Permeable Cement Stone Fracturing Method
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Solution Overview
Problem
Conventional fracturing methods for non-conventional oil and gas layers face issues such as environmental pollution, poor stimulation efficiency, high hydraulic horsepower requirements, large well site occupation, and high costs due to the use of large-scale water-based fluids and proppants, leading to short effective duration and significant environmental risks.
Innovation Solution
A permeable cement stone fracturing method using a mixture of supercritical carbon dioxide and cement slurry is injected into the oil and gas layer to form a permeable cement stone, eliminating the need for conventional proppants and fluids, reducing water usage, and minimizing equipment and site requirements, while enhancing stimulation effectiveness and environmental safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional water-based fracturing fluid and proppant are used, then fracture support is achieved, but environmental pollution and disposal costs increase significantly
Solution Approach 1:
The invention extracts and eliminates the harmful water-based fracturing fluid and proppant from the system, replacing them with a biodegradable organic solvent-based fracturing fluid and soluble proppant. This extraction of harmful substances resolves the contradiction by maintaining fracture support functionality while eliminating environmental pollution and disposal issues.
Solution Approach 2:
The invention changes the chemical parameters of the fracturing fluid from water-based to organic solvent-based, and changes the proppant from insoluble ceramic particles to soluble materials. This parameter transformation allows the system to achieve fracture support while the proppant dissolves over time, eliminating environmental contamination and disposal costs.
2Strength
If spherical ceramic proppant is used, then fracture support is provided, but the proppant is easily crushed and embedded into soft strata, resulting in short effective duration
Solution Approach 1:
The invention changes the physical and chemical parameters of the proppant from hard, insoluble ceramic spheres to soluble materials with controlled dissolution rates. This parameter change allows the proppant to provide initial strong support while gradually dissolving to maintain long-term effectiveness, resolving the contradiction between strength and duration.
Solution Approach 2:
The invention introduces a dynamic system where the proppant properties change over time through controlled dissolution. The proppant transitions from a solid support structure to a dissolving agent, providing both immediate mechanical support and sustained chemical stimulation, thereby achieving both strength and extended duration.
3Productivity
If large-scale water-based fracturing fluid is used, then fracture stimulation is achieved, but large hydraulic horsepower is required
Solution Approach 1:
The invention changes the fluid parameters from water-based to organic solvent-based fracturing fluid with optimized viscosity and density characteristics. This parameter optimization reduces the hydraulic horsepower required while maintaining effective fracture stimulation, resolving the contradiction between productivity and power consumption.
4Productivity
If conventional fracturing equipment and materials are used, then fracturing operation is performed, but large well site area is occupied
Solution Approach 1:
The invention extracts and eliminates the need for large-scale water storage tanks, proppant handling equipment, and flow-back fluid disposal systems from the well site. By using organic solvent-based fluid and soluble proppant that eliminate flow-back issues, the system reduces well site occupation while maintaining full fracturing operation capability.
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 achieves zero flow-back fluid, reduced water and material usage, lower costs, improved stimulation duration, and better environmental protection by forming a stable permeable cement stone that supports fractures and connects wellbores effectively, reducing geological hazards and pollution.
Implementation Method 1
a second mixture of supercritical carbon dioxide (SC—CO2) and cement slurry of the oil well is injected into the reticulate artificial fracture and the natural fracture
Implementation Method 2
a portion of the carbon dioxide dissolves in bound water and free water to form carbonic acid to erode, dissolve and leach the air pore and pore throat of the cement stone
Implementation Method 3
after final setting and solidification of the cement slurry
Implementation Method 4
forming a permeable cement stone automatically, supporting and fixing the artificial fracture and the natural fracture
Implementation Method 5
a portion of the carbon dioxide dissolves in bound water and free water to form carbonic acid to erode, dissolve and leach the air pore and pore throat of the cement stone
Data Source
AI summary
A permeable cement stone fracturing exploitation method for non-conventional oil and gas layer comprising the following processes: transporting and storing a supercritical carbon dioxide to a well site; selecting, transporting, and storing an oil well cement and admixtures to the well site; mixing the oil well cement and the admixtures into a first mixture, forming a cement slurry; pumping the supercritical carbon dioxide and the cement slurry respectively into a high pressure mixer; automatically mixing the supercritical carbon dioxide and the cement slurry into a second mixture by the high pressure mixer; continuously on-line monitoring and temporarily storing the second mixture; and injecting the second mixture into the non-conventional oil and gas layer for fracturing to form a reticulate artificial fracture; the second mixture is automatically heated, pressure reduced, gasified, solidified, carbonic acid dissolved and eroded, leached to form the a permeable cement stone.