Radial Fishbone SAGD Well Configuration for Steam Distribution
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Solution Overview
Problem
Current steam-assisted gravity drainage (SAGD) methods for heavy oil recovery face challenges such as high water consumption, complex and costly well configurations, and uncertainties in maintaining communication between steam chambers and open-hole ribs, which can lead to reduced efficiency and increased costs.
Innovation Solution
A radial fishbone well configuration with a central well pad featuring horizontal production and injection wells radiating outward, including lateral ribs that reduce the need for conventional steam circulation and optimize steam trap control, allowing for reduced water usage and enhanced oil recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional SAGD methods are used with horizontal wells, then steam can be injected to mobilize heavy oil, but water consumption becomes excessively high (2-3 barrels of water per barrel of oil)
Solution Approach 1:
The well system is segmented into multiple laterals (ribs) branching from a main horizontal well, creating multiple steam injection and production pathways. This segmentation allows more efficient steam distribution throughout the reservoir, reducing the total water needed while maintaining or improving oil recovery rates.
Solution Approach 2:
The invention transitions from conventional horizontal wells to a three-dimensional radial fishbone configuration with laterals extending at various angles and depths. This dimensional expansion creates better reservoir contact and steam distribution efficiency, reducing water consumption while enhancing oil recovery.
2Device complexity
If open-hole ribs are used in fishbone configuration, then well configuration complexity is reduced, but communication between steam chambers and ribs cannot be maintained reliably
Solution Approach 1:
Different sections of the well system have different qualities - the main horizontal well and laterals use open-hole configuration for simplicity, while specific zones require cased and completed sections to maintain reliable steam chamber communication. This local differentiation optimizes both complexity and reliability.
Solution Approach 2:
Steam circulation is performed in advance to preheat the formation and establish communication pathways between steam chambers and laterals before production begins. This preliminary action ensures reliable communication is established while maintaining the simplicity of open-hole ribs.
3Productivity
If conventional steam injection methods are used, then oil can be displaced, but the displaced oil flows to cold areas where viscosity increases and mobility is reduced
Solution Approach 1:
The radial fishbone configuration creates a more uniform temperature distribution throughout the reservoir by distributing steam injection along multiple laterals. This equipotential-like temperature field prevents cold zones from forming, maintaining oil mobility during flow to production wells.
Solution Approach 2:
The three-dimensional radial configuration with laterals at various angles creates multiple flow pathways and prevents oil from being displaced to single cold areas. The dimensional expansion ensures oil remains in warmer zones longer, maintaining mobility.
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 reduces water consumption, simplifies drilling operations, and increases oil recovery rates by establishing immediate fluid communication and optimizing steam distribution, thereby lowering production costs and environmental impact.
Implementation Method 1
steam is injected continuously into the injection well, where it rises in the reservoir and forms a steam chamber. At the interface between the steam chamber and cold oil, steam condenses and heat is transferred to the surrounding oil.
Implementation Method 2
steam is injected continuously into the injection well, where it rises in the reservoir and forms a steam chamber
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 the steam chamber.
Implementation Method 4
Bitumen is a thick, sticky form of crude oil, so heavy and viscous that it will not flow unless heated or diluted with lighter hydrocarbons. At room temperature, bitumen is much like cold molasses. Often times, the viscosity can be in excess of 1,000,000 cP.
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. A central wellpad originates injector and/or producer wells, arranged in a radial pattern, and either or both provided with multilateral wells, thus effectively expanding the coverage.