Shale Gas Hydraulic Flow Unit Identification Based on SEM-FIB Tomography
Shale gas reservoir developments have steadily increased over the past few years throughout North America. A significant amount of the produced gas in shales is stored in complex submicron pore structures. The absence of an intensive hydraulic flow unit (HFU) model for these shale gas source rocks makes the prediction of economic gas productivity and hydraulic fracturing risky. Therefore, understanding of pore size distribution, permeability, pore connectivity, and other petrophysical properties is crucial for accurate performance prediction and effective reservoir management. This study utilizes the dual-beam (SEM-FIB) instrument for shale gas tomography. The reconstructed 3D sub-micron pore model provides insights into the petrophysical properties of shale gas, including pore size distribution and porosity. These properties were used to define the shale gas hydraulic unit and permeability. The identified flow units were able to fit into existing flow unit models for unconventional reservoirs. The comparison between the proposed method and mercury injection capillary measurements (MICP) revealed similar data range however MICP method tends to slightly overestimate the flow unit. Flow simulation based on 3D Stokes equation using image segmentation was performed and consistent permeability value was found compared to the estimation in SEM-FIB tomography. However, the permeability simulation results tend to underestimate the permeability value in reality. A case example from Utica shale illustrated the use of this approach.
H. Zhang et al., "Shale Gas Hydraulic Flow Unit Identification Based on SEM-FIB Tomography," Proceedings of the SPE Annual Technical Conference and Exhibition: Unconventional Wisdom (2012, San Antonio, TX), vol. 6, pp. 4324-4335, Society of Petroleum Engineers (SPE), Oct 2012.
The definitive version is available at https://doi.org/10.2118/160143-MS
SPE Annual Technical Conference and Exhibition: Unconventional Wisdom (2012: Oct. 8-10, San Antonio, TX)
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
3-D Stokes Equations; Accurate Performance; Dual-Beam; Flow Unit; Gas Productivity; Hydraulic Flow Units; Hydraulic Units; Mercury Injection; Petrophysical Properties; Pore Connectivity; Pore Models; Produced Gas; Shale Gas Reservoirs; Similar Datum; Submicron; Unconventional Reservoirs
International Standard Book Number (ISBN)
Article - Conference proceedings
© 2012 Society of Petroleum Engineers (SPE), All rights reserved.
01 Oct 2012