Ballast water

As global trade and traffic volumes have expanded over the last decades, so have the harmful effects these activities have on the marine environment. The problem of invasive species carried by ships from one part of the world to another is a major threat, and at Maersk, we’re working hard to find new solutions to this distressing problem.

Ships carry ballast water to provide stability and adjust trim, stress and torsion for optimal steering and propulsion. However, ballast water often originates from ports and other coastal regions rich in plankton and other marine organisms. Discharging ballast water originating in one marine environment into another can introduce undesired organisms into a marine ecosystem, threatening its ecological balance and acting as a medium for the spread of epidemic diseases.

To ensure proper handling of ballast water, we have ballast water management plans and ballast water logs on all our ships. We also seek to minimise the use of ballast water and to conduct internal and mid-ocean ballast exchange whenever possible.

New IMO regulations
In February 2004, the International Maritime Organization (IMO) adopted the International Convention for the Control and Management of Ships’ Ballast Water and Sediments. This convention aims to prevent the introduction and spreading of aquatic invasive species in areas where they are not found naturally. The IMO convention will introduce treatment standards over the coming years according to the table below. In meantime, ballast water exchange in open sea may be used as a means to limit the effect of invasive species transported in ballast water. From the dates shown below, ballast water exchange will no longer be allowed.

The IMO convention stipulates a set of requirements for the treatment process and “cleaning” of ballast water. The goal of these requirements is to ensure that at least 99.9% of all living organisms in ballast water are removed or killed before the water is discharged.

Developing a sustainable solution
We are also looking into new ways of treating ballast water, and we willingly make our ships available to developers of ballast water treatment systems, so they can test their systems to obtain IMO approval.

Many of the systems available in the market today use potentially toxic chemicals – chloride or ozone. As these options do not accord with our environmental policy, we have initiated a project with two companies to develop a ballast water treatment system that is 100% environment-neutral. In addition to being environmentally friendly, the new system is expected to be less costly to produce and operate, and to take up less space onboard ships.

Discharges to water
At Maersk, we strive to discharge as few substances as possible into the sea. Our policy is that, where discharges are absolutely necessary, we do our utmost to control them. These discharges occur mainly in our energy segment and include discharges of chemicals and produced water, as well as accidental discharges.

Chemicals necessary with present technology
The use of chemicals in the offshore oil and gas industry serves a wide range of purposes, not only in production and maintenance activities but also for environmental and safety reasons. Without the use of chemicals, it simply wouldn’t be possible to drill a well, ensure optimal yield, or protect the facilities against corrosion and bacterial growth. We also use chemicals to separate oil, gas and water to achieve acceptable levels of oil in water for disposal and to pipe oil and gas to shore.

Chemicals discharged during normal operations are subject to a discharge permit and reported to authorities. Prior to any use or discharge, we evaluate the chemicals in accordance with authority guidelines. We assess individual components of a chemical product separately, to determine whether the components might accumulate in living organisms (bioaccumulate), whether they are toxic and whether they are biodegradable. For commercial reasons, manufacturers do not disclose the precise composition chemical compounds to Maersk Oil, but they do provide this information to authorities.

Chemicals discharged at sea (depending on their persistence, bioaccumulation and toxicity) may impact the aquatic ecosystem. Because of this, legislation that governs the chemical discharges is very stringent, and our business units naturally comply with all relevant legislation.

New regulations to reduce discharges
In 2007, the EU implemented REACH, a new set of legal requirements for chemical risk assessment and control of chemical product procurement and use. For offshore applications, a workgroup was established to identify gaps between REACH regulations and the Northeast Atlantic OSPAR Convention (OSPAR regulates the discharges of chemicals into the marine environment in the Northeast Atlantic). The OSPAR Convention has set objectives for the year 2020, by which:

Discharges of oily substances must be reduced to a non-harmful level
Discharges of synthetic hazardous substances must be brought to a near-zero level
Discharges must not affect the background level of naturally occurring substances

In the UK, where many of our oil activities take place, chemical use and discharge is regulated through the Offshore Chemicals Regulations (OCR) 2002, which implement the decisions and recommendations of the OSPAR Convention. OCR 2002 requires that an approved chemical permit is in place before chemicals can be used or discharged during drilling, workovers, production and pipeline operations offshore. These permits describe the selection, deployment, discharge route and environmental impact assessment for both continuous use and ad-hoc chemical products.

In some cases, our business units go beyond what is required by law, and Maersk Drilling is implementing a new global chemical management system that will lead to further improvements in managing chemicals.

Limiting the use of produced water
The simultaneous production of water is an inevitable and unavoidable part of oil and gas exploration and production. As fields mature, we must treat increasing quantities of produced water before discharging it into the sea. Consequently, the total volume of dispersed oil in discharged water might increase, even if the concentration of oil in produced water is reduced or remains constant. Ways to limit or reduce the volume discharged include increasing the volume of produced water re-injected into the reservoirs for pressure support, or injecting produced water into other underground formations. Maersk Oil is investigating the feasibility of such re-injections.

A mixture of water and hydrocarbons is produced from individual wells into the oil, gas, and water separation system. The water is taken from this system to water treatment facilities on our platforms. Here, we separate the produced water from the residual hydrocarbons in a series of separation and water clean-up processes. As previously noted, it is possible to re-inject produced water into the formation in some fields to provide pressure support, while also optimising the production of hydrocarbons. The re-injection of produced water presents a number of technological challenges.

If conditions are suitable for re-injection of produced water, this method can be used to provide pressure support in the formation. If re-injection is not feasible, the produced water is discharged to the sea, after passing through the water treatment system. We treat the produced water to the same standard whether it’s re-injected or discharged to the sea.

Due to the location and structure of oil and gas reservoirs, the production changes over time. After an initial period characterised by relatively high production, the presence of oil and gas in the production stream falls, and the quantity of water increases.

In many fields, it is not feasible to re-inject produced water into the reservoirs to maintain and improve production. In such cases, produced water is cleaned in the water treatment systems at production platforms prior to being discharged into the sea. Water is injected at all our major oil fields (Dan, Gorm, Halfdan, and Skjold) in order to maintain pressure in the reservoir and to sweep the oil towards the producing wells. Most of the injected water is sea water. At the Gorm and Skjold fields, more than 90% of the produced water is re-injected together with seawater. Re-injecting produced water into the producing reservoirs poses a number of challenges, not only in relation to biological activity generating H2S, but also in the creation of scale (i.e. a chemical reaction through which minerals are formed) in the reservoir, in the injection and production wells and in the pipelines. The relative high permeability of the Gorm and Skjold fields (caused by naturally occurring fractures in the formation) reduces the problem of scale and allows re-injection of produced water.

More oil in produced water in mature fields
We monitor all water discharges and measure the concentration of oil in produced water before discharge. Through continuous optimisation of offshore water treatment facilities, we have substantially reduced the concentration of oil in discharged water. As the fields mature, increasing quantities of produced water must be treated before being discharged into the sea. Consequently, the total volume of dispersed oil in discharged water might increase, even if the concentration of oil in produced water is reduced or remains constant. Ways to limit or reduce the volume discharged include increasing the volume of produced water re-injected into the reservoirs for pressure support, or injecting produced water into other underground formations.

The production platforms in the North Sea receive a mixture of oil, gas, and water from the producing wells. Here, we separate the individual components, transport the oil and gas to markets via pipelines, and send the produced water to the water treatment systems, which typically consist of separators, hydro-cyclones, and centrifuges. We reduce the oil in the produced water to the lowest possible concentration before re-injecting or discharging the water. Although we monitor and optimise the cleaning process constantly, a small quantity of residual oil will still remain in the discharged produced water.

From 2004 to 2008, we reduced oil concentrations in produced water by more than 50%.This has resulted in a 40% reduction in the amount of oil being discharged with produced water – despite a 27% increase in the quantity of produced water. The successful reduction of the oil content in produced water is a result of substantial investments in additional water handling capacity and improved treatment methods.

In 2008, the average concentration of oil in the discharged produced water was about 9 mg/litre, equivalent to 0.0009%. As a consequence of improved treatment methods, the total quantity of discharged oil in produced water has fallen notably in the recent years, despite the continuous increase in the quantity of discharged produced water. In the future, however, quantities of produced water are expected to rise further. Unless suitable methods and reservoirs are identified for additional re-injection of the produced water, or new treatment methods are developed, the total quantity of discharged oil contained in produced water will also increase.

Maersk Oil will continue its work to reduce both the concentration of oil in discharged produced water, and the total quantity of oil discharged.

Maersk Oil continually measures oil concentrations in discharged produced water, and we do not exceed the monthly average of 30 mg/l per discharge point. We will continue to investigate and test new technologies for cleaning produced water, as well as further options for further re-injecting produced water underground.

Regulation by the OSPAR convention
In 2007, a new measurement method for concentrations of oil in produced water was introduced at the initiative of the Oslo-Paris Convention (OSPAR). Using the new method, an identical sample of produced water can show 15% greater oil content than if measured using the previous method. As a result, oil concentrations in discharged water have been reduced substantially. In the UK, produced water is treated to meet stringent legislative targets of less than 30 mg/l.

The UK also requires that discharges of produced water comply with OSPAR recommendations. These regulations require Maersk Oil to monitor and report on all produced water discharges. The Produced Water Trading Scheme, which came into effect in January 2007, also sets fixed hydrocarbon discharge allowances that regulate the quantity of oil in produced water discharges. The scheme requires independent verification of OiPW discharges and an annual Produced Water Discharge Report.

The challenges of water re-injection
Whether it is possible to re-inject the produced water depends on a number of factors:

the individual physical properties of the fields
the quantity of produced water
the content of both naturally-occurring components and added components in the injected produced water
the treatment systems available for produced water

Re-injecting produced water also involves a number of complications that need to be considered, including:

reduced recovery of hydrocarbons due to reduced permeability
increased risk of water ingress, i.e. the re-injected water can move towards the producing wells without pushing the hydrocarbons in front of them (if this happens, there is a risk that the hydrocarbon reserves will be bypassed in that section of the formation and will become unrecoverable)
increased quantities of water to be treated on the platforms as a result of more water flowing to the producing wells
increased production of toxic and corrosive hydrogen sulphide as a result of greater bacterial activity, since the produced water contains nutrients that promote the growth of sulphate-reducing bacteria
increased energy consumption offshore due to higher resistance to water injection and higher volumes being processed, leading to additional emissions of CO2, etc.

Limiting oil spills
Although we make every effort to prevent them, accidental spills do happen. Maersk Drilling and Maersk FPSOs had 28 spills in 2008 with a total volume of 122m3. Three major accidental spills occurred in late 2008 on two drilling rigs. These spills account for the major part of the total amount of discharges. Out of the total spillage, 86% consist of seawater spillage from mud pits and thus with a low environmental impact. The objectives for 2008 were to reduce accidental spills by 20% compared to 2007. This target has not been reached due to these three major spills. The graph below shows the different types of spill.

Maersk Oil recorded accidental oil spills of 2.1 tonnes in the Danish sector in 2008.

A formally approved Oil Spill Contingency Plan is in place for each offshore operation, describing procedures in the event of a spill. In general, however, continuous monitoring, adherence to procedures and rehearsal of emergency response plans help our business units keep these unplanned discharges to a minimum.

Discharge prevention on ships
In our transport business, we take comprehensive preventive actions to avoid environmental incidents.

Our crews are trained in safe navigation of ships, our operational procedures are centred on safe ship operation, and we have contingency plans in place to deal with all uncontrolled and emergency situations, including collisions, grounding and spills during bunkering. The Maersk Training Centre conducts a range of courses on environmental matters and safe operation on ships.

In 2008, we required more than 2,700 officers, cadets and shore staff to complete ISO14001 training, and all our seafaring staff participated in e-learning courses on topics such as weather routing and voyage efficiency. Finally, monthly oil spill drills are conducted on all our ships to ensure that the entire crew is up to date on how to deal with oil spills effectively and safely.

In case of an incident, our Casualty Committee (which consists of key staff from different areas of our Group) are called into action. This ensures that measures are taken quickly to minimise environmental and other risks. We have proactively phased out single-hull tankers ahead of MARPOL requirements, and we took delivery of the world’s first double-hull VLCC in 1992. In fact, our entire tanker fleet has been double-hulled since 2002 – even though this is still not a regulatory requirement.

To further reduce the risk of oil spills, we decided that all newly built ships must be equipped with inboard protected fuel tanks. Combined with our phase-out of single-hull tankers, this also helps to minimise the risk of oil spills if an incident should occur.

In 2008, our ships recorded a total of 16 spills totalling 978 litres. Most of these were less than 100 litres, but two did exceed 100 litres – one 400 litres and the other 200 litres. Both spills have been cleaned up.