Filling the gap

February 19th, 2013 | Posted by in gray-four | T3W | Waterwell Drills

Drilling company covers tough jobs in tough territories

Oromia Water Works Construction Enterprise (OWWCE) is Ethiopia’s administrative government agency responsible for water projects in the Oromia Region. The region’s topographical picture shows mountains, arid deserts, agricultural plains and eroded ravines. OWWCE uses its Atlas Copco T3W water well rigs to get to the most difficult locations, often where there are no roads, to drill large-diameter water wells.

Drilling in this tumultuous region uncovers a similar variation in geology. Much of the region is mountainous with fractured shale, basalt and sandstone. The water is generally sourced in the sandstone strata. Ninety percent of the drilling is done by air hammer, but 10 percent is mud drilled in sand, gravel or alluvial sedimentations. A driller has to be alert to formation changes at any time.

Of nearly 240 wells that will be commissioned by Oromia’s regional government this year, 53 will be awarded to OWWCE. The Ethiopian government commissions up to 400 wells annually.

Understanding the mission

OWWCE is both a drilling and construction company focused on water projects. Unlike the private, or non-governmental organization, drilling companies in Ethiopia, OWWCE will work a water project from well through delivery.

OWWCE also does large scale commercial projects such as dams and municipal water systems.

Of the more than 2,000 employees, 237 work in the drilling segments of the business. They can have seven drills working at any one time, but for the deep and large diameter work they use the Atlas Copco T3W rigs. They own one each of the 30,000, 50,000 and 70,000 pound (135, 220, and  311 kN) pullback machines. The rigs use 900 or 1070 cfm, 350 psi (425, 505 L/s, 24 bar) onboard air for all drilling.

The T3W works well for OWWCE because of its mobility in the rough terrain, but also because it has a deck engine. Drilling Manager Kumo Kedir, said they put excessive time on the drive engine, and he doesn’t want to overwork the deck engine. Driving from one site to another could take days. Also, the crew could be sitting over a hole for 10 to 15 days drilling. Having a second engine balances out engine usage.

Hole construction

OWWCE often drills with a 21-inch tricone bit, cementing with 14-inch casing to 20 feet (6 m). They also use an Atlas Copco QL80 DTH  hammer and 12-inch bit and case with 10-inch steel production casing. They will use a 17-inch tricone to 650 feet (200 m) if the formation or design calls for it.

They occasionally drill a deeper telescoping hole if the conditions call for it. After the 10-inch casing they will continue with an 8-inch bit and case with 6-inch casing.

One hundred percent of the time they use welded casing for strength and integrity of the well.

Challenging projects

Of the projects selected for OWWCE, the method to the process is pretty straightforward. They are given jobs directly from the government. Kedir said “The wells we drill are often in the most difficult environments or situations.”

For example, they often work in Oromia lowland areas, including borders of Oromia Somali, Kenya and South Sudan, countries that have been in turmoil and civil war for years. Kedir said the government isn’t able to get contractors to bid on drilling projects near border towns. OWWCE must do those wells. “We go where others won’t. That’s just what we do,” said Kedir.

Formations also present problems for drillers. Drilling in broken formations and boring wells with mud and air drilling requires advanced skills. Kedir said they often get tasked to drill where independent contractors don’t have the skill level necessary. OWWCE’s drillers have years of experience. The crews literally live with the drill rigs moving the camp from one drill site to the next with the rig.

“We fill the gap,” Kedir said, speaking of their assignments. “We do what others won’t or can’t.”

At the time of this article, the company’s three T3W rigs were all completing wells to 200 meters, drilling 12 inches in diameter. “We often go deeper and drill more complex wells,” said Kedir.

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