Heavy Oil Science Centre - Overburden

Home
What's Heavy Oil?
Geology
Drilling
Completions
Transportation
Upgrading
Refining
End Users
Heavyu Oil History
Heavy Oil People
Heavy Oil Links

Serif - Inspiring Creativity



 

Cable Tool Rig

When the first commercial oil well in North America was drilled at Petrolia, Ontario, in 1858, a cable tool rig was used. Cable tool rigs had been in use for hundreds of years. They were used to drill for fresh water or for brines that were evaporated for salt.

The cable tool rig was also used in such early Alberta fields as Turner Valley, and they were used to drill (punch) all the early wells in the Lloydminster area.

cabletool.jpg (47877 bytes)

Cable tool drilling first involved the construction, on site, of an 82 foot high wooden derrick, built on a foundation of huge timbers. The legs were made of 2" x 12" rough lumber laminated to form a right angle similar to angle iron.  These were braced with horizontal girts and diagonal struts. 

On the derrick floor, there were three cable reels [see diagram to right] wound with steel cable which ran up and over the shives in the crown blocks.  One cable was the drilling line, one for the bailer, and the other for lowering and pulling the casing.   There were also three large wheels operated by power from a steam engine which sat just a few feet from the derrick platform.  The platform ran out from the derrick floor and on it was mounted the sand reel which contained the sand line.

The bailer was used to bail out the cuttings and water from the bottom of the well.   A few feet closer to the derrick was mounted the band wheel, operated directly from the engine.  Also mounted on the platform, just off the derrick floor, was a well braced upright post, know as the sampson post, and on top of it, laying horizontally, and attached by a hinge, was a timber, tapering from the centre to either end, called the walking beam.  One end of the walking beam extended into the derrick as far as the centre of the floor and to it was attached a threaded bar called the temper screw.   At the lower end of the temper screw was a clamping device that gripped the drilling line to which tools were attached.  A bit, which was no more than a steel weight with a point on it, was suspended by a cable down the well.

The other end of the walking beam extended over the band wheel and was attached to it by a pitman and crank. As the wheel turned the crank, it raised and lowered the pitman and rocked the walking beam up and down on the sampson post, like a teeter-totter, raising and lowering the drilling tools. The bit, little more than a steel weight with a point on it, pounds the well into the ground.

When the driller started his shift, he would feel for the bottom of the hole by gently lowering the bit until it rested on bottom.  This he could tell by taking hold of the drilling cable with his hand.  When the bit hit on bottom, he would feel a little slack in the line.  The driller would then put a mark on the line so many feet above the derrick floor, allow a little slack in the line and put the rocking beam in motion, raising and dropping the bit as it pounded away at the bottom of the hole. By taking hold of the drilling line from time to time, he could tell what was going on down in the well.   When there was no more slack in the line when the beam was in its lowest position, the driller would have to let out a little more slack. He had to be careful not to let out too much slack or the line could spring up and kink.

BitRack1.jpg (43453 bytes)After some drilling, the bottom of the well became clogged with rock chips. The bit was then raised and a bailer lowered into the well to scoop out the rock chips. After the bailer was removed, the bit was then lowered into the well to pound it deeper. This sequence was repeated about every 3 feet.

When it became necessary to lower casing into the well, the calf wheel (mounted just inside the derrick) and the casing line reel were turned to operate the travelling block.   A little further in on the derrick floor was another upright post, called the headache post.  This was just high enough so that when the walking beam was at its lowest position over the derrick floor, there was still some clearance between it and the headache post.  This was a safety feature to keep the walking beam from dropping if anything came lose at the other end of the beam.

Cable tool drilling was very slow. Cable tools do not effectively control subsurface pressures, and blowouts were common in cable tool operations. All the early wells in the Lloydminster area were drilled using cable tool rigs. One of the earliest wells found oil in September of 1929. The Oxville Oil, Gas and Development Company was a pioneer in what became known as the Dina Field near the junction of the Battle River and Ribstone Creek. Just outside of town, the famous Lloydminster Gas Company Number 1 brought in natural gas on Good Friday, March 30, 1934. The lead operator of the cable tool drilling rig that day was Charlie Mills. Charlie was born in Iowa and came to Canada as a youngster, working as a roughneck on cable tool drilling rigs in the Turner Valley. In 1929, he brought in the discovery well in the Viking-Kinsella Field.

Charlie is credited with bringing the first Rotary Drilling Rig into the Lloydminster area, about 1940. It was powered by twin V-8 engines.

cabletools.jpg (27436 bytes)

Tools from the Cable Tool Era

Left to right:

  1. Swedging tool: dropped down through the tubing to remove any kinks, dents, or (sometimes) obstructions.

  2. Drilling jars: connect the smashing bit, which rises and falls with the motion of the walking beam above, to the drilling bit so that each blow solidly hits the drilling bit.

  3. Fishing tool: one of several devices to hook, grab or otherwise retrieve lost or broken tools down hole.

  4. Drilling bit: the device that literally is punched through 100's of meters of overburden to reach the hoped for pay zone.

  5. Fluid bailer: device that is repeatedly lowered and lifted out of the well bore to remove fresh water, salt water, or oil.  Sometimes this is to clear the wellbore, other times it allows the visual observation of what is in the bottom of the well bore.