Innovative assessment of CO2 storage potential in China's shale oil fracturing: A storage index-well layout approach

Abstract

As global efforts to mitigate climate change intensify, CO₂ storage in shale oil reservoirs presents a promising avenue for reducing greenhouse gas emissions while enhancing oil recovery. However, accurate assessment of storage potential remains challenging, particularly in China's diverse shale oil basins. This study introduces the Storage Index-Well Layout (SI-WL) method, a novel approach for evaluating CO₂ storage potential in shale oil reservoirs, and applies it to 12 major basins in China. Comparing this method with traditional and improved US-DOE methods demonstrates its superior reliability in estimating storage capacity under current technological conditions. Our analysis reveals a cumulative CO₂ storage potential of 5.69 × 10⁸ t of liquid CO₂ across the studied basins, with the Bohai Bay Basin showing the highest capacity at 1.87 × 10⁸ t. Scenario analysis from 2025 to 2060 identifies key factors influencing storage potential, including the proportion of wells using CO₂ fracturing and fracturing fluid performance. While current practices in China's shale oil CO₂ fracturing achieve effective results, improving liquid CO₂'s viscosity and sand-carrying performance remains a significant challenge. This research provides valuable insights for shale oil CO₂ fracturing development and CO₂ emission reduction strategies, suggesting that technological advancements could significantly enhance CO₂ storage in the shale oil industry.