Adnoc has put increased emphasis on the development and utilisation of natural gas resources, both onshore and offshore, to meet the growing demand for power generation, water desalination, petrochemical plants, and for gas injection to enhance condensate and oil production.

However, top priority has also been given to recovering and processing the associated gas to avoid flaring, targeting the zero flaring concept.

Onshore fields

Development in the onshore fields has taken place over the past three decades.

The commissioning of the Onshore Gas Development project (OGD-I) started in February 1996. The objective of the project is to increase the capacity of the existing gas processing plant at Habshan to 1.8 billion cu ft per day of natural gas, and to increase condensate recovery to 130,000 barrels per day (bpd) and natural gas liquids (NGLs) to 5,900 tonnes per day (tpd).

OGD-I project facilities consist of two new trains, each having a capacity of 350 million cu ft per day, to process the combined streams of Bab Thamama ''B'' associated gas and Thamama ''C'' non- associated gas.

In addition, OGD-I project facilities include one new train for processing non-associated gas from Bab Thamama ''F'' reservoir with a capacity of 610 million cu ft per day. Thamama ''F'' reservoir also includes new compression facilities with 830 million cu ft per day, to recycle the lean gas into Thamama ''F'' reservoir.

The Thamama ''C'' & ''F'' gas gathering/injection network project, which was executed as an integral part of the OGD-I project, was completed in early 1996.

The project consists of two main networks, the Thamama ''F'' & ''C'' gathering network for the transfer of produced gas to the processing plant and the gas injection network which carries lean gas, after extraction of its condensate and NGL, into the compression plant for injection into the Thamama ''F'' reservoir for pressure maintenance through 18 gas injectors.

The project also included the installation of remote manifold stations, sweet gas distribution and electrical supply systems.

The Asab Gas Development (AGD) project was completed and commissioned in April 2000. The project's design capacity is 830 million cu ft per day of natural gas and about 90,000 bpd of condensate. The separated and dehydrated gas is recycled into Thamama ''F'' and ''G'' reservoirs.

The AGD project comprises the drilling of 40 gas producers and gas injectors in addition to gas pipelines and processing facilities for condensate recovery as well as a compression station to recycle the dried gas back into Thamama ''F'' and ''G'' reservoirs. The produced condensate is pumped through a new condensate line to Ruwais Refinery.

The construction of OGD phase II (OGD-II) was completed and commissioned in April last year. The project's objective is to produce about one billion cu ft per day of dry sweet gas in addition to 45,000 bpd of condensate from Bab Thamama ''C'', units 6 &7 and Thamama ''D'' reservoirs.

The project comprises the drilling of 51 gas producers and the installation of a new gas processing plant within the existing OGD-I premises.

The produced dry and sweet gas supplies Adnoc's gas pipeline network. The condensate is pumped to Ruwais refinery.

Projects which are currently under the implementation phase are as follows:

Onshore Gas Development Project Phase-III (OGD- III)

This project consists of the expansion of Bab Thamama ''F'' to produce an additional 1.2 billion cu ft per day of Thamama ''F'' gas and gas reinjection facilities for recycling gas to Thamama ''F'' reservoir.

The additional condensate production will be in the region of 140,000 bpd.

The expected completion date is early 2007.

Asab Gas Development Phase-II (AGD-II)

This project consists of the expansion of Adnoc's Asab Gas Plant for sweetening and NGL recovery to process a further 800 million cu ft per day of gas.

The expected completion date is early 2007.

Offshore fields

As the case in the onshore fields, the development process and gas production enhancement has continued in the offshore fields.

The offshore Abu Al Bukhoosh Khuff Gas Development and Umm Shaif Gas development projects to supply Adgas with additional gas for its third LNG train, were fully commissioned in 1992 and 1994 respectively.

The Zirku Gas Project facilities, which have been designed to recover around 70 million cu ft per day at Zirku Island and export it to Das Island, were commissioned in 1996. Besides avoiding gas flaring and increasing revenues, the purpose of this project was to improve Upper Zakum oil specifications.

The Gas Recovery Compressor Project facilities in Abu Al Bukhoosh field were commissioned in 1996.

This project has substantially reduced emissions to air and has helped to recover around 130 million cu ft per day of associated gas. The recovered gas is utilised in gas lift operations and for oil reservoir pressure support.

The ongoing Offshore Khuff Gas Development (OKGD) project will increase gas export from the Abu Al Bukhoosh Khuff field to 540 million cu ft per day.

It is expected to be completed by the year 2003.

Gas processing

Adnoc has responded through its subsidiaries to the world trend in the gas sector through greater investment commitment in offshore and onshore gas projects.

Of recent interest is the LPG train project currently under detailed engineering in Adgas. The premise of this project is to give Adgas further capacity to capture residual market opportunities.

The project aims at increasing the FEED supply to Adgas by 25 per cent, i e 1.22 billion cu ft per day and producing an additional one million tonnes per year (tpy) of LPG.

The LPG project has an environmental dimension. It will introduce additional freedom in operations. Consequently, the increased production flexibility will help mitigate flaring activities and contribute to zero flaring goals. The slated time of completion for the LPG project is in the third quarter of 2005.

Another bold move in the gas sector is the proposed tie-up of the offshore and onshore facilities.

This is embodied in a project that will export gas from Umm Shaif Super complex (offshore) to Habshan Gas Hub (onshore). The pipeline is expected to carry approximately 500 million cu ft per day and will commence this year.

Adnoc, through its subsidiary Gasco, completed the Abu Dhabi to Jebel Ali gas line project in May last year. This line supplies Dubai with 500 million cu ft per day.

With such large-scale projects, an inherent responsibility rears itself, and it is that of the environment.

To this end, Adgas, as a subsidiary of Adnoc, has embarked on installing a sulphur recovery plant of 99 per cent yield.

This is in anticipation of stricter environmental codes and to further reduce the footprint left on the offshore environment, according to Adnoc.

Further to that another nuance in the Adgas emissions has been addressed through the Boil-Off Gas Compressor Project.

The main role of this compressor is to counteract the gas that is released when loading and unloading the LNG fleet vessels at Das Island.

Another step in the right direction in the gas sector has been to continually undergo self-assessments through peer reviews and various benchmarking exercises.

This is evident in Adgas' plant integrity, reliability and recertification project, which evaluated the LNG plant condition on Das Island and recommended countermeasure schemes.

Similarly Gasco has a series of schemes that are designed to counteract the general ageing of the gas plants.