Author ORCID Identifier

https://orcid.org/0009-0008-0887-7014

Semester

Spring

Date of Graduation

2023

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Petroleum and Natural Gas Engineering

Committee Chair

Kashy Aminian

Committee Member

Samuel Ameri

Committee Member

Mohamed El Sgher

Abstract

Abstract

In addition to the gas present in the pores of the rock, shale also contains gas in the adsorbed state within the surface of the organic matter within the formation. As the free gas is produced, the pressure in the reservoir depletes, causing the adsorbed gas to be released, complementing the gas production. At the same time, the pressure reduction leads to increase in the effective stress causing shale compaction. The shale compaction negatively impacts the permeability and hydraulic fracture conductivity. This study aimed to investigate the impact of hydraulic fracture characteristics on the adsorbed gas recovery and, ultimately, on the production from a Marcellus shale horizontal well.

A model for a horizontal Marcellus shale well, completed with multiple hydraulic fracture stages, was employed in this study to investigate the adsorbed gas production from Marcellus shale. The model has been developed based on the available information from several existing Marcellus shale horizontal wells in West Virginia. Laboratory and published data relative to adsorbed gas in Marcellus shale and shale mechanical properties were collected and analyzed. A set of multipliers were generated to account for the impairments in hydraulic fracture conductivity, the reduction in the formation (matrix and fissure) permeability, and the shale shrinkage caused by net stress increase. The geomechanical multipliers then incorporated into the model. The model was then utilized to investigate the impact of different parameters, including Langmuir pressure and volume, fracture half-length, fracture spacing, and fracture conductivity, on adsorbed gas recovery and cumulative gas production. Inclusion of the geomechanical multipliers in the model provided more realistic production predictions and a better understanding of the hydraulic fracture impact. The gas desorption was found to have a higher contribution to the gas production when the reservoir pressure declined sufficiently to allow the gas to be desorbed from the complex shale system. Additionally, The fracture half-length was found to improve the desorbed gas production particularly in the latter stages of the production, while fracture conductivity and fracture spacing improve the gas desorption throughout the production. Therefore, it can be concluded that hydraulic fracturing plays a significant role in the adsorbed gas recovery.

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