gas reservoirs and deep-water drilling. , Complex geological conditions result in drilling operations facing engineering problems such as abnormally high temperature, high pressure, and narrow safe density window, resulting in frequent downhole complex accidents such as lost circulation. , In addition, borehole temperature is not only an important parameter for wellbore stability analysis and drilling design but also has a significant impact on drilling fluid properties and cementing quality. − Moreover, under the loss condition, the fluid in the annulus is in an unsteady-state flow, and the leaked fluid also reduces the formation temperature near the wellbore and changes the original temperature and pressure distribution in the wellbore, which seriously affect the physical parameters such as drilling fluid density and viscosity, making the loss situation more complex. − Therefore, studying the variation law of wellbore temperature and pressure in the process of lost circulation is of great significance for safe and efficient drilling.…”

Establishment and application of temperature–pressure coupling model for opening and closing wells in HTHP gas wells

“…In 2010, Zhenghe et al (2010) in order to obtain the bottom hole pressure in the shut-in test more accurately, based on Hasan et al (2005) research, considered the fluid phase change and proposed the wellbore unsteady heat transfer model corresponding to the shut-in state of high-temperature and high-pressure gas wells, which can effectively reflect the change of wellbore temperature and pressure after shut-in. Abdelhafiz et al (2021) and Zhang et al (2019) pay special attention to the calculation of gas wells in the sea. Up to now, the prediction model of wellbore temperature and pressure has developed from one-dimensional to multidimensional, and from steady state to unsteady state (Zheng et al, 2020).…”

Assessment of the Effective Variants Leading to Higher Efficiency for the Geothermal Doublet, Using Numerical Analysis‒Case Study from Poland (Szczecin Trough)

“…The numerical models enable us to recognize both the geological structure of rock formations and the processes which operate within them [17][18][19][20][21]. Many interesting aspects of heat transfer and fluid flow in geothermal applications can be found in numerous publications [22][23][24][25][26][27]. There have been many attempts to analyze heterogeneous porous materials especially when it correlates with physical parameters [28,29].…”