Seemant Rajput

Objectives of this study is to present a systematic workflow for geologic hydrogen exploration. The workflow is designed by considering, the characteristics of hydrogen play elements such as source, generation, migration, accumulation, and seal. Methods This study reviewed geologic hydrogen seepages found globally in Africa, Australia, Brazil, Europe, and USA and a discovery in the Bourabougou in Mali. This established that geologic hydrogen could generate, migrate, and accumulate in subsurface reservoirs analogous to hydrocarbon plays. However, distinct difference in geologic hydrogen play is its source rock (Fe-rich, radioactive hard rocks), geological conditions and physicochemical reactions based on this a detailed workflow developed and presented to explore geologic hydrogen, with following broad steps: 1. Hydrogen geology 2. Hydrogen subsurface modelling 3. Hydrogen prospecting Results, Observations, Conclusions Geologic hydrogen generation mechanism established by various studies and lab experiment included serpentinization and radiolysis other process like pyrolysis of organic matter and deep mantle de-gassing also suggested by few authors. This study focuses on serpentinization and radiolysis which are related to water rock reactions. The main outcome of this study is a stepwise workflow, 1. Hydrogen geology study which is the first step details out integration of available maps of surface lithology, mineral, ore and mining location, topography, structural and tectonics, gravity & magnetics data, and natural seepages in the area, if any. This integration delineates selected area for field survey and produce pre-field maps for outcrop geological investigation. Outcrop study produced protocols of rock, water and gas sample collection and gas measurements. Lab analyses workflows establish protocols for Rock, water, and gas analyses such as petrography, XRD, XRF, GC, stable isotopic analyses 2. Hydrogen subsurface modelling produced a workflow for geochemical modelling which uses mineralogical composition, water composition P/T condition to generate equilibrium batch and kinetic models. Reactive transport model entails earth model, porosity/permeability, and flow simulation. Reservoir modelling for reservoir properties modeling if accumulation is in porous reservoirs and fracture modeling in induced porosity. 3. Hydrogen prospecting elaborates hydrogen seepage detection of GSDs (Fairy circle) using remote sensing and AI-ML tools followed by hydrogen surface monitoring using handheld hydrogen sensors. Multiphysics data study like CSEM, gravity and magnetic integration with seismic which generates area of interest (AOIs) to test the site with R&D drilling and hydrogen measurements to establish the play presence. Prospect maturation workflow provides steps to derisk reservoir, trap, and seal and generated leads and prospect for exploratory drilling. Novel/Additive Information This workflow produces a multidisciplinary approach to discover geologic hydrogen play elements, source rock geochemistry of Fe rich rocks, multi-physics data applicability, automated GSDs interpretation using AI-ML, lab based and modeled quantification of geochemical potential of hydrogen.

Co-auteur : Ernest A Jones, Hongwen Zhao, Hasnol Hady Ismail, Seng Wah Tan, Junxiao Li and M Izzuljad B Ahmad Fuad