Cairn Energy PLC
Corporate Responsibility Report 2009
Corporate Responsibility Report 2009
- Environmental Impact Assessments
- Air emissions
- Energy use
- Waste
- Water and resource use
- Spills
- Biodiversity
- Environmental compliance
- Data
Water and resource use
Cairn recognises that water consumption is an important issue, especially where local access to clean water is a challenge, so we continually monitor our water consumption across all our activities. We are also determined to discharge all water used during our operations in a safe and responsible manner.
Water Consumption
In 2009, we have updated the indicators for water consumption in line with indicator EN8 of the GRI G3 Guidelines (Total water withdrawal by source). Consumption figures for 2006–2008 are, therefore, not directly comparable as the data was collected for potable and non-potable water consumed rather than fresh water and brackish water.
In Rajasthan, our operations are particularly focused on water consumption as access to water in this region is very scarce. We have reported on our activities regarding how we have provided for local communities in the construction of rain-harvesting structures and the sharing of data with the local water authorities to improve knowledge of groundwater sources in the region. Operationally, we have looked to minimise our water requirements by hydro-testing sections of our pipeline.
Discharges to Water
In 2009, across all of our production operations, there has been a reduction from previous years in oil discharged in water effluent.
At our production facility at Sangu in Bangladesh, currently operating under special dispensation, our effluent management solutions (see case study below) have avoided the need to dilute effluent in order to meet regulatory discharge limits. In 2009, the quality of water discharged at Sangu averaged 25mg of hydrocarbon per litre of water discharged.
Water re-injection at Sangu
Cairn's Sangu Field in Bangladesh has been producing natural gas since 1998. The gas is transferred from the offshore platform to the onshore plant by a sub-sea gas pipeline and processed to remove hydrocarbon condensate, water and other contaminants. The majority of free water is separated in the offshore platform and re-injected into the gas reservoir via a non-producing well.
After a successful pilot study in 2008 into the feasibility and effectiveness of re-injecting produced water into non-producing wells, we have continued produced water re-injection at the Sangu-5 well during 2009. We re-injected a total of 27,300 bbls of liquid into the offshore wells, which is equivalent to 22% of total liquid production.
We stopped produced water re-injection to Sangu-5 on 16 February 2010, due to an increase in wellhead back pressure but plan to restart produced water re-injection in the Sangu-4 well after a well intervention programme in March 2010 and continue re-injection for the duration of the field's life.
Water re-injection significantly reduces the total quantity of water treated onshore and subsequently discharged into the Bay of Bengal. The average volume of produced water discharge without re-injection was around 371 bbls a day but from April 2010, this will reduce to 175 bbls a day.
Resource Use
The major resources that we use are gas and diesel for energy generation. These are reported on in the Energy section.