Pressure-Preserved Coring Assembly for In-Situ Core Analysis
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Solution Overview
Problem
Existing pressure-preserved coring techniques fail to maintain the in-situ pressure state of rock cores during extraction, leading to changes in physical and fluid distribution characteristics, which hinders accurate reservoir evaluation and exploration.
Innovation Solution
A pressure-preserved coring tool with a differential assembly and a pressure-preserving inner cylinder assembly that maintains the rock core's pressure state by using shear pins and fluid channels to control the movement of components, allowing for in-situ analysis with a nuclear magnetic resonance analyzer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure-preserved coring technique is used to extract rock cores, then the rock core can be taken out with original formation pressure, but the original state characteristics cannot be observed and evaluated because pressure must be released before analysis
Solution Approach 1:
The coring tool is divided into separate functional modules: a pressure-preserving inner cylinder assembly that maintains formation pressure, and an outer cylinder with differential assembly for controlled movement. This segmentation allows the rock core to remain pressurized during extraction while enabling separate analysis testing operations.
Solution Approach 2:
The inner cylinder assembly acts as an intermediary chamber that isolates the rock core from the external environment. It maintains the formation pressure state within its confines, serving as a mediator between the pressurized rock core and the analysis testing equipment, eliminating the need to release pressure before analysis.
2Ease of operation
If pressure is released before rock core analysis, then analysis testing can be performed, but the original state of the reservoir changes and real reservoir information cannot be obtained
Solution Approach 1:
The inner cylinder assembly is pre-configured to maintain formation pressure before analysis testing begins. This preliminary pressure maintenance ensures that the rock core remains in its original state throughout the extraction and analysis process, preventing any changes to reservoir characteristics before measurement.
Solution Approach 2:
The system maintains the pressure parameter of the rock core constant throughout the entire process. By keeping pressure unchanged from formation conditions to analysis testing, the original state characteristics are preserved, enabling accurate measurement of real reservoir information without degradation.
3Productivity
If drilling and exploitation process is applied to natural gas hydrates, then oil and gas resources can be extracted, but the stability of hydrates in seabed formation is affected and physical and mechanical properties of the formation change
Solution Approach 1:
The inner cylinder assembly extracts and isolates the rock core containing natural gas hydrates from the drilling environment. By taking out the core in a controlled manner while maintaining formation pressure, the system prevents the disruptive effects of conventional drilling on hydrate stability and preserves the original physical and mechanical properties of the formation.
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
Preserves the rock core's pressure state during extraction, enabling accurate nuclear magnetic resonance testing to obtain critical reservoir information, supporting efficient oil and gas resource exploration and development.
Implementation Method 1
when the pressure in the pressure cavity reaches a first predetermined value, the first shear pin will be cut off, so that the differential joint will move along the first pitching joint toward the first end of the outer cylinder
Implementation Method 2
obtain important information, such as physical properties and fluid distribution characteristics of the reservoir, under in-situ formation conditions with appropriate analysis and testing methods
Data Source
AI summary
The present invention relates to the field of drilling coring devices. Disclosed are a pressure-preserved coring tool, a use method, and a reservoir analysis method. The pressure-preserved coring tool comprises an outer cylinder (1), a differential assembly (2), a pressure-preserving inner cylinder assembly (4), and a seal assembly (5). The differential assembly is configured to be able to drive the pressure-pre-serving inner cylinder assembly to move upwards relative to the seal assembly, so that the seal assembly seals the inner cylinder assembly for accommodating a rock core (8). Therefore, in the process of taking out a drilled rock core to the ground, the pressure state of the rock core in an in-situ formation can be preserved in the inner cylinder assembly, so that important information, such as physical properties and fluid distribution characteristics of reservoirs under in-situ formation conditions, is obtained by means of, for example, a nuclear magnetic resonance-based analysis and test method, thereby supporting efficient exploration and development of oil and gas resources.