Fishbone SAGD Well Configuration for Steam Coverage
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Solution Overview
Problem
Conventional Steam Assisted Gravity Drainage (SAGD) methods require significant water and energy for steam production, and multilateral well configurations, while improving oil recovery, are complex and costly to drill and maintain, with uncertainties around rib communication and sand control.
Innovation Solution
The fishbone SAGD well configuration involves multilateral wells that overlap or intersect to cover the area between injector and producer wells, potentially eliminating preheat circulation and reducing well count, with optimized lateral spacing and flow distribution control to enhance steam communication and oil mobilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional SAGD well pairs are used, then steam chamber growth is achieved, but water and energy consumption is high
Solution Approach 1:
The patent segments the conventional single well pair configuration into multiple laterals (ribs) extending from each well. Each lateral independently contributes to steam chamber growth and oil drainage, increasing the effective surface area for heat transfer and oil mobilization without requiring additional well pairs, thereby reducing overall water and energy consumption per barrel of oil recovered.
Solution Approach 2:
The patent transitions from a two-dimensional well pair arrangement to a three-dimensional multilateral configuration. Laterals extend in multiple directions and at different angles from the main wellbore, creating overlapping steam chambers that more efficiently utilize the reservoir volume and reduce the need for excessive steam injection to achieve comparable oil recovery.
2Productivity
If multilateral well configurations are used, then oil recovery is improved, but drilling and maintenance complexity increases
Solution Approach 1:
The patent merges multiple laterals into a single wellbore system sharing common infrastructure (surface equipment, completion string, stimulation treatments). This consolidation achieves the oil recovery benefits of multiple wells while reducing the operational complexity and cost associated with drilling, completing, and maintaining separate multilateral wells.
Solution Approach 2:
The main wellbore and associated equipment serve multiple functions by supporting several laterals for steam injection and oil production simultaneously. This multi-functionality allows a single well configuration to perform the work of multiple conventional well pairs, improving oil recovery without proportionally increasing operational complexity.
3Reliability
If laterals are extended to cover more area, then steam communication is improved, but drilling cost and complexity increase
Solution Approach 1:
The patent implements laterals that extend partially across the reservoir rather than fully spanning the entire distance between well pairs. This partial coverage is sufficient to establish effective steam communication and mobilize oil in the critical zones, achieving reliable steam chamber growth without the excessive drilling costs and complexity of full-span laterals.
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 configuration accelerates oil recovery, reduces water and energy consumption, and lowers production costs by simplifying well operations and reducing equipment needs, while maintaining effective steam chamber growth and oil mobilization.
Implementation Method 1
steam is injected continuously into the injection well, where it rises in the reservoir and forms a steam chamber. With continuous steam injection, the steam chamber will continue to grow upward and laterally into the surrounding formation. At the interface between the steam chamber and cold oil, steam condenses and heat is transferred to the surrounding oil.
Implementation Method 2
At the interface between the steam chamber and cold oil, steam condenses and heat is transferred to the surrounding oil.
Implementation Method 3
This heated oil becomes mobile and drains, together with the condensed water from the steam, into the production well due to gravity segregation within steam chamber.
Data Source
AI summary
The present disclosure relates to a particularly effective well configuration that can be used for SAGD and other steam based oil recovery methods. Fishbone multilateral wells are combined with SAGD, effectively expanding steam coverage. Preferably, an array of overlapping fishbone wells cover the pay, reducing water use and allowing more complete production of the pay.