Appraising Carbon Geological Storage Potential in Unconventional Reservoirs Using Well-Testing Method: Engineering Parameters Analysis

Abstract

Most of work focus on influences of reservoir parameters of depleted shales on carbon storage capacity. This is useful for selecting a good candidate as a repository. However, engineering parameters of shales are also important factors for carbon sequestration. So, necessary work is still needed. Following a detailed introduction of a trilinear flow model for carbon sequestration (Chen et al., 2016), this paper continues to study impacts of engineering parameters on carbon storage potential. Firstly, the methodology for appraising carbon sequestration potential was introduced, containing (1) introducing the conceptual model, (2) developing the mathematical model, (3) obtaining the wellbore-pressure solution, (4) determining the injection time, and (5) appraising the carbon sequestration capacity. In the conceptual model, the shale formation were divided into two subsystems and three regions, including matrix subsystem, natural-fracture subsystems, hydraulic-fracture region, inner region, and outer region. With basic equations, a mathematical model was developed in those subsystems and regions. Then, based on the mathematical model, CO2 storage potential in abandoned shales was investigated at different values of fracture conductivity, fracture number, fracture length, inner permeability, and wellbore length. This meaningful work provides a guideline to select wells and monitoring facilities for storing CO2 in residual depleted shale reservoirs.

AAPG Datapages/Search and Discovery Article #90267 ©2016 AAPG/SPE Africa Energy and Technology Conference, Nairobi City, Kenya, December 5-7, 2016