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Photo by Joe Moylan

Generator houses from Rig 111 rest on truck trailers at the corner of Ranney and First streets in Craig. The rig finished its drilling operations on Harper Hill near Hamilton this week and is being transferred to Casper, Wyo.

Photo by Joe Moylan

A truck pulls out onto First Street in Craig on Friday trailing a mud tank from Rig 111 bound for Casper, Wyo. Rig 111 had been atop Harper Hill in Hamilton conducting stick pipe drilling operations on behalf of Shell Oil Company.

Photo by Joe Moylan

Pictured is Rig 94 at Shell Oil Company’s Durham location about a half-mile south of Harper Hill on Moffat County Road 37. Like at Harper Hill, a spokeswoman for Shell said the company is drilling two horizontal wells on the Durham pad.

Shell Oil Company announced Tuesday it is moving on to the next phase of drilling at its location atop Harper Hill.

“We finished drilling on the Harper Hill location, and that rig has been moved offsite,” said Carolyn Tucker, community relations representative for Shell. “We’re moving in a smaller rig to complete the wells to see if there is any flow.”

A stick pipe rig — Rig 111 — has been working at the junction of Colorado Highway 317 and Moffat County Road 37 since mid-August, drilling two separate horizontal wells from one pad.

Tucker said the Harper Hill wells were first drilled to a depth of 3,500 feet, then 3,000 horizontal feet. Each well is composed of more than 200 sections of pipe measuring 30 feet each.

Rig 111 was in transit Friday to make way for a smaller coil rig, which will arrive soon, Tucker said.

Coil rigs, unlike the stick pipe drilling rig, feature a continuous length of steel or composite tubing that is flexible enough to be wound on a reel for transportation.

The coil is inserted into an existing string of pipes to serve a number of functions including cleanout and perforation of wellbore casing, as well as retrieving and replacing damaged equipment.

“The coil goes down the well and then horizontal following the path of the well we’ve drilled,” Tucker said. “We’ll then pressurize the casing with a perforating gun to blow out holes in the pipes in certain areas where we think there is oil and where we want the flow to begin.”

Tucker said the sections of pipe that they pressurize would look similar to a colander as a result of the perforation activity.

However, where it is the purpose of a colander to drain fluid from food, as with cooking pasta, the purpose of blowing holes in a pipe is to allow oil to seep into the wellbore. As oil flows into the pipes, pressure builds forcing the liquid to the surface.

“That’s how we get oil to flow up the wellbore,” Tucker said. “We expect the oil to flow naturally.”

Tucker said they expect to see oil by Dec. 8 if not earlier.

Shell is conducting another drilling operation at its Durham location about a half-mile south of Harper Hill.

The stick pipe rig in that location — Rig 94 — has already finished drilling one well and is in the process of drilling a second from the same pad.

Rig 94 had been held up by the Colorado Department of Transportation in October and was weeks late in arriving at the site.

But, it appears the holdup may work in Shell’s favor because the Harper Hill wells will be completed about the same time drilling operations are finished at Durham.

“As soon as completion work is done at Harper, we’ll just transfer the coil rig around the corner to start completion work at Durham,” Tucker said. “Completion and flow are expected at the Durham location by the first or second week of January. Then, we’ll close up operations for the winter.”

Although the goal is to see oil flow at both locations by the first week of 2012, Shell does not plan to begin serious commercial production until spring.

However, Tucker said two of the five wells the company acquired from the purchase of Pennsylvania-based East Resources in 2010 have been upgraded and are currently producing 80 to 100 barrels of oil per day.

Those wells are located off Moffat County Road 37 in the Waddle Creek area.

Tucker said there is no timeline to bring the three remaining Waddle Creek wells online.

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