Research on the Shale Reservoir Sensitivity by Using the Mineral Analysis Method

Area of Science:

• Geochemistry
• Petroleum Engineering
• Material Science

Background:

• Shale reservoirs exhibit complex mineralogy, influencing pore structure and fluid flow.
• Understanding mineral sensitivity to external fluids is crucial for reservoir management.

Purpose of the Study:

• To investigate the impact of slick water and backflow fluid on shale mineral composition.
• To determine the sensitivity of shale pore structure and permeability to specific minerals when exposed to slick water.

Main Methods:

• X-ray diffraction (XRD) experiments were conducted on shale core samples.
• Analysis of mineral composition changes before and after interaction with slick water and backflow fluid.

Main Results:

• Quartz and clay minerals are dominant in shale cores; plagioclase feldspar and rhodochrosite are present in minor amounts.
• Shale mineral composition significantly altered post-fluid interaction, with notable decreases in quartz, kaolinite, and pyrite content.
• Quartz, kaolinite, and pyrite content decreased by an average of 5.1%, 4.6%, and 0.9%, respectively, after slick water exposure.

Conclusions:

• Shale mineralogy is sensitive to external fluids, particularly slick water.
• Quartz, kaolinite, and pyrite are key factors influencing shale pore structure and permeability sensitivity to slick water.