Assessment of Shallow Drilling Geohazards for Safe Well Placement from Seismic Data in the Tano Basin, Offshore Ghana

Prosper Aduah  Akaba; Raymond  Dogbevia Eli; Solomon  Senyo Robert Gidigasu; Kwame  Sarkodie; Frederick Kofi Bempong; Cyril Ofori  Kupualor; Jerry Selorm  Greenfields-Dogbevia; Gordon  Foli

doi:10.4314/just.v43i1.1702

Prosper Aduah Akaba KNUST https://orcid.org/0009-0005-1932-6419
Raymond Dogbevia Eli Kwame Nkrumah University of Science and Technology
Solomon Senyo Robert Gidigasu Kwame Nkrumah University of Science and Technology https://orcid.org/0000-0003-4952-7105
Kwame Sarkodie Kwame Nkrumah University of Science and Technology https://orcid.org/0000-0003-4689-4532
Frederick Kofi Bempong University of Ibadan, Nigeria https://orcid.org/0009-0006-9437-9462
Cyril Ofori Kupualor https://orcid.org/0009-0008-0140-5882
Jerry Selorm Greenfields-Dogbevia https://orcid.org/0009-0008-0140-5882
Gordon Foli Kwame Nkrumah University of Science and Technology https://orcid.org/0000-0002-7898-9926

DOI: https://doi.org/10.4314/just.v43i1.1702

Keywords: Geohazards, Offshore Petroleum Exploration, Seismic Data Analysis, Well Placement, Tano Basin

Abstract

The increasing global demand for oil and gas underscores the need for comprehensive assessments of geohazards in offshore drilling operations to ensure safety and efficiency. This study investigates shallow drilling hazards in the Tano Basin, offshore Ghana, focusing on geologic structures and conditions that pose risks to well placement. Utilising high-resolution 3D seismic data, seabed features and subsurface horizons were mapped, and structural depth analyses were performed to evaluate potential drilling risks. The study identified a northwest trending canyon with steep flanks prone to sliding or rotation, posing a risk to wellbore stability. Faults were prevalent in Unit B, with significant gas accumulations associated with an unconformity at Horizon 1. This unconformity serves as a potential trap for gas, elevating the risk of blowouts during drilling activities. Minor gas accumulations were also detected between Horizons 1 and 2, indicating drilling hazards. Key recommendations include avoiding well placements near seabed canyons, fault zones, and areas with gas accumulations. These regions are susceptible to mass movements, explosions, and structural instability, which could compromise drilling operations. The findings emphasise the critical role of seismic data analyses in identifying geohazards and guiding safe and cost-effective drilling strategies. By providing insights into seabed morphology and shallow subsurface geology, this study contributes to mitigating risks and enhancing the safety of offshore petroleum exploration within Tano Basin.

Author Biographies

Prosper Aduah Akaba, KNUST

Dr. Prosper Aduah Akaba is a lecturer with the Department of Geological Engineering, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi-Ghana. He holds a PhD and an MPhil in Geological Engineering from the KNUST. Dr. Akaba has focused his research on energy, environmental geology and earth resources. He has conducted a regional study on the offshore Ghana Margin to understand the basin-filling mechanisms, evolution as well as prospectivity of the sedimentary basins. He has a number of publications to his credit.

Raymond Dogbevia Eli, Kwame Nkrumah University of Science and Technology

Raymond Dogbevia Junior Eli obtained a BSc Geological Engineering degree from the Kwame Nkrumah University of Science and Technology (KNUST). Raymond has gained valuable experience in 3D seismic data interpretation, geological mapping and structural analysis of sedimentary basins from the Springfield Exploration and Production. Currently working as a Field Geologist with West Africa Forage Sarl in Guinea-Conakry, he leads geological sampling programs and utilizes QGIS and MapInfo for data analysis. His technical skill set spans mining industry software (IHS Kingdom, Leapfrog), programming (Python), and data analysis frameworks. Raymond's work combines traditional geological methods with computational approaches, aiming to advance environmental protection and safety standards in extractive industries through data-driven methodologies.

Solomon Senyo Robert Gidigasu, Kwame Nkrumah University of Science and Technology

Solomon S. R. Gidigasu is a Lecturer at the Department of Geological Engineering, Kwame Nkrumah University of Science and Technology (KNUST), Ghana. He holds a BSc, MPhil and PhD degrees in Geological Engineering from KNUST. He was a Teaching Assistant, Demonstrator and Graduate Assistant at the Geological Engineering Department prior to his appointment as Assistant Lecturer. He is an Engineering Geologist and a Geotechnical Engineer. He is a member of the following professional bodies - Ghana Institution of Engineering, Ghana Geotechnical Society and the Ghana Institution of Geoscientist.

Kwame Sarkodie, Kwame Nkrumah University of Science and Technology

Dr. Kwame Sarkodie is committed to the cause of academia with eight-years of teaching and research experience. As a trained oil and gas engineer, his focus is on oil and gas well engineering which spans the areas of drilling, well completions, production, transportation and distribution of hydrocarbons. He also is highly skilled in the area of experimental multiphase flow with a keen interest to develop novel intrusive instrumentation coupled with machine learning techniques for real time characterization of complex flows in conduits and vessels.

Frederick Kofi Bempong, University of Ibadan, Nigeria

Frederick holds a BSc. degree in Geology and an MSc. degree in Petroleum Geoscience, both from the University of Ibadan, Nigeria. He is skilled in field geology mapping, sequence stratigraphy, and unraveling depositional settings. Also, He is excited about engaging in activities that build on his research capabilities, teaching, and learning as well as understanding new frontiers. Frederick hopes to someday leverage his degree and skills to become a renowned researcher in the field of Geosciences.

Jerry Selorm Greenfields-Dogbevia

Mr. Greenfields-Dogbevia is an accomplished and results-driven Petroleum Geoscientist with over 17 years of experience in upstream oil and gas exploration and production. A key architect of major oil discoveries, including Afina, Eban, and Akoma, with a strong track record of increasing the country's oil and gas reserves. Adept at leading multidisciplinary teams, driving strategic initiatives, and contributing to high-level arbitration and exploration projects.

Gordon Foli, Kwame Nkrumah University of Science and Technology

Professor Gordon Foli earned a PhD in Geological Engineering from the department of Geological Engineering, KNUST and an MPhil in Geology from the University of Ghana. He is an experienced Geologist who has about 19 years industry experience before joining academia in 2008. He has research extensively and published in reputable journals in Ghana, Africa and World. His research focus in earth resources and environmental geology and he has 58 publications to his credit and still counting.