Staged Production Wells for In Situ Combustion Front Stability
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Solution Overview
Problem
In situ combustion methods for oil recovery face challenges such as loss of ignition, lack of control, and inadequate reservoir characterization, leading to suboptimal recovery rates and cumulative recoveries due to instability of the combustion front and undesired increases in oil viscosity.
Innovation Solution
The method involves configuring injection and production wells with deviated sections to facilitate gravity-driven segregation of liquids and gasses, allowing for controlled propagation and recovery of hydrocarbons, with oxidant injection to maintain an exothermic reaction and prevent choking, using vertical separation and staged well placement to differentiate gas and hydrocarbon removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxidant injection is used to propagate combustion through the formation, then hydrocarbon recovery is improved through thermal cracking, but combustion front stability deteriorates leading to loss of ignition and inadequate control
Solution Approach 1:
The production well is divided into multiple sections with different intake depths. The first section extends to a first depth and the second section extends to a second depth greater than the first depth. This segmentation allows different sections to produce different phases (gasses from upper section, liquids from lower section), stabilizing the combustion front while maintaining high recovery rates through controlled exothermic reactions.
2Temperature
If higher temperatures are used to increase thermal cracking of oil, then lighter oil is produced, but endothermic oxidation reactions increase causing undesired increases in oil viscosity
Solution Approach 1:
Different sections of the production well are assigned different functions based on their depth. The first section (upper) is optimized for producing gasses and the second section (lower) for producing liquids. This local differentiation ensures that thermal cracking occurs at optimal temperatures while preventing endothermic reactions from increasing viscosity, as each section operates in its optimal temperature and pressure regime.
3Device complexity
If single well production is used to recover hydrocarbons, then device complexity is reduced, but recovery efficiency deteriorates due to inability to separate gas and liquid production
Solution Approach 1:
The production well is segmented into multiple sections with different intake depths. The first section intakes fluids at a first depth while the second section intakes fluids at a second depth. This segmentation enables separate production of gasses and liquids through the same wellbore, significantly improving recovery efficiency without requiring multiple separate wells, thus balancing device complexity with productivity.
Solution Approach 2:
The solution adds a vertical dimension to production by creating sections at different depths within the same well. The first section operates at an upper depth level while the second section operates at a lower depth level. This vertical differentiation allows simultaneous production of different phases (gasses and liquids) through a single well, improving recovery efficiency while avoiding the complexity of multiple separate wells.
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
This approach enhances oil recovery by maintaining a stable combustion front, increasing thermal cracking, and optimizing hydrocarbon production rates, with gasses forming a significant portion of production from one well and hydrocarbons from another, improving overall recovery efficiency.
Implementation Method 1
injecting oxidant into the injection well to propagate combustion
Implementation Method 2
oxidation occurring is an exothermic reaction
Implementation Method 3
gravity segregation creates an interface between liquids and gasses in the formation
Implementation Method 4
beneficial thermal cracking of the oil to make the oil lighter
Data Source
AI summary
Methods and apparatus relate to in situ combustion. Configurations of the injection and production wells facilitate the in situ combustion. Utilizing wet combustion for some embodiments promotes heat displacement for hydrocarbon recovery with procedures in which one or more of the production and injection wells are configured with lengths deviated from vertical. In some embodiments for either dry or wet combustion, at least the production wells define intake lengths deviated from vertical and that are disposed at staged levels within a formation. Each of the productions wells during the in situ combustion allow for recovery of hydrocarbons through gravity drainage. Vertical separation between the intake lengths of the production wells enables differentiated and efficient removal of combustion gasses and the hydrocarbons.