Sustainable Production from Shale Gas Resources through Heat-Assisted Depletion

Abstract

Advancements in drilling and production technologies have made exploiting resources, which for long time were labeled unproducible such as shales, as economically feasible. In particular, lateral drilling coupled with hydraulic fracturing has created means for hydrocarbons to be transported from the shale matrix through the stimulated network of microcracks, natural fractures, and hydraulic fractures to the wellbore. Because of the degree of confinement, the ultimate recovery is just a small fraction of the total hydrocarbons in place. Our aim was to investigate how augmented pressure gradient through hydraulic fracturing when coupled with another derive mechanism such as heating can improve the overall recovery for more sustainable exploitation of unconventional resources. Knowledge on how hydrocarbons are stored and transported within the shale matrix is uncertain. Shale matrix, which consists of organic and inorganic constituents, have pore sizes of few nanometers, a degree of confinement at which our typical reservoir engineering models break down. These intricacies hinder any thorough investigations of hydrocarbon production from shale matrix under the influence of pressure and thermal gradients. Kerogen, which represents the solid part of the organic materials in shales, serves as form of nanoporous media, where hydrocarbons are stored and then expelled after shale stimulation procedure. In this work, a computational representation of a kerogen–hydrocarbon system was replicated to study the depletion process under coupled mechanisms of pressure and temperature. The extent of production enhancement because of increasing temperature was shown. Moreover, heating requirements to achieve the enhancement at reservoir scale was also presented to assess the sustainability of the proposed method.

Enhanced Recovery From Organic-Rich Shales through Carbon Dioxide Injection: Molecular-Level Investigation

“…The high-temperature case was considered to outline the impact of CO 2 injection at a temperature higher than that of the reservoir. The heating source could be a renewable one such as solar panels creating an integrated sustainable energy system. − The adsorption profiles of pure CH 4 at both temperatures are similar. Nevertheless, the adsorption magnitude of CH 4 when CO 2 exists in the mixture is different.…”

“…The pore size distribution revealed a predominance of pore sizes between 0.2 and 0.3 nm (in radius), with a few larger ones alluding to the capability of sorption sites to host single molecules, a characteristic of the Langmuir-like adsorption behavior (Figure ). − …”

Effect of Kerogen Thermal Maturity on Methane Adsorption Capacity: A Molecular Modeling Approach

“…Then, successive molecular dynamics stages of initialization using three-dimensional periodic boundary, 9.5 cutoff distance and 2.0 skin (isochoric-isothermal NVT and isobaric-isothermal NPT) were performed on the initial cell using LAMMPS, following a systematic temperature reduction to the assigned level (i.e., NVT for 250 ps, two NPT stages for 200 ps followed by two other NPT stages for 400 ps). This annealing approach ensured system stability during convergence [ 40 , 41 ]. The protocol followed in the creation of the nanostructures is given in Figure 2 .…”

Reserves Estimation for Coalbed Methane Reservoirs: A Review

“…There are some challenges associated with this technique, such as that (i) a robust microwave radiation antenna is needed, (ii) time and frequency are prerequisite parameters that must be known, and (iii) the range of microwave heating needs to be known. The subsurface heating element can be placed to increase the reservoir temperature, increasing desorption rate, reducing the condensation rate, and minimizing the molecular fractionation effect [47,48]. The rate of methane desorption can be enhanced further through coupling carbon dioxide injection with heating [49].…”