Pioneering India’s coal-bed methane development

Great Eastern Energy Corporation Ltd (GEECL), which is working on a concession in West Bengal, is the first private sector company in India to work on the potential of CBM as a fuel to help meet India’s fast growing energy needs.
India is currently consuming 140,000 MW of electricity per year, approximately 55 per cent of which is thermal based and derived from coal.
If the country is to meet its projected GDP growth rates for the next five years, an additional 100,000 MW of power capacity would be required, the additional capacity being predominantly coal based.
GEECL, which is listed on the London Stock Exchange's Alternative Investment Market, is through its harnessing of CBM also helping to maintain the ecological balance in West Bengal's coal bearing areas, where methane gas is escaping into the atmosphere and damaging the ozone layer.
The energy specialist is using an Atlas Copco RD20 drill rig linked to an Atlas Copco XRVS 1250 CD 6 portable compressor and a Hurricane booster supplying auxiliary air to pioneer exploration and development of coal-bed methane (CBM).
Prashant Modi, president and COO of GEECL believes that the time has now come for CBM to emerge as an important fuel resource.
"The thought was, if India has the fourth largest reserves of coal in the world, certainly there is a CBM opportunity in India," he said.
With a Petroleum Exploration License granted by the Indian state of West Bengal, GEECL began exploration with three pilot production wells.
Modi said that being a pioneer meant that everything had to be learned from scratch, with the only production methods that could be used as a model being those in the United States.
"It was hard to find drills in the beginning because it was not cost effective for a contractor to come in and drill the few wells," he said. Over the next few years, 20 wells were completed by contract drilling companies. But because of the volume of drilling GEECL was forecasting - 300 wells in the block - the company decided to purchase its own rig.
"We want to do things right and that means not cutting corners or quality," says Modi.
When they were looking at drills, their choice was influenced by the depth capacity of the RD20 and Atlas Copco's commitment to the Indian market, and the fact that the RD20 was designed for the CBM industry.
With the purchase of a new Atlas Copco RD20 drilling rig and plans to add a second rig in the very near future, the company expects to drill 100 wells in the next 2.5 years and 50 to 60 wells a year thereafter.
The RD20 has an onboard compressor delivering 350 psi of pressure at 1250 cfm.
To speed up the drilling of the large number of exploratory wells, an XRVS 1250 auxiliary compressor was added to the drilling operation, the air from the two compressors being combined and fed through the Hurricane booster and vented directly into the discharge line. The wheeled XRVS is fitted with a CAT C-18 ACERT III engine and delivers 1273 cfm at 365 psi.
Because CBM is similar to natural gas, it can be easily integrated with India's emerging compressed natural gas (CNG) infrastructure.
This region of India, known as the Raniganj Coal Belt, offers a large industrial customer base for GEECL. The region is largely rural but because of the coal reserves, it has a strong industrial base.
Modi points out that the gas they are selling will offer these cities the opportunity to reduce greenhouse gas emissions.
"India is currently importing 70 per cent of its hydro carbon fuels and increased usage of CNG will help reduce our dependence on oil imports," he said.
The concession block secured by GEECL has been very successful. The formation holds 10 seams of coal, each producing gas. The drilling depths average 3,300 ft (1,000 m) with the deepest well to date at 4,167 ft (1,270 m), the RD20 drilling and casing the deepest holes in only five days.
Chief driller Jerry Tennel, originally from West Texas, has experience with double and triple conventional rigs as well as 25 years in the business.
Tennel said that the onboard compressor and the XRVS 1250 together are being used to drill the holes, piping the air through the booster.
"We have more than enough air," he said. "We were running the onboard air and the XRVS 1250 auxiliary compressor boosted to 800 psi at the 4,167 ft depth."
CBM wells in India are very similar to shallow natural gas or oil wells. From the surface, a 17.5 inch (45 cm) hole is set with 14 inch (35 cm) conductor casing. A 12.25 inch (31 cm) is then drilled and set with 9 inch (24 cm) surface casing. To complete the well, an 8 inch (20 cm) hole is drilled and set with 5.5 inch (14 cm) production casing. These holes are drilled with air circulation using the Atlas Copco TD80 and QL120 down-the-hole hammers.
With the initial production wells, GEECL fracked and produced CBM from two of the 10 coal seams drilled. The company reports that the first 23 wells are producing 2.5 million cubic ft per day (mcfd).
When complete, the goal for this block is to produce 100 to 150 mcfd. Modi is confident that will happen. GEECL's crews are moving as quickly as possible, with the drilling forecast at three wells a month per drill when they are at full capacity.
Pipelines are currently being constructed ahead of the well development so that the gas can be sold as soon as the wells are fracked and producing gas.