Modern Oil Spill Modelling Tools: A Panacea to Slow and Ineffective Response in Nigeria.
Over the last couple of weeks, the media (print and electronic) has been awash with the grounding of the cargo ship MV Wakashio in the southeast of Mauritius in the Indian Ocean. This cargo has released an estimated 1,000 tonnes of low sulphur fuel oil. The incident has drawn global condemnation because it took place near two environmentally protected marine ecosystem and the Blue Bay Marine Park Reserve, a wetland of international importance. Just like any other spill incident, such spill was never envisaged and as a result resource, manpower and equipment mobilization was a huge challenge. According to Amah Onyedikachi, humans have reached a point of technological advancement that is both fascinating and comfortable, however, not all of that is enough to take away the fact that we need the environment for survival.
As far back as 1971, Scientists have predicted that oil spill would become a major environmental disaster. Over the years oil spills have occurred in different parts of the world including the Puerto Rican oil spill (1971), Exxon Valdez (1989), the Persian Gulf War (1991), Bodo Oil Spill (2008) and the Macondo Oil Spill (2010) and the list can go on. These spills have devastating — environmental, health, social and economic impacts on humans, plants, animals and — the entire ecosystem. For instance, British Petroleum (BP) is estimated to have spent an estimated $65 billion in clean-up and compensation in the aftermath of the Macondo disaster.
In a bid to protect sensitive environmental receptors, reduce the environmental impact of an oil spill, determine the impact area in order to ensure that optimum response operations are carried out, oil spill modelling tools were born. These models have found wide applicability in response, planning, drills and exercise, oil spill contingency planning (OSCP) as well as in training.
OIL SPILL IN NIGERIA
According to Amnesty International, the Niger Delta mangrove is one of the richest in the world, yet it is among the most polluted places on earth. Although there are laws to check oil spill, about 40 million litres of oil is spilt into the environment across different locations in Nigeria especially the Niger Delta and the Gulf of Guinea (GOG).
Nigeria has a long history of oil spills. Between 1976–2014, 12,000 oil spill incidents were recorded. According to the 2018 Nigerian Oil and Gas Industry Report by the Department of Petroleum Resources, 9718.22 barrels of oil was spilt from 569 reported incidents. On the other hand, the National Oil Spill Detection Response Agency (NOSDRA) saddled with the responsibility of coordinating and implementing the National Oil Spill Contingency Plan (NOSCP) reported a total of 13,091 spill incidents with a total oil release of 692.761 barrels from 2006-March 2020.
The exact amount of oil spilt into the environment in Nigeria has always been a subject of controversy between government, International Oil Companies (IOCs) and civil society organisations. This is due to the absence of a centralised oil spill data collation and organisation agency in Nigeria. As such, there is a wide discrepancy in the report from the different organisations. Therefore, any spill data should be taken with scepticism.
Oil spill is a prevailing problem in Nigeria because of decaying infrastructures. About 50% of spilt oil is caused by pipeline corrosion and tanker accidents. Years of neglect by government and IOCs in oil-producing communities has led to inequality and social injustice, thus, increasing the rate of pipeline interdiction and exacerbating the oil spill crisis in the Niger Delta region. Another important factor is the lack of political will from stakeholders in the oil and gas industry to put an end to this menace. Laws exist but implementation has not been effective because oil sales are the main source of government revenue. For example, 80% of the oil produced in Nigeria is from Joint Venture (JV) and Production Sharing Agreements (PSA) producing fields (55% JV and 35% PSA). This means that the Nigerian government is part and parcel of oil spill problem. The only way to enforce compliance would be to punish offenders and force companies to clean up spill sites as soon as spillage occurs. Many observers, including this writer, wonders whether this will ever happen anytime soon. I wish the reverse is the case and I am proven wrong. But what difference can oil spill modelling tools make in addressing this menace?
WHAT ARE OIL SPILL MODELLING TOOLS?
Worried by the amount of oil spilt into the environment and the cost implications, different modelling tools have been developed by various organizations, companies, and researchers to help responders and emergency workers to mitigate or reduce the impacts of oil spills in the environment. Oil spill modelling provides a forecast of oil trajectory (direction of travel) and fate (how the oil will behave) based on known or estimated oil properties and local prevailing conditions. These models can range from simple vector calculation to sophisticated computer models that depend on key oil parameters such as the type and quantity of oil spilt, location of the spill, rate of release and the and the timing, especially in relation to the season. Key environmental input data include wind strength and direction, ocean currents, tides and air and sea temperatures. Other key factors are the biological composition of the affected environment, the ecological importance of the component species and their sensitivity to oil pollution. These models were developed with different features to suit different purposes due to variability in environmental and hydrodynamic conditions, applicability to location and ease of use. However, they have the same structure (fig 1).
There are two broad categories of models for oil spill response. The first category is the oil weathering models that predict how oil properties will change over time (evaporation, spreading, dissolution, emulsification, stranding, dispersion, fragmentation and biodegradation) when spilt into the environment, but does not predict the potential direction of travel of the oil slick. The second category of models is the trajectory model that predicts the direction of travel of oil as well as the weathering profiles. It is important to note that, even though trajectory models predict the weathering profiles of oil slick, they are however limited. Hence, the use of trajectory models alongside other weathering models to make up for the shortcomings.
These models have undergone evolution overtime to capture some key important processes that had hitherto been ignored in the earlier first and second-generation models. Typical examples of some of these models include; the NOAA General Operational Modelling Environment (GNOME), EUROSPILL, OILMAP (Oil Spill Model and Response System), SINTEF, OSCAR, OSIS and ADIOS (Automated Data Inquiry for Oil Spills) etc. The choice of which model to use is dependent on whether it is a response or contingency planning operation, the oil spill location, availability of data, and the questions raised by the end-user. These computer models have proven to be efficient in simulating the movement, spreading and weathering of spilt oil, and has been used in hindcast and forecast mode.
Despite all of these, it is imperative to state that just like other mathematical models, oil spill models have their own limitations and are no substitute for real-time observations. These models are only capable of making predictive estimates of fate and trajectory, and the quality of the input data will influence the quality of the model output. Users of the modelling data should understand the model limitations and the inherent difficulties in predicting oil fate processes (e.g. evaporation, emulsification, etc.). For instance, most of these models are geographic and area-specific and may not find application in other parts of the world. However, GNOME and ADIOS2 have found wide applicability globally. In addition, they have limited backtracking mode and 3D hydrodynamic fields. Furthermore, most of these models were developed using data from microscale laboratory experiments, hence, there is a lot of mathematical approximations that are carried and that affects the reliability of the models. Finally, the use of these models during an emergency situation is challenging because of the lack of availability of data. This implies that relying on oil spills models 100% is dangerous and should be complemented with drills and exercises.
HOW CAN THESE MODELS HELP IN SWIFT AND EFFECTIVE RESPONSE IN NIGERIA?
Oil spill in Nigeria especially in the Niger Delta is an environmental disaster that requires adequate attention by IOCs, indigenous operators, government and the international community. To produce an effective and result-oriented oil spill plan, the possible trajectory of spilt oil, as well as the chemical and physical changes it will undergo under different environmental hydrodynamic conditions, must be modelled, understood and analysed. This is because, in the event of an accidental oil spill, responders and managers are under immense pressure to ensure prompt and adequate clean-up of the oils in order to protect the coastline and sensitive environmental receptors. Therefore, the availability and use of these decision support systems will ensure that the E&P companies, National Oil Spill Detection Response Agency (NOSDRA), Clean Nigeria Associates (CAN) and other agencies saddled with the responsibility of oil spills respond appropriately and within the shortest time possible. These models have become so sophisticated that they have been designed to cater for oil spills in the marine environment, land and surface water (simulating oil and chemical releases from pipelines, rail corridors, storage facilities and other land-based locations), subsurface release as well as the behaviour of spilt oil in the atmosphere. Therefore, combating oil spills from different sources in Nigeria is now made a lot easier with such tools. For instance, most of the IOCs operating offshore use OILMAP, OSCAR and other modelling tools as part of their spill activation plan, exercise and training. There is, therefore, a need to encourage and enforce the use of land-based (pipelines, storage facilities etc) oil spill modelling tools to checkmate oil spills on land, shallow waters and swamps of the Niger Delta.
It is imperative to state that, despite producing crude oil for more than five decades, Nigeria does not have a state-of-the-art oil spill modelling tool dedicated to the oil and gas and maritime industry. Therefore, efforts must be made to develop a modern oil spill modelling tool for the country considering the limitation associated with some of these models (they are geographically specific).
CONCLUSION
Oil spill is a global concern, and there is still a huge challenge in controlling it as well as how to effectively clean it up in Nigeria. However, modern oil spill modelling tools have come in handy in assisting oil production companies and oil spill responders to model spill in advance of their occurrence. Thus, in the event of a spill, clean-up is completed quickly and efficiently.
The government has to commit to ensuring and enforcing adequate oil spill clean-up laws in Nigeria. This includes proper clean-up of oil spills, restoration of the environment close to its natural state, treatment of waste before its disposal into the environment.
The Earth will not continue to offer its harvest, except with faithful stewardship. We have to protect and preserve it at all cost.
REFERENCES
Chinedu, E. and Chukwuemeka, C. (2018) “Oil Spillage And Heavy Metals Toxicity Risk In The Niger Delta, Nigeria”. Journal Of Health And Pollution 8 (19), 180905
Oil Spill Modelling (2018) available from <https://www.itopf.org/knowledge-resources/documents-guides/fate-of-oil-spills/oil-spill-modelling/> [15 October 2020]
Ordinioha, B. and Brisibe, S. (2013) “The Human Health Implications Of Crude Oil Spills In The Niger Delta, Nigeria: An Interpretation Of Published Studies”. Nigerian Medical Journal 54 (1), 10
Watts, M. and Zalik, A. (2020) “Consistently Unreliable: Oil Spill Data And Transparency Discourse”. The Extractive Industries And Society 7 (3), 790–795
Zafirakou, A. (2018) “Oil Spill Dispersion Forecasting Models”. Intechopen [online] Available from <https://www.intechopen.com/> [15 October 2020]
