Evaporite-Dolomite Reservoir Analysis for Quantifying Diagenetic Fluids
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Solution Overview
Problem
Current methods for analyzing the diagenesis mechanism of ultra-deep evaporite-dolomite systems in carbonate reservoirs are qualitative and insufficient, limiting the exploration and development of oil and gas reservoirs, particularly in the Sichuan Basin, due to complex diagenesis and multi-stage fluid activities.
Innovation Solution
A method involving the selection of typical drilled wells and field outcrop sections for data collection, combined with advanced analytical techniques such as isotopic analysis and simulation experiments to quantify the diagenetic fluid properties and evolution patterns, establishing a reservoir development model for the ultra-deep evaporite-dolomite paragenesis system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If qualitative research methods are used to study evaporite-dolomite diagenesis, then the complexity of the system can be managed, but the analysis precision and ability to support in-depth exploration is insufficient
Solution Approach 1:
The patent segments the complex diagenesis system into distinct analytical components: evaporite dissolution analysis, dolomite precipitation analysis, fluid inclusion sampling, and isotopic composition measurement. Each component is studied separately using specific analytical methods, allowing precise quantitative analysis of individual processes while managing the overall system complexity.
Solution Approach 2:
The patent transforms qualitative observations into quantitative parameters by measuring specific physical and chemical properties including fluid inclusion temperature, pressure, composition, isotopic ratios (δ18O, δ13C, Sr isotopes), and mineral chemistry. This parameter transformation enables precise mathematical modeling of diagenesis processes.
2Measurement precision
If multiple analytical techniques are combined to achieve complete analysis of diagenetic fluids, then the measurement precision improves, but the operational complexity and time required increases
Solution Approach 1:
The patent performs preliminary micrographic observation and fluid inclusion selection under microscope to identify representative inclusions before extraction. This preliminary sorting and selection process ensures that subsequent complex analyses are performed on pre-screened, high-quality samples, reducing the need for repeated analyses and saving time.
Solution Approach 2:
The patent combines multiple analytical techniques (micrographic observation, fluid inclusion extraction, gas chromatography, mass spectrometry, isotopic analysis) into an integrated analytical workflow. By merging these techniques in a coordinated sequence and using shared sample preparation procedures, the overall analysis time is reduced compared to performing each technique separately.
3Reliability
If comprehensive sampling and analysis of evaporite-dolomite systems are conducted, then the reliability of reservoir formation analysis improves, but the quantity of samples and analytical work required increases
Solution Approach 1:
The patent focuses analysis on specific local features that are most indicative of diagenesis processes: fluid inclusions within specific mineral grains, trace element concentrations in key mineral phases, and isotopic compositions of diagnostic minerals. By concentrating analytical efforts on these locally significant features rather than analyzing all samples uniformly, reliable results are obtained with fewer samples.
Solution Approach 2:
The patent uses fluid inclusions as intermediary carriers that trap and preserve ancient diagenetic fluids. These inclusions serve as mediators between the ancient subsurface environment and modern analysis, allowing indirect but reliable study of historical fluids without needing to collect large quantities of current formation fluids. The inclusions act as natural sample containers that preserve compositional information.
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 provides accurate and complete analysis of the diagenetic fluid characteristics and reservoir formation mechanisms, facilitating the prediction and development of favorable reservoir facies and enhancing the understanding of dolomitization processes, thereby improving the exploration and development of oil and gas reserves.
Implementation Method 1
heating and cooling to determine the homogeneous temperature
Implementation Method 2
measuring race and rare-earth elements, C, O, Sr and Mg isotopes and clumped isotopes of the dolomite
Implementation Method 3
performing a simulation experiment of a water-rock interaction during a main evolution phase according to petrological characteristics in combination with burial history
Data Source
AI summary
A method for quantitatively analyzing the reservoir formation of an ultra-deep evaporite-dolomite paragenesis system is performed as follows. A typical drilling core containing the evaporite-dolomite paragenesis system and a field section are observed. The logging data is subjected to single-factor analysis to determine the planar distribution regularity of the ultra-deep evaporite and the dolomite, and the analysis of sedimentary combination pattern and development evolution regularity is performed. The diagenetic system is determined, and the reservoir formation of the evaporite-dolomite paragenesis system is analyzed. Based on the above technical solutions, the property, the evolution path and the reservoir formation of sedimentation-diagenesis fluids in the evaporite-dolomite paragenesis system can be clarified.