Drilling advances

	Vol. 226 No. 7
LES SKINNER, PE CONTRIBUTING EDITOR

Look how far we’ve come. The popular image of the oil business in general – and the drilling business in particular – continues to suffer under the onslaught of misdirected, ignorant, self-appointed saviors of the planet.

Perhaps a review of offshore drilling history would be useful to these distracters – if they would bother to read it. The offshore drilling industry is marking its 50th anniversary of some important firsts this year. Ours is a relatively young industry compared to others in commerce; and offshore work can be perilous to say the least. We have had the same growing pains as other industries compressed into a very short lifetime; i.e., we have had to clamber up a very steep learning curve; and we continue that climb today as we advance into deeper waters.

Early offshore wells were actually drilled from wharves built into the sea from shore. The first, according to J. E. Brantly in his book History of Oil Well Drilling, took place in California in 1897. This well was likely drilled with cable tools, and the wharf was probably very narrow, without a turnaround at the end. I would imagine that backing the drawworks on a horse-drawn wagon to the standard wooden derrick at the end of that wharf was a real feat.

Wells along the coasts of Texas and Louisiana were drilled in the early 1900s by extending earthen pads from the shoreline. Parallel efforts were underway in other parts of the world. In 1949, operations began from an artificial island off Azerbaijan. The “Oil Rocks” project involved a whole city built into the Caspian Sea. Eventually, the island was expanded and connected to the shoreline by a long earthen causeway. Later, permanent structures were used in deeper waters. Some were platforms constructed of wooden piles driven into the seafloor, topped by timber topsides on which derricks were constructed. Others had concrete foundations sitting on the seafloor. Pumps, pits, boilers and other systems were mounted on tender barges moored next to the structures. For the next several years, 90% of offshore wells were drilled using this system.

After WWII, the same concept was extended into open water in the Gulf of Mexico. This was the system Kerr-McGee Corp. used to drill the first out-of-sight-of-land well in Ship Shoal Block 32. Kerr-McGee’s partners in the venture were Phillips Petroleum Co. and Stanolind. The tender barge? The Frank Phillips.

Drilling rigs underwent several design changes over the next few years. One was the introduction of the submersible drilling barge. In this design, an elevated platform was built atop a large, shallow-draft barge that was sunk at the wellsite. The rig, with a jack-knife derrick, would all be above the water line on a secure structure unaffected by waves. After drilling, water was forced out of the barge, the rig was re-floated and moved to a new site where it was sunk again. The first of these was built in 1954 by A. J. LaBorde, who formed Odeco with John Hayward and Charles Murphy, Jr. The rig was named Mr. Charlie after Murphy’s father.

Also in 1954, the world’s first jackup rig went into service. Offshore Rig 51 was a joint venture between SONAT, J. Ray McDermott and DeLong. The rig had 10 legs, each 6 ft in diameter and 160-ft long. Each was fitted with a large spud can to limit penetration into the seafloor. It was limited to a 100-ft water depth. The Mr. Gus was commissioned in 1954 and sold to Glasscock Drilling Co.

A significant breakthrough occurred in 1955. R. G. LeTourneau hatched an idea for a mobile bottom-supported rig capable of drilling in deeper offshore waters. His company conducted extensive engineering studies in oceanography, hurricane winds and tidal forces. His idea was to have a drilling platform that could be floated to the site, and jacked up on three independently controlled, lattice-type legs, well above the splash zone. His design became the forerunner of today’s three-leg jackups.

LeTourneau then approached investors with a novel proposal. He asked for a $400,000 advance (refundable if the idea didn’t work) plus another $550,000 if the design succeeded, plus stock in the investor’s company. The man he approached was George H. W. Bush, later the President of the United States. The investor’s company: Zapata Off-Shore Drilling.

In December, 1955, Scorpion walked under its own power into the Mississippi River. The derrick, drawworks, pumps and other equipment were added to the deck, and the rig went into service drilling off the coast of Texas. In June, 1956, it set a record by jacking down off one well, moving to another site and spudding a new well in 8-1/2 hours.

LeTourneau delivered a second mobile offshore drilling unit to Zapata in 1957. Both withstood the fury of Hurricane Audrey later that year, with essentially no damage – the only rigs in the Gulf of Mexico to prove themselves resistant to these raging storms.

In 1961, Shell Oil converted an existing submersible drilling rig into the first semisubmersible unit for work in the Gulf of Mexico. This allowed for stable drilling in water up to 600 ft. The design was successful and the fleet was expanded, along with offshore exploration.

These designs were followed in rapid succession by others for special purposes including the first new-construction, purpose-built drillship, the Glomar II by Global Marine. It went to work in the Cook Inlet in 1962. Also, in 1962, Reading & Bates built the C.P. Baker, a catamaran hull design for work in the Gulf of Mexico. In 1963, The Offshore Company built the first center turret mooring system into its Discoverer I. This feature allowed the ship’s bow to point into the waves regardless of direction, providing greater stability and, therefore, the capability of drilling in deeper waters.

And on the story goes. Now, deepwater wells are drilled in seawater depths over 10,000 ft. Risers/ drillstrings are subjected to previously unknown forces. Ocean currents/ eddies require vortex shedders on large-diameter risers. Special handling systems are needed to run and latch-in these risers to drill safely at water depths approaching two miles.

What was risky or outright dangerous in 1955 is now commonplace. Inventors, entrepreneurs and companies like those noted above, provided the industry with designs that allow us, and those around the globe, to pursue drilling in areas that could only be explored in the imagination of oilmen prior to that time. Our hats are off to these pioneers. 

Les Skinner, Consultant, Houston, and a chemical engineering graduate from Texas Tech University, has 32 years’ experience in drilling and well control with major/ independent operators and well-control companies.