EPJ E Highlight - The physics of extracting gas from shale formations

Microscopic model of the shale structure.

A new study outlines the key parameters affecting the production of gas from shale reservoirs, by simulating what is happening at the microscopic scale.

Extracting gas from new sources is vital in order to supplement dwindling conventional supplies. Shale reservoirs host gas trapped in the pores of mudstone, which consists of a mixture of silt mineral particles ranging from 4 to 60 microns in size, and clay elements smaller than 4 microns. Surprisingly, the oil and gas industry still lacks a firm understanding of how the pore space and geological factors affect gas storage and its ability to flow in the shale. In a study published in EPJ E, Natalia Kovalchuk and Constantinos Hadjistassou from the University of Nicosia, Cyprus, review the current state of knowledge regarding flow processes occurring at scales ranging from the nano- to the microscopic during shale gas extraction. This knowledge can help to improve gas recovery and lower shale gas production costs.

Extracting gas from shale has become a popular method in North America and has attracted growing interest in South America and Asia, despite some public opposition. Unlike conventional reservoirs, the pore structures of shale gas reservoirs range from the nanometric to microscopic scale; most natural gas reservoirs display microscopic or larger scale pores.

In this paper, the authors outline the latest insights into how the pore distribution and geometry of the shale matrix affect the mechanics of the gas transport process during extraction. In turn, they present a model based on a microscopic image obtained via scanning electron microscopy to determine how gas pressure and gas speed vary throughout the shale. The model is in agreement with experimental evidence.

The authors reveal that the orientation, density and magnitude of rock bottlenecks can affect the volume and flow in gas production, due to their impact on the distribution of pressure throughout the reservoir. The findings of their numerical simulation match available theoretical evidence.

Click on the images to watch the transient modelling of pressure and velocity distribution for porous illite

Pressure distribution
Velocity distribution
This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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