Oil and gas enthusiasts, from exploration through production, look toward the future in a quest to find more efficiency, less cost, additional reserves, faster production and a broader margin between revenue and expense.

The pressure is constant, and the search for the technology that takes another step closer to those goals often frustrates even the most optimistic professional. That situation has existed for decades, and occasionally a look back at the obstacles previous generations conquered helps put the chase in perspective.

Back in the late 1960s, for example, popular wisdom held that the water depth limit for cable and chain mooring was 600 ft (183 m) and a vessel would have to use dynamic positioning to drill in water deeper than that.

Operators knew they could handle those depths. Research vessels using dynamic positioning had taken cores from 5,000 ft (1,525 m) of water by that time, and the Glomar Challenger had the capability of taking cores in 20,000 ft (6,100 m) of water. It’s just that drilling for production in ultradeep water — more than 1,000 ft (305 m) at the time — needed better technology.

Now, with the help of polyester mooring lines used for years by Petrobras offshore Brazil and already in use in the Gulf of Mexico, mooring doesn’t appear to be a problem in any conceivable water depth.

By 1968, Humble Oil, holder of the water depth drilling record at 600 ft (183 m) in the Santa Barbara channel, more than doubled that feat with a well in 1,300 ft (396 m) in the same benign waters.

By the end of that year, Ocean System Inc. proposed a new type of drilling and production system, a submerged, manned capsule 150 ft (46 m) below the surface and supported by 18 conductor legs. During drilling operators, the capsule could support a jackup rig that would drill through the conductor pipe. The pipe was angled so the jackup could drill without changing locations. The multideck capsule would allow simultaneous drilling and completion or workover operations.

The company designed one capsule with a 40-ft (12-m) diameter and another with an 80-ft (24-m) diameter. Obviously, these capsules would cost more to operate than a surface platform, but the advantages multiplied as the water got deeper.

The concept was popular enough that the industry even conducted tests with a submarine work boat to test the feasibility of changing shifts on the submerged capsule.

The search for workarounds to the supposed mooring limitation continued, but it was a conservative search. After all, there was no big hurry. More than 70% of the world continental shelf was in less than 600 ft of water.

By 1971, the Ocean Prospector could drill in 656 ft (200 m) of water. It was the largest rig in the world at the time with 12 columns supporting the deck. The same year, W. Herbert Hunt, at the time manager of Penrod Drilling Co., said two semisubmersible rigs were due out of shipyards in 1975 capable of drilling in 3,000 ft (915 m) of water. The following year, Exxon (then Esso) signed a construction contract to build two vessels capable of positioning and anchoring drilling vessels in that water depth.

Buoyancy modules took 90% of the weight of drilling risers off the top tensioners. By early 1974, an Ocean Drilling & Exploration Co. (Odeco) semisubmersible could drill moored in 1,500 ft (458 m) of water and could be modified to work in twice that depth.

About the same time, Shell was building the first spar platform for storage and offloading work in the North Sea, a step toward deeper water production. Looking at alternate technology, 17 operating companies agreed to test the tension leg platform concept developed by Deep Oil Technology Inc. with a prototype triangular one-third scale model offshore Southern California.

Incredibly, in just 8 years from 1968 to 1976, the industry moved the water depth drilling mark from 600 ft to 2,200 ft (671 m) with the help of dynamic positioning and technology that moved weight off the drilling platform. The 3,000-ft mark was just around the corner.

At the same time, production from water in 1,000 ft hovered in the near future, and the first spar was setting the scene for Shell’s planned Perdido Hub in 8,000 ft (2,439 m) of water in the Alaminos Canyon area of the Gulf of Mexico. Tension-leg platforms were setting the scene for production with that technology from 4,000 ft (1,220 m) of water.

In 1977, industry was meeting and handling challenges to technology and equipment that would allow it to drill and produce in 3,000 ft of water.

Thirty years later, it faces the same kinds of challenges as it considers production from 10,000 ft (3,050 m) of water. Chevron already beat that drilling mark with its Toledo well in 10,011 (3,053 m) of water near the southern limit of the Alaminos Canyon area in the Gulf of Mexico.

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