Fractured Core Manufacturing with Oil-Water Saturation Control
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Solution Overview
Problem
Existing methods for manufacturing large model fractured cores in petroleum exploration and development fail to maintain original oil-water saturation effectively, often resulting in uneven distribution and high water saturation due to cumbersome processes and the use of high-temperature sintering binders, which are costly and difficult to operate.
Innovation Solution
A direct method involving determining core parameters, preparing oil and water emulsions with specific ratios, and using Portland cement and quartz sand to create a cement slurry that is cast into a mold, allowing for controlled fracture formation and simultaneous establishment of oil-water saturation, enabling the core to withstand high temperature and pressure experiments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy resin or aluminum phosphate is used as cemented mold binders, then the core can withstand high temperature and pressure, but the process becomes complex and costly due to high-temperature sintering requirements
Solution Approach 1:
The patent changes the temperature parameter from high-temperature sintering (required by epoxy resin and aluminum phosphate) to low-temperature curing (40-60°C) by selecting different binder materials. This allows the core to withstand high temperature and pressure experiments while avoiding complex high-temperature processing equipment and procedures.
Solution Approach 2:
The patent employs ordinary Portland cement as a disposable, low-cost binder that does not require expensive high-temperature sintering equipment. The binder serves its purpose during the experiment and can be discarded after use, eliminating the need for costly reusable high-temperature processing systems.
2Shape
If fractures are created first and then saturation is established, then the core structure is formed, but the original water saturation cannot be established due to turbulent fluid flow through fractures
Solution Approach 1:
The patent merges the fracture creation and saturation establishment processes into a single simultaneous operation. By adding fractures to the mold before casting the cement slurry, both the fracture structure and the desired saturation are established together during one casting process, eliminating the sequential approach that causes turbulent flow problems.
Solution Approach 2:
The patent performs preliminary action by pre-arranging the fracture structure in the mold before casting. The fractures are created and positioned in advance, and then the cement slurry with controlled saturation is cast directly into this pre-prepared structure, ensuring both structural integrity and saturation precision are achieved simultaneously.
3Shape
If metal sheet is inserted and then pulled out to form fractures, then the fracture structure is created, but the timing opportunity is difficult to grasp and the process becomes complex
Solution Approach 1:
The patent applies preliminary action by pre-creating the fracture structure in the mold before casting the cement slurry. This eliminates the need for complex post-casting operations like inserting and pulling out metal sheets, making the process easier to operate and more reliable.
Solution Approach 2:
The patent extracts the complex timing-dependent metal sheet insertion and removal operation from the process. Instead of requiring precise timing to insert and pull out metal sheets, the fracture structure is created in advance and maintained throughout the casting process, eliminating the difficult timing requirement.
4Shape
If specific material is placed in mold and then melted, dissolved and volatized by physical means, then fractures are formed, but residues appear and the process becomes cumbersome
Solution Approach 1:
The patent converts the potential harm of using materials that require melting, dissolving, or volatizing into a benefit by selecting fracture-forming materials that leave no residues. The fracture structure is created using materials that can be completely removed or decomposed without leaving harmful substances in the core.
Solution Approach 2:
The patent uses disposable fracture-forming materials that are cheap and can be completely removed after serving their purpose. These materials are inserted to create fractures, then easily removed without leaving residues, avoiding the cumbersome processes of melting, dissolving, or volatizing expensive materials.
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 method allows for simple, cost-effective production of large model fractured cores with controlled fracture distribution and porosity, maintaining original oil-water saturation and simulating reservoir development processes accurately.
Implementation Method 1
mixing oil, water and an emulsifier evenly to prepare an oil-in-water emulsion
Implementation Method 2
the emulsifier accounts for 0.16% to 0.21% of the mass sum of oil and water and is a mixture prepared from sorbitan monooleate (Span-80) and polyoxyethylene sorbitan monooleate (Tween-80)
Implementation Method 3
casting the cement slurry in the core mold to obtain a cement sample; enabling the cement sample to be in a sealed to wait for solidification
Implementation Method 4
taking the core mold down, and cutting the cement sample with a steel wire according to a fracture direction required by an experiment, such that desired fractures are formed
Data Source
AI summary
A direct method for manufacturing a large model fractured core and maintaining original oil-water saturation, including the following steps: (1) determining the volume V, porosity φ, permeability K, oil saturation So, water saturation Sw and the like of a fractured core to be manufactured; (2) preparing simulated oil, and determining the used oil mass mo=Vo×ρo; (3) under the circumstance of no consideration of oil saturation, acquiring the mass of the used water, cement and quartz sand; (4) while establishing oil saturation, acquiring the mass mw of water for manufacturing the core as mw=a−Vo×ρw; (5) mixing oil, water and an emulsifier evenly to prepare an oil-in-water emulsion; (6) adding cement and quartz sand into the emulsion and stirring evenly to obtain cement slurry; (7) when a cement sample is in a semi-solidified state, cutting the cement sample with a steel wire; and (8) solidifying the cement sample to the end.