Reservoir Stimulation Fluid for Permeability and Wettability Control
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Solution Overview
Problem
Current stimulation techniques for unconventional hydrocarbon reservoirs face challenges in enhancing permeability and water wettability, particularly at varying temperatures, and often result in precipitate deposition, which hinders effective oil and gas recovery.
Innovation Solution
A self-initiating, self-reactive treatment fluid is injected into the reservoir, comprising an aqueous solution of an ammonium salt capable of exothermic oxidation to generate heat and gas, an oxidizing agent, a corrosion inhibitor, a low molecular weight carboxylic acid, and high salinity brine with divalent ions, along with optional surfactants, to alter wettability and increase permeability without precipitate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acid solution is pumped into the formation at high temperature to react with formation minerals, then new flow paths are created for hydrocarbon recovery, but precipitate deposition occurs which hinders effective oil and gas recovery
Solution Approach 1:
The patent converts the harmful precipitate deposition into a beneficial effect by using the precipitation reaction to deposit desirable minerals that improve permeability and create flow paths while simultaneously preventing the deposition of harmful scales. The acidizing process is designed to precipitate beneficial minerals in controlled amounts that enhance reservoir productivity rather than hinder it.
Solution Approach 2:
The patent employs parameter changes by adjusting the composition, temperature, and flow rate of the acidizing fluid to control the precipitation reactions. By optimizing these parameters, the process achieves effective rock dissolution and flow path creation while minimizing harmful precipitate deposition that would reduce permeability.
2Productivity
If stimulation techniques are used to enhance permeability and alter wettability, then hydrocarbon flow is improved, but the processes become costly and technically challenging
Solution Approach 1:
The patent applies multi-functionality by designing a single acidizing fluid composition that simultaneously achieves multiple objectives: dissolving formation minerals to create flow paths, altering rock wettability to enhance hydrocarbon recovery, controlling precipitate deposition to maintain permeability, and preventing scale formation. This consolidates multiple stimulation functions into one integrated process.
Solution Approach 2:
The patent uses composite acidizing fluid compositions that combine multiple chemical components with complementary functions. The composite formulation includes acids for mineral dissolution, surfactants for wettability alteration, and precipitate control agents, all working together in a single fluid system to achieve enhanced recovery while simplifying the overall stimulation process.
3Productivity
If reactive chemicals are injected to generate in-situ gas and heat to reduce heavy oil viscosity, then oil mobility is enhanced, but the treatment complexity increases
Solution Approach 1:
The patent merges the functions of viscosity reduction and flow path creation into a single acidizing process. By combining the mineral dissolution function with in-situ gas generation and heat production in one treatment fluid system, the patent achieves heavy oil mobility enhancement without requiring separate stimulation operations, thereby reducing overall treatment complexity.
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 treatment fluid effectively generates heat and nitrogen gas, altering wettability and permeability, enhancing oil and gas recovery by thinning heavy oil and removing near-wellbore damage, while maintaining well performance and equipment cleanliness.
Implementation Method 1
an aqueous solution of an ammonium salt capable of exothermic oxidation to generate heat and gas
Implementation Method 2
an oxidizing agent capable of oxidizing the ammonium salt
Data Source
AI summary
A stimulation fluid including (i) an aqueous solution of an ammonium salt capable of being exothermally oxidized to produce heat and gas, (ii) an aqueous solution of an oxidizing agent capable of oxidizing the ammonium salt; (iii) a water-soluble inorganic acid salt and/or an organic carboxylic acid salt of a tertiary amine; (iv) a low molecular weight carboxylic acid; and (v) a high salinity brine containing divalent metal ions; and (vi) optionally, a surfactant.