The first phase
The In Salah Southern Fields (ISSF) project is the second phase of the larger In Salah Gas (ISG) Development Project that first began in November 2001. ISG is one of the largest dry gas projects in Algeria and entails the development of seven proven gas fields in the southern Saharan desert, 1,200 km south of Algiers.
ISG has been producing approximately 8 Bcm/a of gas since July 2004, which is marketed by the joint marketing company In Salah Gas Limited, an association between ISG joint venture partners Sonatrach (35 per cent interest), BP (33.15 per cent interest) and StatoilHydro (31.85 per cent interest).
The first phase of ISG involved the development of three gas fields – Krechba, Teg and Reg – located in the northern part of the In Salah licence. Based on the expected decline of gas production from these three fields, the second phase involves the construction of a 300 km pipeline network.Article continues below…
Starting from scratch – the second phase
ISSF will involve the construction of an over 300 km pipeline network with diameters between 16 and 30 inches. Half of the pipeline will be constructed with stainless steel while the other half will be made of carbon steel. The project will also include construction of a new central processing facility (CPF), a gathering system, and an interfield transfer and expedition line.
The pipeline will transport dry gas from the Hassi Mounene, In Salah, Garat El Beffinat and Gour Mahmoud fields in the central Algerian Sahara to the new CPF, which will be able to process 17 MMcm/d of gas. The CPF will be located north of the town of In Salah and tied back to the existing producing facilities in Reg. Gas will then be transported further to the Krechba CPF for CO2 removal followed by export to both the local community and Europe.
ISG Limited President Mohamed Keddam says that the ISG project is the first development project in central Sahara, “starting from nothing.”
“No existing infrastructure, no electricity, no communications. In other words, we have to build and produce everything we need,” Mr Keddam says. “The CO2 content of the gas is high (up to 10 per cent) which makes it challenging from a corrosion point of view. We have also been the first project to capture and sequestrate CO2 daily and on an industrial scale with a rate of 2 MMcm/d.”
Overcoming design challenges
The ISSF joint venture contracted Foster Wheeler for front-end engineering and design (FEED), which commenced in September 2009 and was completed in July 2010.
Foster Wheeler says the environment was a challenge. “The region is primarily uninhabited desert, with the terrain varying from tall sand dunes formed from the predominant southwest and northeast winds, through different mountain plateaux, across rugged falaises (sharp 200 m-high, cliff-like escarpments), to valleys and dry riverbeds or wadis.
“The Southern Fields are also located in the Ahaggar National Park, an area of environmental sensitivity with numerous historic and archaeological sites and an old palm oasis. In addition, In Salah is one of the warmest inhabited places on earth, with summer temperatures peaking at 63°C.”
Foster Wheeler says that developing pipeline routings through the multi-faceted terrain involved the latest satellite imagery, aerial survey and software technologies for producing detailed topographical terrain mapping.
“The Southern Fields project covers an overall area of 2,000 sq km and the pipelines constitute around half of the overall project cost, so it is vital to get the routing right. ISG pre-FEED work had already resulted in the acquisition of a considerable volume of geo-referenced data. Using Esri ArcGIS software, we developed this and subsequent data into a geographical information system model which will eventually be passed onto the engineering, procurement and construction (EPC) contractor,” says Foster Wheeler.
According to Foster Wheeler, a particular challenge during the FEED was the optimisation of the pipeline route.
The company says “In addition to a comprehensive land-based terrain evaluation survey by specialists in geology, geotechnical engineering and geo-hazard risks, a full aerial light detection and ranging (LiDAR) survey of the project area allowed for extensive review of the pipeline routes, taking into account both geotechnical and topographic assessments of the area in addition to the environmental constraints.
“LiDAR technology uses pulses of laser light striking the surface of the earth and measures the time of pulse return to produce a geo-referenced file, used for identification of broad land use or surface features.
“Pipeline construction is greatly affected by the operating constraints of plant and machinery, with side slope being of particular interest, impacting the choice of pipeline route,” added the company.
Mr Keddam says that the pipeline corrosion issue, caused by the presence of CO2, was addressed by using pipe that was 13 per cent chrome.
“The other problem was the very uneven area which lead to the formation of liquids in the lower parts of the pipeline,” he added. “We have overcome this problem by using slug catchers.”
Moving into construction
Engineering works and procurement for ISSF have been ongoing since February 2011, with site construction scheduled for the fourth quarter of 2011. The main EPC contractor is Petrofac, with other contractors including Algeria’s Grand Travaux Petroliers and Entreprise de Genie Civil for installation and civil works, respectively.
The construction phase of the project will also face challenges. The remote location of the project has made logistics, communication and power generation difficult.
“We are overcoming these by offering attractive contracts to transport companies, and by giving priority to the installation of temporary power generation systems, construction of a temporary air strip and the erection of communication towers,” says Mr Keddam.
Exceedingly high temperatures and sand storms have also created a harsh environment for construction workers.According to Mr Keddam, the living quarters are equipped with air conditioning and work is halted during sand storms to protect the safety of the workers.
The project will adopt basic safety techniques during construction, including:
- Mandatory personnel protection for all workers;
- Compulsory requirement of a permit to work;
- No vehicle movement without a dedicated person outside to warn other workers;
- The permanent presence of a safety engineer in all places of activity;
- Speed monitors for cars to limit the speed to 80 km per hour; and,
- Rewarding workers for safe work.
In regards to ISG’s safety policy, Mr Keddam says “Safety is not only a specialist matter; everybody is obliged to stop any work if it is not being done safely, and no work is worth being done if it is not safe.”
According to Mr Keddam, the project will create approximately 500 temporary direct jobs during construction and 200 permanent jobs once completed. He adds that while ISG intends to maximise the use of local suppliers, the project will require more than a hundred different suppliers of goods and services, forcing the proponent to look beyond the local community.
“We encourage the EPC contractor to use maximum local suppliers,” Mr Keddam says. “The local integration is estimated to be about 25 per cent.”
First gas is expected in the last quarter of 2013, with project completion scheduled for the first quarter of 2015.