Lateral Wellbore Configurations for Gravity Drainage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Interbedded layers with limited permeability in hydrocarbon-bearing formations act as barriers to vertical fluid flow, compartmentalizing reservoirs and hindering economic oil recovery through steam-assisted gravity drainage processes, as vertical and horizontal wells fail to promote effective gravity drainage.
Innovation Solution
The method involves forming horizontal injection and production wells with laterals that intersect a low-permeability stratum, allowing steam to flow preferentially through the injection laterals and hydrocarbons to drain through the production laterals, creating fluid flow paths that reduce counter-current flow and enhance gravity drainage across separated reservoirs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vertical wells are used to contact thin reservoir layers, then the wells can reach the reservoirs, but the production rates are not economic due to the low permeability barriers
Solution Approach 1:
The patent transitions from vertical wellbores to horizontal wellbores, changing the spatial dimension of well placement. Horizontal wellbores allow the well to traverse along the reservoir layer horizontally, maximizing contact with the hydrocarbon-bearing formation while avoiding the low-permeability shale barriers that constrain vertical flow paths.
Solution Approach 2:
The wellbore is segmented into multiple laterals extending at different vertical positions through the low-permeability stratum. This segmentation creates multiple parallel flow paths through the barrier layer, increasing the total effective flow area and enabling economic production rates by distributing the flow across multiple segments rather than a single vertical path.
2Area of stationary object
If slant wells or multi-horizon wells are used to expose more reservoir, then the reservoir contact area increases, but gravity drainage processes are not effectively promoted
Solution Approach 1:
The patent employs horizontal wellbores oriented parallel to the reservoir layers, creating a dimensional configuration that maximizes horizontal reservoir contact while maintaining the gravity drainage mechanism. This horizontal orientation allows steam injection and hydrocarbon production to occur along the gravity-driven flow path, effectively promoting gravity drainage unlike slant or multi-horizon configurations.
3Device complexity
If laterals are positioned symmetrically through the stratum, then the structure is balanced, but counter-current flow reduces the efficiency of steam injection and hydrocarbon production
Solution Approach 1:
The patent positions the injector section lateral closer to the injector wellbore and the producer section lateral closer to the producer wellbore, creating an asymmetric configuration through the low-permeability stratum. This asymmetric placement ensures that steam injected through the injector lateral can more effectively reach the hydrocarbons, while the producer lateral is optimally positioned to receive the heated hydrocarbons, thereby reducing counter-current flow and improving overall fluid flow efficiency.
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 increases hydrocarbon recovery by facilitating more fluid crossing through the stratum from the injection laterals and hydrocarbon drainage through the production laterals, improving the economic viability of oil recovery processes.
Implementation Method 1
injection of steam and/or other thermal solvent increases mobility of the oil within the formation via an exemplary process known as steam assisted gravity drainage (SAGD)
Implementation Method 2
Production fluid flows from solids that remain in the formation and thus includes the oil and condensate from the steam
Implementation Method 3
interbedded layers, such as shale, with limited permeability in the formation act as barriers to vertical flow
Data Source
AI summary
Methods and systems relate to recovering hydrocarbons from within formations in which hydrocarbon bearing reservoirs are separated from one another by a fluid flow obstructing natural stratum. Relative to the reservoirs, the stratum inhibits or blocks vertical fluid flow within the formation. Lateral bores divert from lengths of injector and producer wells along where extending in a horizontal direction. These bores pass upward through the formation to intersect the stratum and provide an array of fluid flow paths through the stratum. In a side direction perpendicular to the horizontal direction of the wells, the lateral bores from the injector well pass through the stratum inside of where the lateral bores from the producer well pass through stratum. Fluid communication established by the bores limits counter-current flow through the bores in processes that rely on techniques such as gravity drainage.