The petroleum industry must satisfy energy demand while safeguarding the environment as global interest in sustainability rises and more zero discharge regimes emerge. Operational discharges from offshore vessels and structures cause untold damage to ecosystems but rarely make news headlines as these acts are mostly perpetuated in the open sea, at night and impacts are less visible due to advection. Oil spill response is complex, expensive and long-lasting. Chemical releases are more difficult to clean and the environment is seldom completely restored, making prevention more desirable. This paper was informed by this scenario and identified gaps in the literature, which mostly reports accidental spills. The nature, sources, causes and effects of operational discharges are highlighted; existing preventive and remediation measures are critically evaluated, and the imperatives of recent regulatory changes for process safety are examined. Live cases are cited from across the globe to assess typical solutions and/or penalties deployed. Relevant local, regional and international regulations are juxtaposed with developments in design, operating procedures and asset integrity measures for selected case studies. Since the ratification of MARPOL 73/78 by certain countries, subsequent decades have seen the continual operation of tankers without segregated ballast tanks, double hulls and other spill prevention design features at major oil loading and unloading hubs across the Gulf of Guinea. Several discharges go unreported and the penalties are barely enforced by regulators. Taking a cue from mature zero discharge regimes such as Norway, discharge prevention measures would be economically viable, address environmental considerations and enhance the corporate image of operators. In a comparative analysis of the value of energy production, social and environmental concerns often indicate great disparity. Creating a good balance on the economic scale will possibly show a different and more realistic perspective on the cost of production. This paper advocates a proactive and preventative, rather than the reactive and curative approach typical of most previous studies. Implementation of recommended engineering and administrative controls are hoped to aid the industry's drives towards zero harm, self-regulation and social license-to-operate in a world apprehensive about oil and gas. They will strengthen regulators in developing economies with heavy dependence on hydrocarbons and poor enforcement, where operators often overlook regulations.

The global economy has increased CCUS technology development programmes to attain its commercial deployment, which is expected to be beneficial for developing countries such as Nigeria. This paper aims to examine the barriers to CCUS implementation in Nigeria by investigating the differences between global CCUS and Nigerian status, evaluating the perspectives of industry and government practitioners on the economic barriers to CCUS implementation, and identifying policy and industry strategies to deepen the adoption of CCUS. Study participants were selected using a purposive sampling technique to explore the opinions of personnel working in three oil-related agencies: Nigerian National Petroleum Corporation, Ministry of Petroleum Resources and Nigerian Liquefied Natural Gas. Information collected from existing literature and related reports on CCUS were critically analysed, whereas data from semi-structured interviews were generated by audio-recording of participants’ responses. These responses were transcribed from audio recordings for each participant and quality controlled by ensuring that transcripts matched the respective responses. Transcripts were analysed using thematic analysis, exploring the research theme using both theory and practice. The theoretical framework utilised PESTEL and SWOT analyses to evaluate the macro environment and the internal and external environment of CCUS implementation in Nigeria. PESTEL analysis showed that CCUS implementation in Nigeria is driven by various regulatory and policy frameworks, lack of adequate capital, public acceptance and infrastructure. Similarly, the SWOT analysis showed that Nigeria has enough coal reserves that could serve as a potential for CCUS implementation. However, Nigeria’s weaknesses include lack of expertise in CCUS technology, inadequate capital for CCUS investment and policy summersaults by successive governments. Nigeria should thus consider the introduction of subsidies to mitigate various barriers and challenges that hinder CCUS implementation, e.g., low tax rate for enterprises involved in CCUS implementation. There is also urgent need to improve funding of CCUS implementation through foreign direct investment or by the equity market. Furthermore, the importance for an enhanced technology to deepen the adoption of CCUS in Nigeria can not be overemphasized as the world moves towards decarbonisation and Net Zero.

The demand for crude oil and petroleum products have subsequently led to an increase in the likelihood of occurrence of oil spills. It is therefore imperative to understand the impacts of these spills on humans and the environment. Developing appropriate oil spill response and remediation techniques can be achieved by understanding the fate and likely trajectory of different types of oils, once they come in contact with the sea surface. Though still at the nascent stage of oil and gas exploration, the Sierra Leone basin is known to hold large undeveloped hydrocarbon reserves which are being exploited with the aim of contributing to national development. With the availability of oil spill modelling tools, and owing to the fact that environmental conditions vary over time, there is the need to carry out routine studies on the likely behavior of a spill offshore Sierra Leone. This study aims to develop a prediction model that would aid in understanding the fate, trajectory and uncertainties of oil spilled on Sierra Leone waters in the dry, rainy, and harmattan seasons. In order to analyze the trajectory of a spill in the Sierra Leone basin, the GNOME software was used. Furthermore, ADIOS2 was also employed to analyze the weathering processes of the spill. The results obtained from GNOME showed that during the dry and rainy seasons, approximately 15% of oil would be stranded on the shores of Sierra Leone, within three – five days. Owing to the permanently warm water temperatures in the Gulf of Guinea basin, a high percentage of the oil is expected to evaporate and disperse within few days of the spill. The weathering models from ADIOS2 reveal that 34% of oil would be lost to evaporation in the dry season, and 36% and 38% will be lost in the rainy and harmattan seasons respectively. Furthermore, it can be seen that dispersion accounts for 2.5% of oil lost in the dry season, 7.8% during the rainy season and 6.2% in the harmattan period. Within 5-days, ADIOS2 reveals a stable water-in-oil emulsion, leading to an increase in viscosity and density. Airborne benzene concentration is expected to be high on the first day of the spill, but would decrease as the days go by. Based on these results, it is recommended that oil spill response personnel are professionally trained, and equipment must be available to respond to spills in a timely and efficient manner.

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