Recovery Enhancing Fluid System for Fractured Reservoirs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In unconventional reservoirs, particularly low permeability fractured carbonate reservoirs, existing Enhanced Oil Recovery (EOR) methods such as water injection and cyclic steam injection are ineffective in mobilizing oil due to high permeability fractures, leading to significant oil being left in place, necessitating new compositions and methods to enhance oil recovery.
Innovation Solution
A Recovery Enhancing Fluid System (REFS) comprising a phosphonoalkyl moiety-based recovery enhancing agent, surfactant, miscible fluid, and base fluid is introduced into wellbores, utilizing liquified natural gas to pump energized fluids, which increases water imbibition and wettability of rock surfaces, facilitating the mobilization of oil from the matrix through cyclic injection and production processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water injection is used for pressure support in low permeability fractured carbonate reservoirs, then pressure support is provided, but the water follows existing fractures and does not effectively sweep the rock matrix, leaving most oil in place
Solution Approach 1:
The patent changes the chemical parameters of the injection fluid by adding surfactants that alter interfacial tension and wettability characteristics. This modifies how the fluid interacts with the rock matrix and oil, enabling effective sweep of previously inaccessible oil in low permeability fractured carbonate reservoirs
Solution Approach 2:
The patent uses composite fluid systems combining surfactants, polymers, and other chemical additives with base fluids. This composite approach creates a multifunctional injection fluid that can simultaneously handle pressure support, improve wettability, reduce interfacial tension, and enhance oil mobility in fractured reservoirs
2Productivity
If cyclic steam injection is used for EOR, then pressure support and heating are provided, but the method is not effective in mobilizing oil due to high permeability fractures
Solution Approach 1:
The patent changes the thermal and chemical parameters by using surfactant-enhanced injection fluids that can mobilize oil at lower temperatures and pressures. This avoids the energy-intensive steam injection process while achieving similar or better oil mobilization results in fractured reservoirs
Solution Approach 2:
The patent replaces the thermal-mechanical steam injection system with a chemical-based surfactant injection system. This substitution uses chemical mechanisms (surface tension reduction, wettability alteration) instead of thermal-mechanical processes to achieve oil mobilization, significantly reducing energy consumption
3Ease of manufacture
If multi-well pads are used to reduce surface facility costs, then operating costs and surface facility costs are reduced, but the high permeability fractures still bypass the oil in the matrix
Solution Approach 1:
The patent changes the fluid properties by incorporating surfactants that fundamentally alter how the injection fluid interacts with oil and rock surfaces. This enables effective oil recovery from the matrix even in multi-well pad configurations where fractures would otherwise bypass the oil
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 REFS significantly increases oil recovery by enhancing water imbibition and wettability, allowing for more effective oil extraction from tight reservoirs, potentially doubling or tripling the oil extracted from calcite-rich reservoirs, and extending the production life of wells by improving reservoir pressure and hydrocarbon recovery across multi-well fields.
Implementation Method 1
The REFS chemistry to induce higher rates of water imbibition into reservoir rocks
Implementation Method 2
water-wet the rock surface to mobilize more oil from the matrix
Data Source
AI summary
A method of producing natural resources from a wellbore penetrating a subterranean formation with a Huff and Puff process comprising: (a) placing a recovery enhancing fluid system into the wellbore during an injection (Huff) period of time wherein placing the recovery enhancing fluid system comprises injecting under pressure; (b) ceasing injection of the recovery enhancing fluid system and allowing the composition to soak in the subterranean formation for a soak period of time; (c) producing fluids from the subterranean formation during a production (Puff) period of time; and (d) optionally repeating steps (a) to (c) for a plurality of Huff, soak, and Puff periods of time, respectively.