Polyhalite Smart Water for Carbonate Wettability and Oil Recovery
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Solution Overview
Problem
Carbonate reservoirs face challenges in oil recovery due to low matrix permeabilities, natural fractures, and unfavorable wettability, leading to low oil recovery rates and water fingering, despite holding significant hydrocarbon reserves.
Innovation Solution
A liquid solution for enhanced oil recovery (EOR) is developed, comprising Polyhalite, NaCl, and SiO2 dissolved in low salinity water, which alters the wettability of carbonate reservoirs by introducing beneficial ions like calcium, magnesium, and sulfate, promoting spontaneous imbibition and oil mobilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water injection is performed in carbonate reservoirs with neutral to oil-wet wettability, then the reservoir can be flooded to displace oil, but water fingering occurs and early water breakthrough reduces oil recovery efficiency
Solution Approach 1:
The patent changes the chemical composition parameters of the injection brine by adding specific concentrations of calcium chloride (0.01-1 M), magnesium chloride (0.01-1 M), and sodium sulfate (0.01-1 M) to alter the wettability of carbonate reservoirs from neutral/oil-wet to water-wet, thereby controlling water breakthrough and improving oil recovery
Solution Approach 2:
The patent introduces smart water as an intermediary substance that mediates between the injection water and the carbonate reservoir. The smart water contains specific ions (Ca2+, Mg2+, SO42-) that act as intermediaries to modify the surface properties of carbonate rocks, enabling better oil displacement without early water breakthrough
2Productivity
If carbonate reservoirs are flooded with conventional water, then oil can be displaced, but unfavorable wettability limits capillary forces and reduces water imbibition into the rock matrix
Solution Approach 1:
The patent changes the wettability parameter of the carbonate reservoir by modifying the ionic composition of injection water. Adding calcium, magnesium, and sulfate ions alters the interfacial tension and contact angle, transforming the reservoir from neutral/oil-wet to water-wet, thereby enhancing capillary forces for water imbibition
Solution Approach 2:
The patent replaces mechanical displacement alone with a combined mechanism involving chemical modification of surface properties. The smart water chemically modifies the carbonate surface to enhance capillary forces, substituting pure mechanical flooding with a chemically-enhanced process
3Ease of operation
If low salinity water is used for injection, then wettability alteration may occur, but the ionic composition must be precisely controlled to achieve optimal results
Solution Approach 1:
The patent defines specific parameter ranges for ionic composition (Ca2+: 0.01-1 M, Mg2+: 0.01-1 M, SO42-: 0.01-1 M) that achieve wettability alteration. By establishing these quantitative guidelines, the complex process of smart water preparation becomes more manageable and reproducible
Solution Approach 2:
The patent creates a composite injection fluid (smart water) combining multiple ions in specific proportions. This composite approach simplifies operation by providing a ready-mixed solution with optimized ionic composition, rather than requiring separate control of each ion
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 solution enhances oil recovery by altering wettability to a more water-wet state, increasing capillary forces and delaying water breakthrough, thereby improving oil production efficiency in carbonate reservoirs.
Implementation Method 1
The composition of the injection brine is crucial for efficiency of the wettability of the carbonate surface... It is important to modify the carbonate reservoir surface to water wet in order to increase oil recovery
Implementation Method 2
Increased capillary forces will promote spontaneous imbibition of brine from fractures into the matrix and mobilize trapped oil
Data Source
AI summary
A liquid solution for the recovery of oil from carbonate reservoirs, the solution including a solid chemical composition including Polyhalite in a weight range of 70 to 94.9%, NaCl in a weight range of 5 to 29.9%, and SiO2 in a weight range of 0.1 to 5%, the solid chemical composition being dissolved in water, which may include sea water, diluted sea water, desalinated seawater, produced water, aquifer water, river water, surface water, fresh water, or distilled water, where the solution is prepared by dissolving 1-10 grams of the solid chemical composition per liter of water.