Lifting liquid gold: A wider variety of extraction techniques are being examined

One of the most important trends within Bahrain’s energy sector is a general increase in production. This shift is taking place in both the oil and gas industries as well as the upstream and downstream segments, and the trend can be attributed to a number of factors, with the successful application of enhanced oil recovery techniques (EOR) being chief among them.

RESERVES: The Bahrain Field, which is located in the centre of the country and is sometimes referred to as the Awali Field, holds all of the country’s onshore oil reserves. According to Tatweer Petroleum (Tatweer), the company responsible for producing the field’s crude, the oilfield stretches across nearly 80% of Bahrain’s main island and measures about 5 km in width and roughly 15 km in length. Production at the field has been ongoing for a considerably long period of time, starting shortly after the discovery of oil in Bahrain in 1932.

With a relatively long history of extraction, the Bahrain Field was, by and large, considered to have been near the end of its productive life by 2008. However, new methods of production are making it possible to both continue and expand extraction.

“Exploration and production technology is only getting better and this enables production to continuously increase due to new discoveries,” Majeed Shafea, general manager at Chevron Bahrain, told OBG. “Around 30 years ago, roughly 35% of proven reserves were recoverable. Today, 60-70% of reserves are recoverable. This is already a doubling of the production rate.”

IMPROVING METHODS: Tatweer has been overseeing oil production at the Bahrain Field since late 2009 when it overtook the responsibility from the Bahrain Petroleum Company (BAPCO). Officially inaugurated in January 2010, the firm is a joint venture between Abu Dhabi’s Mubadala Development Company, the California-based Occidental Petroleum Company (Oxy) and nogaholding, which is the subsidiary as well as investment and development arm of Bahrain’s National Oil and Gas Authority (NOGA). Tatweer was established to gradually increase production at the Bahrain Field through the use of advanced technological methods. According to nogaholding’s most recent annual report, Tatweer aims to increase production by roughly threefold, ultimately extracting 100,000 barrels per day (bpd).

WATER, WATER: Tatweer implemented several EOR methods for the first time in the kingdom in 2011. For example, the company carried out a water flooding pilot project meant to extract light crude from the field’s Mauddud reservoir, which is located just below 762 metres, according to Tatweer figures. First proven to be a successful method of recovering oil in the 1950s and 1960s, this technique displaces residual crude via the injection of water. The water pushes crude from an injection point to a well used for producing the oil. There are some associated problems, however, such as variable permeability that negatively affects the transport of fluids within a reservoir.

Tatweer aims to further pilot the water flooding technique in more than six of the reservoirs located in the Bahrain Field. The firm may also expand the recovery method to other areas of each reservoir if the pilot projects prove to be profitable. It calculated in 2011 that the effective use of water flooding would expand the recoverable crude in the Bahrain Field by 10-20%.

FRACTURING: Additional EOR techniques used by Tatweer have focused on hydraulic fracturing. Commonly referred to as “fracking”, hydraulic fracturing was originally developed as a recovery method in the 1940s and involves pumping water and sand (as well as chemicals at times) under high pressure down a well. The pressurised mixture of water and sand creates cracks in the rock, making it easier to recover crude or gas. Tatweer is using hydraulic fracturing techniques in the Magwa and Ostracod reservoirs, where, over the course of some 34 days, approximately 14m barrels of gel and 2.8m barrels of sand were used to fracture nine wells. The process was carried out in 17 stages, according to Tatweer figures.

STEAM: The company has also piloted steam injection EOR methods, which fall under the broader category of thermal recovery techniques and are used on a large scale for recovering heavy oil in fields in Indonesia and California. Tatweer is concentrating its efforts on two types of steam injection. The firm aims to use a cyclic steam injection technique in the field’s shallow rubble reservoir. This involves injecting steam into a well for a number of days, after which the well is left alone for several more days to let the steam “soak”. The steam’s heat both diminishes the viscosity of the crude and fractures the rock, making it possible for the oil to reach the well more easily. Following the soaking period, extraction efforts are applied to the well. Steam injection is repeated when production levels drop below a certain point. According to Tatweer, the Bahrain Field’s shallow rubble reservoir holds over 1bn barrels of crude, of which Tatweer could extract a large percentage via the effective application of cyclic steam injection.

TESTING METHODS: The company is also working to pilot the use of another thermal recovery technique known as light oil steamflooding (LOSF). The method involves injecting steam into a reservoir in order to heat up residual crude to the point of vaporisation. Once vaporised, the oil is displaced to a well where it can be extracted. Unlike the cyclic technique, the LOSF method is implemented by injecting steam through a steam well rather than a production well.

LOSF efforts will be concentrated on the field’s Mauddud reservoir. In its 2011 annual report Tatweer calculated that even after a long history of gas injections, a substantial amount of residual crude is in fact still located in the Mauddud reservoir.

While its main development plan puts emphasis on implementing water flooding as well as two types of thermal recovery techniques, the company has also indicated that it is currently evaluating the use of other EOR methods such as injecting gas, chemicals or immiscible water-alternating-gas injection. If the firm chooses to carry out any of these recovery methods, they will be used concurrently with the waterflooding and thermal recovery pilot projects, respectively.

In addition to its employment of EOR techniques, Tatweer has substantially increased the number of new wells. According to its most recent annual report, the company drilled 173 new oil wells in 2011, 165 of which Tatweer put into production. This represents a considerable increase of more than 550% when compared to 2010, when the firm added 25 oil wells to production. The company also converted 88 wells from gas lift to beam lift and built three power substations in 2011. Tatweer’s yearly committed spend for 2011 totalled $1.4bn, an increase of over 300% when compared to the $345m spent the year prior.

SEEING THE EFFECTS: Although Tatweer only recently started its crude production operations at the Bahrain Field, the company has already recorded notable results. It achieved an average field production for both oil and condensate of 42,500 bpd in 2011, representing a rise of about 33% from average field production of 31,900 bpd in 2010. Average production for black oil grew by nearly 40% between 2010 and 2011, from 27,300 bpd in 2010 to 38,000 bpd the following year, according to figures cited in Tatweer’s most recent annual report. The company also provided an average available capacity of 53.8m cu metres per day (cmd) of non-associated gas in 2011, up from 42.5m cmd in 2010.

The recent completion of a new waste treatment plant should help Tatweer further increase its production capacity. Inaugurated in June 2012 and located in the Bahrain Field, the facility cleans up wastewater created as a by-product from oil extraction. The cleaning process is completed through a number of methods including induced gas flotation, nutshell filtration and a three-phase gravity separator. Treated wastewater can then be reused for steam flooding and waterflooding recovery techniques. According to NOGA, the project took approximately 18 months to complete, and investment in the plant totalled $16m.

MANY PLAYERS: While much of the attention on boosting hydrocarbons production is focused on Tatweer and oil extraction from the Bahrain Field, a number of other companies are also working to expand output. For example, Oxy was awarded a contract in 2012 to explore gas deposits in the country, and BAPCO, which currently owns and manages Bahrain’s only oil refinery, is taking steps to increase the facility’s production capacity from 267,000 bpd to some 360,000 bpd, according to figures from BAPCO.

Although located considerably further downstream, the Gulf Petrochemical Industries Company (GPIC) is also playing a key role in increasing the manufacture of energy-related products in Bahrain.

Established back in the late 1970s, GPIC is owned equally by three companies: the Kuwait-headquartered Petrochemical Industries Company, Saudi Basic Industries Corporation and nogaholding. The firm at present produces ammonia, urea products and methanol. According to nogaholding’s most recent annual report, GPIC reached a record level of production in 2011, increasing daily output by around 2.5%. Cumulative production also jumped from about 16m tonnes in 2010 to approximately 17m tonnes the following year.