Genesis Mechanism of Low Resistivity in the Lower Cambrian Qiongzhusi Formation Shale and Its Response Characteristics to Pore Structure - Take the Z201 Well as an Example
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Summary
This summary is machine-generated.Highly mature graphitized organic matter and formation water create conductive pathways in low-resistivity shale reservoirs. Increased graphitization reduces resistivity, impacting pore structure and guiding sweet spot identification for shale gas exploration.
Area Of Science
- Geochemistry
- Petroleum Geology
- Sedimentology
Background
- Extensive low-resistivity shale reservoirs discovered in Sichuan Basin's Qiongzhusi Formation present exploration challenges due to variable gas production.
- Identifying optimal exploration and development sweet spots is hindered by inconsistent reservoir performance.
Purpose Of The Study
- Investigate the genesis mechanisms of low-resistivity shale reservoirs.
- Analyze the relationship between pore structure and reservoir characteristics.
- Provide theoretical guidance for shale gas exploration in the Sichuan Basin.
Main Methods
- Core resistivity measurements
- Thermal simulations
- Raman spectroscopy analysis of shale samples.
Main Results
- Highly mature graphitized organic matter (HMG-OM) and formation water are primary drivers of low resistivity.
- Increased graphitization correlates with decreased resistivity and increased maturity.
- Shale exhibits mineralogical changes (quartz breakage, mineral transformation, calcite/pyrite dissolution) and increased inorganic porosity.
- Organic matter pore development is negatively impacted by OM graphitization, leading to pore deformation and collapse.
Conclusions
- The Weiyuan-Ziyang area is identified as a key region for future shale gas development in the Qiongzhusi Formation.
- Understanding the interplay between organic matter graphitization, pore structure, and resistivity is crucial for successful shale gas exploration.
- Findings offer theoretical guidance for optimizing shale gas exploration and development strategies in the Sichuan Basin.
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