Preserving Soluble Salt Cements During Subterranean Coring
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Solution Overview
Problem
Traditional coring methods often alter and dissolve soluble salt cements in sedimentary rocks due to thermal changes and water introduction, leading to inaccurate quantification of subsurface rock properties, which affects hydrocarbon reserves and production decisions.
Innovation Solution
The method involves pumping an agent, such as polymers or resin cements, into the subsurface rock formation to preserve soluble salt cements by binding with water and cementing pore space, thereby maintaining the in-situ properties of the rock when coring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional coring methods are used, then core samples can be retrieved for analysis, but soluble salt cements are altered and dissolved due to thermal changes and water introduction
Solution Approach 1:
The patent applies preliminary action by injecting and curing a protective agent in the formation zone before coring operations. This agent penetrates the pore space and precipitates to form a protective barrier that prevents thermal and chemical alterations during subsequent coring, thereby preserving soluble salt cements before the actual measurement process begins.
Solution Approach 2:
The patent uses a protective agent as an intermediary substance between the coring process and the soluble salt cements. This agent acts as a mediator that absorbs thermal energy and prevents direct contact between water and salt cements, thereby protecting the cements from dissolution while allowing core retrieval to proceed.
2Ease of operation
If water is introduced during coring, then cooling and lubrication are provided, but soluble salt cements are dissolved and pore space is altered
Solution Approach 1:
The protective agent serves as an intermediary that allows the coring process to proceed with water-based cooling and lubrication while preventing direct interaction between water and soluble salt cements. The agent forms a barrier that maintains chemical stability of the cements even in the presence of introduced water.
Solution Approach 2:
The patent applies preliminary anti-action by pre-establishing a protective barrier against water before water is introduced during coring. The cured agent in the pore space prevents water from contacting and dissolving salt cements, counteracting the harmful effect of water introduction before it can occur.
3Measurement precision
If thermal changes occur during coring, then rock material is brought to surface for analysis, but soluble salt cements are altered and dissolved
Solution Approach 1:
The protective agent is injected and cured in the formation before coring operations, establishing a thermal buffer in advance. This preliminary action creates a protective environment that mitigates thermal shocks during coring, preventing temperature-induced alterations and dissolution of soluble salt cements before they can occur.
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 approach ensures more accurate representation of formation properties by preventing the loss of soluble salt cements, providing a better understanding of the rock's porosity and permeability, and improving the reliability of hydrocarbon reserve assessments.
Implementation Method 1
The agent may be pumped into a borehole at a pumping pressure to inject the agent a distance into the formation from the borehole
Implementation Method 2
allowing the agent to cure in the pore space
Data Source
AI summary
A method of coring to preserve subterranean soluble salt cements gives careful consideration to the selection and use of drilling fluids, specific logging of the zone of interest, displacing the near wellbore with an agent that when cured has either bound all subterranean water or cemented up all the available pore space, coring of the target formation zone containing the cured agent and retrieval of pressurized core material that allows CT scanning.