Drift-Flux Model for Multi-Segment Wellbore Simulation
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Solution Overview
Problem
Current reservoir simulators, such as ECLIPSE, are inadequate for modeling fluid flow in horizontal and near-horizontal wellbores due to undefined drift-flux models in the -90° to +2° inclination range, leading to inaccurate and time-consuming simulations, especially with friction drops impacting production and water accumulation issues.
Innovation Solution
A gas-liquid drift-flux model is developed to account for pipe inclinations between -90° and +90°, allowing for accurate modeling of horizontal or near-horizontal wellbores by relating drift velocity to mixture velocity, incorporating parameters that correct for phase transitions and mixture velocity thresholds, enabling efficient simulation of fluid flow in all pipe inclinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ECLIPSE simulator with the drift-flux model of Holmes is used for upward fluid flow, then the simulation provides valuable results, but the model is undefined for horizontal, near-horizontal, and downward flow (-90°≤θ≤+2°)
Solution Approach 1:
The drift-flux model is extended to cover the full inclination range from -90° to +90°, making it universally applicable to all wellbore orientations including horizontal, near-horizontal, and downward flows. This is achieved by modifying the model equations to handle all inclination angles, thereby eliminating the need for different models or assumptions for different flow directions.
Solution Approach 2:
The model parameters are adjusted and redefined to accommodate horizontal and downward flows. Specifically, the drift flux equations are modified to account for different gravitational effects at various inclinations, allowing the model to accurately represent fluid behavior across the complete range of wellbore orientations without requiring the homogeneous flow assumption.
2Reliability
If the homogeneous flow (no-slip) assumption is applied for horizontal segments, then the simulator can function, but the computations take much longer to converge and the results are less accurate
Solution Approach 1:
The drift-flux model parameters are specifically optimized for horizontal flow conditions, replacing the need for the homogeneous flow assumption. By using the modified drift-flux equations with appropriate parameter values for horizontal orientations, the model achieves both faster convergence and higher accuracy compared to the traditional no-slip approach.
3Measurement precision
If horizontal wells are drilled with slight undulations creating sumps, then water accumulation occurs impacting simulation accuracy, but the drift-flux model is undefined for these conditions
Solution Approach 1:
The drift-flux model is extended to handle downward and near-horizontal flows where sumps form, enabling accurate simulation of water accumulation in undulating horizontal wells. The model now provides continuous coverage across all inclination angles, allowing it to predict fluid distribution and water trapping in sumps without requiring separate modeling approaches.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The model provides accurate and efficient simulation of fluid flow in multi-segmented wellbores across various inclinations, optimizing hydrocarbon production by determining optimal drilling and completion strategies, reducing computational time, and improving prediction accuracy.
Implementation Method 1
a gas-liquid drift-flux model that accounts for pipe inclinations between −90° and +90° of a multi-segmented wellbore (MSW)
Implementation Method 2
The DF model relates drift velocity to mixture velocity, which is the average velocity of the gas phase and the liquid phase
Implementation Method 3
the porpoising of the horizontal well that often results from a horizontal well drilling can have the side-effect that water can accumulate at various points along the well
Data Source
AI summary
Methods of exploiting a formation containing a reservoir of hydrocarbons utilize a gas-liquid drift-flux (DF) model for a multi-segmented wellbore (MSW). The DF model is provided for use in conjunction with a reservoir simulator. The DF model is configured to account for pipe inclinations of the MSW between −90° and +90° including horizontal or near-horizontal wellbores in addition to vertical and slanted wellbores. The DF model is based on mixture velocity as opposed to superficial velocities, thereby permitting the DF model to be integrated with reservoir models that utilize mixture velocity. The DF model can also be continuous and differentiable over all primary variables.