Contents lists available at ScienceDirect Journal of Natural Gas Science and Engineering journal homepage: www.elsevier.com/locate/jngse Preliminary structural and stratigraphic assessment of an onshore field for CO 2 re-injection in the Niger Delta Basin, Nigeria Bappah. A. Umar a,e,* , Raoof Gholami b , Afroz A. Shah c , Prasanta Nayak d a Department of Applied Geology, Curtin University, Malaysia b Department of Petroleum Engineering, Curtin University, Malaysia c Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE 1410, Brunei Darussalam d Sabah Shell Petroleum Company Ltd., Plaza Shell, Kota Kinabalu, Sabah, Malaysia e National Center for Petroleum Research and Development, A.T.B.U., P.M.B, 0248 Bauchi, Energy Commission of Nigeria, Nigeria ARTICLE INFO Keywords: Stratigraphy Assessment Structures Reservoirs Niger Delta CO 2 re-injection ABSTRACT Detailed preliminary assessment of subsurface is required in potential site for CO 2 re-injection in order to ensure safe and viability of the project. Using 3D seismic data analysis and well correlation, a potential site located onshore Niger Delta Basin was assessed for CO 2 re-injection. The result indicates multiple reservoir units across the stacked stratigraphy, indicating potential multiple CO 2 storage intervals. Well correlation using four wells has further revealed a laterally extensive, thick and sealed potential reservoir located at supercritical depth favorable for geosequestration. Traps are found to be mainly structural consisting of collapsed crest and rollover anticlines. Growth faults are the dominant structural type and the overall structural style within the field is simple with minimal complexity. In the triangle analysis, a potential leak point characterized by thick sand blocks and low potential for shale smearing shows high tendency for CO 2 leakage. However, this would only be the case if injected CO 2 exceeded the maximum supportable column heights which can be obtained using 3D fault seal modeling to further characterized the basin. 1. Introduction Global CO 2 emissions continue to increase because of the increasing demand on energy resources, which mainly utilizes fossil fuel (Global CCS Inst, 2017). This is primarily a direct consequence of growing populations in the world, and particularly in developing nations where more energy is needed to keep pace with various development projects (Global CCS Inst, 2015). Thus the emissions of CO 2 have multiplied, and this will continue in future. And since the CO 2 gas is the most abundant of the released gases, and constitutes about 64% of the enhanced greenhouse effect (Bryant, 1997) therefore more research is required to efficiently store excess CO 2 from the atmosphere. This is highly re- quired because previous studies have categorically shown that in the coming future the concentration of the CO 2 gas in the atmosphere will increase, posing climate change, and global warming threats in the world (Bachu and Stewart, 2002; Bajura, 2001; Global CCS Inst, 2014). Generally, various studies have shown that the emission of greenhouse gasses is the major cause of the current global warming, and its impact on global climate change (Bachu, 2002; Solomon et al., 2014). Even though there have been a lot of effort towards limiting the global temperature rise below 2 °C it is expected that fossil fuels would still account for up to 60% of the world energy requirements by the year 2040 (EIA, 2015). This means there is a serious need to store excess of CO 2 in various reservoirs. We have chosen Niger Delta Basin to test the efficiency of storing of CO 2 gas in geological reservoirs. A large volume of gas (approx. 900 billion cubic feet) is released annually into the atmosphere from the flaring of natural gas in the basin (David and Dosumnu, 2011). Due to its environmental and health effects, there is urgent need to understand the causes of the incessant loss of the gas, and to suggest an efficient way of its storage in the basin. Globally, carbon capture and storage (CCS) is presently considered as the only mitigation option capable of reducing a large quantities of anthropogenic CO 2 gas emission (Global CCS Inst, 2015). And in order to implement the CCS technology in a potential site a preliminary site assessment is needed to characterize the reservoir potentials (CO2RC, 2008) prior to intensive modeling e.g. fault seal analysis before CO 2 storage/re-injection commences. This helps in quick decision making on whether a project should be initiated https://doi.org/10.1016/j.jngse.2019.102919 Received 23 November 2018; Received in revised form 10 April 2019; Accepted 18 June 2019 * Corresponding author. National Centre for Petroleum Research and Development, Abubakar Tafawa Balewa University, Bauchi, Energy Commission of Nigeria, Nigeria. E-mail addresses: bappahau@ncprd.atbu.edu.ng, bappah.adamu@posgrad.curtin.edu.my (B.A. Umar). Journal of Natural Gas Science and Engineering 69 (2019) 102919 Available online 20 June 2019 1875-5100/ © 2019 Published by Elsevier B.V. T