Title : Immature organic-rich shales: Hot water treatment big-scale experimental study
Abstract:
Organic-rich shales are some of the most complex hydrocarbon resources to exploit due to their low permeability, intricate geological structures, and high kerogen content. With the global focus increasingly directed toward reducing carbon emissions, a critical question emerges: is developing these challenging resources still worthwhile given their environmental footprint and extraction difficulties? One promising solution might be thermal hot water treatment, which presents a more sustainable alternative for extracting hydrocarbons from unconventional resources like organic-rich shales. As hydrocarbons remain essential not only as fuel but also as a vital input for various materials, it becomes essential to explore more sustainable extraction approaches. This research introduces a large-scale laboratory experiment designed to test the potential of thermal treatment for extracting hydrocarbons from organic-rich shales. The experiment models the application of hot water treatment within a high-stimulated reservoir volume (SRV) area between two wells, replicating a field environment. This method could represent a cleaner approach to shale resource development. The study used 18 kg of kerogen-rich core samples – both in large, consolidated form and crushed – and subjected them to subcritical and supercritical water treatments at 300°C, 350°C, and 380°C in a high-pressure combustion tube device. This process yielded 1.5 kg of hydrocarbons, with each stage thoroughly analyzed through material balances to evaluate the extent of organic matter conversion. Remarkably, 98% of the organic content in the samples was converted and recovered, even from the core's central portions. A range of advanced analytical techniques – Including pyrolysis, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), computed tomography (CT), and X-ray fluorescence (XRF) – was employed to assess both the extracted hydrocarbons and the treated rock. These analyses uncovered key relationships between thermal treatment parameters and changes in rock structure, providing insights into conditions that promote hydrocarbon release. This experiment offers a new perspective on scaling thermal treatment techniques from controlled lab settings to real-world applications, demonstrating their effectiveness in both fractured and consolidated rock formations. The results provide essential groundwork for designing field pilot tests and confirm the potential of thermal hot water treatment as a more environmentally responsible method for organic-rich shale exploitation. This approach could reshape the economic and environmental viability of organic-rich shale development, aligning it with the needs of a lower-carbon future.
Audience Take away:
- This study demonstrates the high efficiency of thermal treatment using hot water as a highly promising technology for the development of organic-rich shales.
- The findings reveal key mechanisms of fluid flow at elevated temperatures within the ultra-tight rock matrix of oil shales, providing critical insights that can enhance the accuracy and efficiency of reservoir simulations.
- The results obtained from this research have direct applicability in planning field-scale pilot tests, enabling more precise estimations of oil recovery potential from such challenging reservoirs.
- This work provides unique and unprecedented data on hot water treatment, contributing valuable knowledge that was previously unavailable in this domain.
