A Coupled Model of Two-Phase Fluid Flow and Heat Transfer to Transient Temperature Distribution and Seepage Characteristics for Water-Flooding Production Well with Multiple Pay Zones

Abstract

Temperature is one of the most prominent factors affecting production operations, predicting the accurate wellbore-formation temperature in a water-flooding production well is of great importance for multiple applications. In this paper, an improved coupled model of oil–water two-phase fluid flow and heat transfer was developed to investigate the transient temperature behavior for a producing well with multiple pay zones. Firstly, a novel method was derived to simulate the water saturation and the water breakthrough time (WBT) for tubing, which are key monitoring parameters in the process of water flooding. Then, we incorporated water saturation and an equation set for immiscible displacement to calculate the seepage velocity and the pressure of the two-phase fluid in the pay zones. Next, the upward seepage velocity of the tubing fluid change with depth was focused on, and the proper coupled initial and boundary conditions are presented at the interfaces, therewith the implicit finite difference method was used to compute the transient temperature with the input of the seepage characteristics for the reservoirs. Meanwhile, the validity of the proposed model has been verified by the typical model. Finally, a sensitivity analysis delineated that the production rate and the production time had a significant impact on the tubing fluid temperature. The overburden was hotter with a lower volumetric heat capacity or a higher thermal conductivity. In addition, the sensitivity of the porosity and the irreducible water saturation to formation temperature was significantly different before and after the WBT. The coupled model presented herein helps to advance the transient seepage characteristics analysis of pay zones, the precise temperature prediction is very useful for reservoir characterization and production analysis purposes and provides insight for designing the exploitation scheme in deep reservoirs and geothermal resources.

Optimized geothermal energy extraction from hot dry rocks using a horizontal well with different exploitation schemes

“…Conduction and convection dominated the heat transfers of the working fluids in the vertical pipes (including the TIP V and ANN V ) during the exploitation. In addition, in the vertical pipes of the wellbore, the vertical component of the working fluid's downward/ upward seepage velocity was highly valued, and the radial component can be neglected (Huang et al 2019;Xu 2020;Zhang et al 2021). Thus, the heat transfer equation inside the vertical pipes can be written as follows:…”

“…Heat conduction and convection dominated the heat transfer of the working fluids in the horizontal conduits (including the TIP H and ANN H ). Thus, the temperature field equation can be expressed as follows (Huang et al 2019;Wang 2019;Zhang et al 2021):…”

“…For the HDR and impermeable medium (pipes/cements), heat conduction dominates the heat transfer rather than convection. Thus, their transient temperature field governing equation can be given by the following (Fang 2018;Huang et al 2019):…”

Prediction of Dynamic Temperature and Thermal Front in a Multi-Aquifer Thermal Energy Storage System with Reinjection

“…In addition, in this fully coupled thermal-hydraulic model, the major assumptions and approximations are as follows [8,40,41]:…”

“…However, it is crucial to determine the long-term performance of ATES systems before reinjection. Simulation technology of fluid flow and heat transfer processes has been integral to scientific research and applications over the past decades [8]. Despite the many efforts made to develop accurate numerical Energies 2023, 16, 7358 2 of 24 models, even with many simulations of geothermal systems being widely applied in over 100 fields worldwide [6], the complex nature of this issue still motivates several studies [9].…”