In Salah Project

The developments taking place in Algeria’s In Salah gas fields are estimated to be costing $2,300 million. The field is being developed by In Salah Gas, a 50:50 joint venture between BP and state energy company Sonatrach, and began operations in mid 2004.

Ultimately, In Salah Gas aims to supply 9 billion m3/year of gas to the southern European market. Gas purchase agreements began to be signed in 1997. The first of these was signed with ENEL of Italy in April 1997, for the supply of 4 billion m3/year to the Italian utility.

Construction of gas infrastructure was carried out by a group of international companies who were awarded contracts for pre-sanction engineering. These included the Japanese/US JGC Corporation/Kellogg Brown & Root (KBR) consortium which was awarded contracts for conceptual and front end engineering and design (FEED) and appointed contractor for all field facilities, and Bechtel of the US which was responsible for infield and export pipelines.

It is estimated that the overall costs of Phase I of the project amounted to around $1.7 billion; this included the development of three gas fields between Golea and In Salah. The entire development now involves 8 core gas fields lying about 745 miles south of Algiers. The first phase was associated with the three most northerly fields that lie closest to the existing Algerian export infrastructure, based on the main gas hub at Hassi R’Mel. The four more southerly fields were developed such that they maintain overall production rates at 9 billion cubic meters over the expected 15 year lifetime of the project. The estimated total reserves are ~7.5 tcf, although further deposits may yet remain to be discovered and tapped. It is expected that most of the gas to be produced will be sweet, with no sulphur and relatively low CO2 levels.

Phase I of the project was completed in 2004. This involved the construction of two pipelines linking Algeria to Europe. A 500km pipeline was constructed to take the processed gas to market, the construction of which lasted from 2001 until August 2003).

Currently, gas produced from the Tegentour and Reg fields is being piped 120km north to a central processing facility at Krechba. In order to meet export gas specifications, CO2 in the produced gas will need to be reduced to a level of no more than 0.3%; depending on the location, CO2 levels can vary between 1-10%, the remainder being almost exclusively pure methane. During the project’s lifetime, the anticipated peak in CO2 production is likely to be ~60 MMscf/d, with an overall total of ~450 bscf. Re-injection of the CO2 from the produced gas stream is expected to result in a net emissions reduction of ~900,000 tpa/CO2. Amine scrubbers are used to remove the CO2, of which approximately 1.4 million cubic metres per day is produced. This CO2 waste gas is then compressed to a very high pressure (so it is in its supercritical phase and behaves as a liquid), and injected into the Krechba Reservoir (a low-permeability sandstone).

After injection, the CO2 is monitored underground. They monitor the migration of CO2 (using geophysical, geochemical and geomechanical techniques). Satellite imagery (InSAR) is used to monitor the entire area, and monitoring inside the wells along with microseismic monitoring takes place.

Since operations began in 2004, the project has successfully captured approximately 1 million tones of CO2 per year (with storage almost as successful, see ‘Issues’ below)

Issues:

• CO2 Compression – the two injection compressors have not performed as well as expected (repairs needed etc.). Since the start-up, 4 million tons of CO2 has been separated, but only 3 million tons has been injected.
• CO2 Sub-surface Movement – there has been some migration of the injected CO2, which has and will continue to be carefully monitored.

BP Magazine (2007) realized that this project is so significant to Algeria ‘that its national oil company (Sonatrach) is now writing a requirement to capture and store CO2 into national policy governing all future gas developments in the country.’



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