First Steps Offshore

From ETHW
Revision as of 16:43, 21 July 2015 by Administrator7 (talk | contribs) (→‎Seismic Goes Offshore)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Contributed by Mark Mau and Henry Edmundson

While exploration matured on land and men’s understanding of the reservoir took its first steps, the industry had been quietly moving into the sea. Geologists had no doubt that the same conditions that produced gushers on dry land would be equally prevalent offshore. It was simply a matter of figuring out how to transport the entire industry into the water.

California and Venezuela

The first well drilled offshore was at Summerland Beach, north of Los Angeles. There, in the late 1890s, members of a Spiritualist community led by Henry Lafayette Williams began drilling onshore to capture oil and gas seepages. They noticed that the nearer the well was to the ocean, the more it produced. In the tidal area, gas even bubbled to the surface, indicating that underground reservoirs stretched beyond the shoreline. Reaching them, however, seemed an insurmountable challenge.

Williams then had the idea of building a wooden staging dock, perpendicular to the beach, to drill from. Williams built the first such pier and placed a cable-tool drilling rig at the end of it in 1897, thus claiming the earliest offshore drilling and production platform. The power generators and other supporting equipment remained along the beachfront. His first three piers extended some 1,350 feet from the shoreline, with water depths reaching 35 feet. Williams’s crew pounded their way 455 feet down to two oil sands.

Williams’s days were numbered, however. In 1898, during an inspection of his four active onshore wells, Williams stumbled and fell into an abandoned well. Weakened by his injuries, he fell ill with pneumonia, was taken to San Francisco for medical treatment and passed away on January 13, 1899, at the age of 58. His family grieved over his death but others didn’t. He was venerated for his oil drilling, but many in his community not persuaded by his spiritualist leanings were glad to see the back of him.

Meanwhile, other Summerland entrepreneurs started to build piers, jutting seaward beyond the crashing surf. By 1900, there were 12 piers protruding into the ocean, and 22 operating companies drilling in search of oil. By 1903, 198 wells were in operation. Summerland wells continued to produce until the late 1930s.

These offshore wells had a spin-off effect for drilling in shallow inland waters. Most important was Caddo Lake in Louisiana. The discovery of the Caddo field goes back to 1870 when a water well near the lake’s south shore accidentally hit a gas reservoir. In 1902, another water well hit natural gas in significant quantities. Soon bona-fide oil prospectors came to the region hoping for another Spindletop. Among the first was the Gulf Refining Company of Louisiana, whose drilling superintendent, Henry A. Merlat, began constructing a wooden drilling platform in the lake. In the spring of 1911, Gulf started drilling operations on its first oil well in inland waters.

The next milestone was the development of movable offshore drilling units in the mid-1920s. The Texas Company, founded just after the Spindletop discovery and later to become Texaco, first proposed augmenting wooden-piled drilling platforms with mobile steel barges that could hold some of the drilling machinery. The reason was simple: wooden drilling platforms were expensive and easily damaged, and if a well was dry, crews had to remove the entire rig from the platform, return it to dry land or transport it piecemeal to drill the next well. Mounting the rig on a barge reduced mobilization costs as well as overall platform deck size. When the Texas Company tried to file a patent, the company was shocked to learn that a certain Captain Louis Giliasso, US citizen and merchant mariner turned driller working in Lake Maracaibo in Venezuela, had already claimed the idea.

The Lake Maracaibo fields were discovered in 1917 by Shell with moderately successful wells drilled on the lakeshore. Then, in 1923, Shell drilled a 100,000 barrel-a-day gusher and operators everywhere scrambled to get the best shoreline blocks. A drilling frenzy ensued. Shell continued working the shoreline, while Gulf and Lago Petroleum concentrated on the lake itself. Between 1924 and 1928, Lago Petroleum began drilling wells in the lake using wood piles and later concrete piles to support the rig.

During this first Venezuelan oil boom, Giliasso used his shipping know-how to design a submersible barge that could rapidly move a drilling unit between locations, and he was awarded a patent for the idea in 1928. Giliasso tried to sell the barge idea to several Lake Maracaibo operators, but all doubted that a barge resting on a mud bottom could ever be refloated. The suction, they said, would hold the barge fast to the bottom. Giliasso argued his case but could never persuade anyone to try it.

The Texas Company, on the other hand, was convinced it would work but needed Giliasso’s patent. Following an exhaustive search, the company located the former mariner in Panama running a bar. The Texas Company bought the rights to the patent and in 1934 completed the construction of the first submersible steel drilling barge, naming it Giliasso in the captain’s honor. It was towed to a shallow, open-water section of Lake Pelto on the Louisiana coast, about 40 miles southwest of Houma, and the Texas Company started drilling. The Giliasso was a triumph of innovation and efficiency, cutting the move from one well to the next to just two days. Other oil companies were soon copying the design.

Out of Sight of Land

The Giliasso, however, was just the beginning. Growing energy demand, particularly following World War II, moved oil producers to drill offshore and do so more efficiently. Most urgent was a complete offshore drilling rig that was maneuverable in the open ocean. Mobile barges could transport equipment from one platform to another, but the drilling platforms themselves were permanent, and installing permanent piled platforms for every exploration well was getting far too expensive and time-consuming.

In 1946, Oklahoma-based Kerr-McGee Oil Industries, named for its two principals Robert Kerr and Dean McGee, developed a mobile drilling platform and drilled an exploration well 12 miles off the coast of Louisiana. It was the first oil well ever drilled out of sight of land, albeit in water only 18 feet deep. The Kerr-McGee drilling platform consisted of a small platform with derrick and drawworks, and a separate floating tender to store the drilling equipment. Both could be moved separately and then rejoined to drill another well.

Then along came British marine engineer John T. Hayward, chief engineer at Barnsdall Oil Company in Tulsa, Oklahoma. In 1949, Hayward designed and built the first integral, movable offshore drilling rig, the submersible Breton Rig 20, that could work in up to 20-feet water depth and be moved from location to location with minimal delay and setup cost. The Breton Rig 20 drilled its first well in late 1949 to nearly 11,000 feet and continued drilling in the Gulf of Mexico until it was retired in 1968.

But the industry did not rush to embrace the Hayward platform. One enthusiast, however, was Alden J. “Doc” Laborde, formerly a Kerr-McGee employee. Laborde tried to interest Kerr-McGee in a new Hayward-type barge capable of drilling in waters up to 40 feet and withstanding winds of 70 miles per hour but met with rejection. Undeterred, Laborde eventually persuaded a group of investors led by Charles Murphy Jr. of Murphy Oil to form the Ocean Drilling and Exploration Company (ODECO), based in New Orleans. In late 1953, ODECO built its first offshore drilling rig—a floating, submersible drilling vessel—at a cost of US$ 2.5 million, named it Mr. Charlie after Charles Murphy Sr., and started drilling for Shell off the coast of Louisiana.

Meanwhile, the concept of the jackup began to emerge. Curiously, the idea can be traced back 100 years to an 1869 Scientific American article describing a certain Samuel Lewis’s invention of a “submarine drilling machine,” intended for drilling shot holes in the treacherous rocks of Hell Gate in New York Harbor to prepare for rock-removal by explosions, “It consists of a steamboat, and a device whereby the vessel, when the drills are at work, may be raised entirely above the waves, at which time its weight is supported by six adjustable pillars.”

The notion of a self-elevating platform for oil drilling was first realized in 1954 by Colonel Leon B. Delong of the US Army Corps of Engineers, who had designed temporary marine platforms during World War II. In 1952, he formed the Delong Corporation to produce the first jackup barges and drilling rigs for the offshore industry. Jackups elevate their platforms out of the water by extending, or jacking downwards, long cylindrical or triangular legs to the seafloor to create a temporary platform. Raising the legs then allows the jackup to be quickly floated to the next drilling location.

Seismic Goes Offshore

As drilling offshore matured, geologists tasked with picking well locations faced a dilemma. On land they could walk new prospects and study outcrops in minute detail. Offshore they were stymied, that is until seismic exploration learned to function in the marine environment.

The early offshore seismic surveys were made in shallow water using makeshift adaptations of land equipment. The first trial took place in 1938 when a Shell crew commandeered three 35-foot fishing boats, one for shooting and two for recording, and did a test survey four miles off the Louisiana coast in 65 feet of water. With no accurate means of navigation, the crew had to rely on spotters on the beach who triangulated the boats’s positions and communicated via two-way radio. A simple stick of dynamite lowered into the water provided a sound source, and the reflected signal was picked up by water-tight geophones attached to a steel plate heavy enough to remain seated on the seafloor. Superior Oil and Mobil used a similar setup in 1944 exploring for salt domes offshore Louisiana, and in March 1946, Shell dispatched its first, fully fledged offshore seismic party, Party 88, from the docks at Grand Isle, Louisiana.

It was Kerr-McGee that made the first offshore seismic survey out of sight of land, in 1946. This time the geophones were mounted on a cable, also designed to sit on the ocean floor. With the recording boat anchored, the geophone cable was lowered overboard. Meanwhile, the shooting boats fanned out and circled the recording boat at a radius of up to six miles, detonating dynamite charges every mile. If the water was shallow enough, they dropped the dynamite into pipes drilled into the seafloor. In deeper water, crews bundled up 50 pounds of dynamite, inserted a cap, and tossed the charge overboard.

A recurrent problem for Kerr-McGee was ocean currents or snagged debris breaking the cable. In 1947, German scientist Eugen Merten, director of the new Shell Geophysical Research Laboratory in Houston, solved the cable problem by floating it rather than weighting it to the ocean floor. But the real breakthrough came from Roy Paslay, who had been engaged in anti-torpedo research for the US Navy during World War II and afterwards joined the National Geophysical Company founded by the brother of Henry Salvatori. Paslay and colleagues patented an oil-filled float or streamer containing hydrophones—devices that are pressure sensitive as opposed to geophones that are motion sensitive—to pick up the incoming seismic energy, and in-built vacuum-tube amplifiers to maintain signal strength along the streamer. Their initial streamer consisted of eight 300-foot sections, each section containing three hydrophones.

Meanwhile fishing boats were replaced by modified Word War II mine sweepers and other war-surplus boats. The first single-boat acquisition system—in other words shooting and recording equipment on one vessel—was launched by Marine Instruments and deployed off the coast of Galveston, Texas, in 1947. Because the idea of a marine seismic service was so new, their boat was not always in demand. So in quiet periods, Marine Instruments became the first company to gather speculative or “spec” data, shooting seismic surveys in interesting areas and hoping to sell the data to prospective clients sometime in the future.

This entry is based on Groundbreakers: The story of oilfield technology and the people who made it happen, by Mark Mau and Henry Edmundson. You can find the book at www.fast-print.net/bookshop/1791/groundbreakers.