Well Integrity Assessment via Fluid Composition Analysis
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Solution Overview
Problem
Existing methods for assessing the integrity of oil and gas wells are limited in identifying the sources of externally sourced fluids within the annuli and often require intervention or suspension of production.
Innovation Solution
A method that involves collecting and analyzing subsurface fluids exiting from the well, determining their origin by comparing their composition features with those of gases released from mechanically crushed subsurface rock samples of known origin, thereby identifying leakage sources and migration pathways without interrupting production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods for assessing well integrity are used, then the integrity status can be evaluated, but the sources of externally sourced fluids within the annuli cannot be precisely identified and production interruption is required
Solution Approach 1:
The method performs preliminary analysis of fluid composition features (gas chromatography, isotopic ratios) during routine operations. By pre-characterizing fluid signatures from different subsurface zones using rock sample crushing, the system enables real-time identification of fluid origins without interrupting production, resolving the contradiction between measurement precision and productivity
Solution Approach 2:
The invention replaces traditional mechanical intervention methods (downhole tools, well suspension) with analytical chemistry methods (gas chromatography, mass spectrometry). By substituting mechanical assessment with chemical fingerprinting of fluids, the system achieves precise origin identification while maintaining continuous production
2Reliability
If downhole tools with physical sensors are used to identify cement quality and corrosion, then some well conditions can be detected, but the tools require intervention and production suspension
Solution Approach 1:
The method extracts fluid samples from the wellhead during normal operations and analyzes their composition in a laboratory setting. By taking the analysis function out of the downhole environment and performing it on surface-collected samples, the system achieves reliable well condition detection without requiring complex downhole tools or production suspension
Solution Approach 2:
The invention uses fluid composition analysis as an intermediary indicator of well integrity conditions. Instead of directly measuring cement quality or corrosion with physical sensors, the method infers these conditions from the chemical fingerprint of fluids, simplifying operations while maintaining detection reliability
3Loss of information
If traditional well integrity assessment methods are used, then general annulus pressure monitoring is possible, but the specific subsurface origin of pressure-building gases cannot be determined
Solution Approach 1:
The method changes the measurement parameters from simple pressure monitoring to detailed fluid composition analysis (molecular composition, isotopic ratios). By analyzing these chemical parameters of annulus gases and comparing them with crushed rock sample signatures, the system determines specific subsurface origins without excessive complexity
Solution Approach 2:
The invention performs preliminary crushing and analysis of rock samples from various subsurface zones to establish a reference database of gas compositions. This pre-established reference enables direct comparison with annulus gases during operations, providing complete origin information through a systematic but manageable process
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 precise, reliable, and non-invasive determination of the subsurface origin of fluids causing annular pressure build-up, enabling effective identification of leakage sources and potential migration pathways, thus enhancing well integrity assessment.
Implementation Method 1
determining the subsurface origin of said exiting fluids by using the composition features of released fluids, in particular of released gasses, that are released following to the application of a mechanical action, preferably a crushing action, on subsurface rock samples
Data Source
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AI summary
Method for assessing the status of a well (W) or of a similar borehole extending from a surface (S) downward into a subsurface, preferably for assessing the integrity status of an oil and gas well, comprising: - collecting/sampling (101) of subsurface fluids exiting from the subsurface of said well or of a nearby well, - determining (120) the subsurface origin of said subsurface exiting fluids by using the composition features of released fluids, in particular of released gasses, that are released following the application of a mechanical action, preferably a crushing action, on subsurface rock samples having known subsurface origins in said well or in a nearby well.