Managing the Change to OPPC

01 June 2007

When introduced in 2005 the OPPC legislation changed the responsibilities of operating companies with respect to managing produced water and other discharges. The document also laid down a number of new obligations which companies may find difficult to introduce into their working practice. Managing this change and ensuring that the new guidelines are met will be a difficult task, but Andrew Sutton of Katronic outlines technologies that could help to make the transition easier to deal with.

The Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 came into effect at the start of that year. This new legislation has been set out to better monitor and limit the amount of oil and other hydrocarbons discharged in produced water, and replaced the existing documentation concerning sea discharging. OPPC sets schedules for different water applications, and defines what can be considered as produced water, sets limits for oil and hydrocarbon discharges, lists monitoring and reporting requirements and details the possible punishment for companies failing to comply with the new regulations. The three key areas of OPPC are stated as: the need to update the definition of oil, the introduction of a permitting system for oil discharges which allows the recovery of the associated costs via permit fees, and strengthening the powers to inspect and investigate oil discharges – whether these discharges are lawful or unlawful.

According to the monitoring requirements of the legislation, operators discharging greater than two tonnes per annum are required to measure and report dispersed oil content and volumetric discharge on a daily, monthly and annual basis. Furthermore, the new regulations have redefined what is to be considered “oil”. This is now described as “any liquid hydrocarbon or substitute liquid hydrocarbon, including dissolved or dispersed hydrocarbons or substitute hydrocarbons that are not normally found in the liquid phase at standard temperature and pressure, whether obtained from plants or animals, or mineral deposits, or by synthesis”. By broadening the spectrum of liquids to be covered by the oil discharge guidelines, it has become much harder for the platform operators to ensure that they are adhering to the requirements and has created the need for better monitoring and analysis.

As stated above, OPPC will be introduced, monitored and enforced through a discharge permit scheme. These permits will also be used to help fund associated costs. Section three of OPPC is quite specific in defining when a permit is required: “no oil shall be discharged into relevant waters”. The regulations state that no discharge shall take place without the relevant permit in place to cover it. Furthermore, the legislation goes on to state that “an oil discharge permit will therefore be required for the injection, or re-injection, of discharge streams containing oil”. The regulations are very thorough in ensuring that all possible preventable discharges are covered by the new policy.

Permit applications can be obtained through the DTI website at, or in hard copy. Submission of the permit application is preferably done on an e-mail basis, though the DTI does accept that this may not be possible in all cases. The permit applications do not carry a statutory notification for any other governmental body, although the guidelines do state that voluntary consultation would take place under certain circumstances such as “if the discharge will be undertaken close to land, or close to a relevant site as defined in The Offshore Petroleum (Conservation of Habitats) Regulations 2001; or to seek advice from the relevant fisheries agencies”. An application for several discharges can be made and approved under one permit, for example “an installation’s oil discharge permit could include separate schedules for drainage discharges, produced water discharges and periodic discharges such as sand and scale”. For more technical information on permit applications the DTI can be contacted at .

One of the key areas covered by The Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 is the discharge of produced water. As with oil the Department of Trade and Industry have redefined what would be included as produced water. This now reads as “water which is produced during oil, gas or condensate production operations and includes formation water, condensation water, re-produced injection water and water used for desalting oil”. By broadening the definition of produced water the DTI has created a situation where oil operators may be required to install monitoring and metering on systems and pipelines where at present this may not exist.

The Problem:
One of the drawbacks from an operator point of view is that while OPPC is very specific on the limits for oil contact and discharge and provides guidance on the equipment to be used to analyse water samples, it does not indicate how to monitor the total discharge as required by law. On many installations produced water and injection water flowmeters are either missing, out of date, out of calibration or have failed entirely – meaning that establishing reporting systems for volume of daily, monthly and annual discharge could be problematic. According to the DTI guidelines, “Sampling and analysis requirements will depend upon the nature of the permitted operation and will be detailed in the permit schedules. In some cases there will be no sampling or analysis requirements and it will only be necessary to quantify the discharge”. As stated, while chemical analysis of the discharge liquids may not necessarily be required, the operator will always need to be able to produce valid data on the total volumetric discharge of the platform.

The Solution:
In order to provide the required reports on discharge it is essential that the platform has reliable and accurate monitoring of the total produced water discharge, which is where non-invasive ultrasonic flowmeters could be the perfect solution. Rather than incur the cost, lost production and problems associated with carrying out the refit of an existing flowmeter, the clamp-on flowmeters are mounted on the external surface of the pipe ensuring immediate accurate metering of the produced water without any engineering work or shut-down.

A clamp-on flowmeter does not provide the same levels of generic accuracy as may be expected from an insertion or inline device. However, some manufacturers have developed the technology to such a point that the meters can be relied on to give continuous reliable repeatable readings with an uncertainty of less than 5%. Furthermore, as the OPPC 2005 guidelines state that “quantification of discharges, must be measured to +/- 10% uncertainty on volume”, the clamp-on meter should be ideal. The flowmeters can measure and totalise the flow rates and can provide this information to the control system via analogue, digital or serial communications. All the operator has to do is to integrate the flowmeter data with the analytical measurements to ensure that they keep control of their total oil discharge.

The ultrasonic meters are quick and simple to install and are available as a fully ATEX certified solution. Enclosure and transducer types vary from manufacturer to manufacturer, however, given the environmental conditions to which the instruments are subjected, stainless steel sensors and flowmeter enclosures would be recommended. Applications for this technology would vary, though most common usage would be for effluent discharge, produced water, cooling water systems and injection applications.

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