Research on the Optimization for Acidification Modification Scheme Considering Coal's Wettability Based on the...

Area of Science:

• Geochemistry
• Petroleum Engineering
• Materials Science

Background:

• Acidification is crucial for coalbed methane (CBM) extraction from low-permeability coal seams.
• The effectiveness of acidification hinges on selecting an optimal treatment scheme.

Purpose of the Study:

• To propose an improved Analytic Hierarchy Process-Technique for Order Preference by Similarity to Ideal Solution (AHP-TOPSIS) method for optimizing coal wettability modification.
• To identify the optimal acidification conditions for enhancing CBM extraction.

Main Methods:

• Developed an evaluation index system with coal wettability as the target and functional groups as indicators.
• Utilized adsorption energy of functional groups for water molecules to assign index weights.
• Applied the improved AHP-TOPSIS method to evaluate nine acidification schemes based on test results.

Main Results:

• The significance of evaluation indexes was ranked: aromatic structures > hydroxyl groups > aliphatic functional groups > oxygen-containing functional groups.
• The optimal acidification scheme identified was 4% hydrofluoric acid (HF) concentration and a 6-hour reaction time.
• The AHP-TOPSIS method's scheme ranking showed high agreement with water adsorption test results.

Conclusions:

• The improved AHP-TOPSIS method effectively evaluates and selects optimal acidification schemes for coal wettability modification.
• The optimal scheme significantly reduces coal's water adsorption capacity.
• This approach has the potential to increase CBM production by improving coal seam properties.