The Gulf of Mexico (GoM) is one of the world’s great petroleum basins, boasting a hydrocarbon-producing history that spans more than 100 years. While some could say the GoM is getting a little long in the tooth, the explorers and producers of this legendary petroleum province would argue that it is just getting its third—possibly fourth—wind and that a renaissance is underway. Driven by advancements in technologies that range from helping to decipher the resources lying under miles-thick layers of salt to safely tapping and recovering those resources in a variety of ways, the GoM continues to astound all that choose to work in it.

Continental washbasin

The petroleum riches of the GoM are due to its unique geology and the richness of the many streams and rivers that flow into it, the greatest of which is the Mississippi River. It is a river known by many names: Old Man, Big Muddy or Great. From its start at Minnesota’s Lake Itasca, the Mississippi River flows through 10 states before emptying into the GoM. Forming the largest drainage system on the North American continent, the Big Muddy and its many tributaries drain all or parts of 31 U.S. states and two Canadian provinces between the Appalachian and Rocky Mountains, according to the U.S. National Parks Service.

It is a fertile system that has fed the GoM with sand, silt and more over the millennia, contributing to a hydrocarbon generation process that traces its beginnings back to the time of Pangea.

The GoM is a Mediterranean-type sea that measures about 1,600 km (994 miles) from east to west and 900 km (559 miles) from north to south and has a surface area of 1.5 million sq km (579,153 sq miles), according to the Gulfbase.org website.

The GoM basin resembles a large pit with a broad shallow rim. About 38% of the Gulf is comprised of shallow and intertidal areas (less than 20 m [66 ft] deep), the website said. The area of the continental shelf (less than 180 m [590 ft]) and continental slope (180 m to 3,000 m [9,843 ft]) represent 22% and 20%, respectively, and abyssal areas deeper than 3,000 m comprise the final 20%, according to the website.

The present GoM basin is believed to have had its origin in Late Triassic time as the result of rifting within the North American Plate at the time it began to crack and drift away from the African and South American plates, the website said.

Intermittent advance of the sea into the continental area from the west during late Middle Jurassic time resulted in the formation of the extensive salt deposits known today in the GoM basin. It appears that the main drifting episode, during which the Yucatan block moved southward and separated from the North American Plate and true oceanic crust formed in the central part of the basin, took place during the early Late Jurassic, after the formation of the salt deposits, according to the website. The basin has since been a stable geologic province characterized by the persistent subsidence of its central part, probably due at first to thermal cooling and later to sediment loading as the basin filled.

Auspicious beginnings

Even legends have to start somewhere, and for the GoM’s offshore oil and gas industry, that start would be at the Creole Field. Located 1.9 km (1.2 miles) from the shores of Cameron Parish and 21 km (13 miles) from the nearest coastal community of Cameron, La., the field was operated by Pure Oil Co. and Superior Oil Co. The 2,787-sq-m (30,000-sq-ft) platform was built on timber pilings in water depths of 3 m to 4.5 m (10 ft to 15 ft).

Years later, Kerr-McGee became the first operator in the world to drill “out of sight of land” at Ship Shoal Block 28. The Kermac No. 16 well stood in almost 6 m (20 ft) of water, 16 km (10 miles) at sea, according to the American Oil and Gas History Society website. The well was spudded Sept. 10, 1947, and on Nov. 14 the well came in at 40 bbl/hr. By 1984, the well would produce 1.4 MMbbl of oil and 8.7 MMcm (307 MMcf) of natural gas, according to the website. By the end of 1949, 11 oil and natural gas fields were found in the GoM with 44 exploratory wells, according to the National Ocean Industries Association.

The GoM has grown considerably in the years since Creole. Federal offshore oil production in the GoM accounts for 17% of total U.S. crude oil production, and federal offshore natural gas production in the Gulf accounts for 5% of total U.S. dry gas production, according to a U.S. Energy Information Agency fact sheet.

Recent discoveries

Surrounded by the U.S. to the north and Mexico to the south, discoveries have been made on both sides of the maritime border.

On the U.S. side, major discoveries announced in 2015 include Chevron’s Anchor prospect in the deepwater GoM. It is the company’s second discovery in the deepwater Gulf in less than a year, according to a company-issued press release.

“The Anchor discovery, along with the previously announced Guadalupe discovery, are significant finds for us in the deepwater Gulf of Mexico. We had one of our best years with the drillbit in 2014, reporting more than 30 discoveries worldwide and adding an estimated 1 billion barrels of new resources to our holdings,” said Jay Johnson, senior vice president for upstream, Chevron Corp., in the release.

The Green Canyon Block 807 Well No. 2 encountered oil pay in multiple Lower Tertiary Wilcox Sands. The well, which was spudded in August 2014, is located about 225 km (140 miles) off the coast of Louisiana in 1,580 m (5,183 ft) of water and was drilled to a depth of 10,287 m (33,749 ft). Appraisal drilling will begin in 2015.

At a June conference in Guadalajara, Mexico, Pemex CEO Emilio Lozoya announced the discovery of four new shallow-water fields in the GoM, according to a Bloomberg article.

The fields hold the potential for daily production of at least 200,000 bbl of oil and 4.8 MMcm (170 MMcf) of gas, Lozoya said following the Oil Workers’ Conference. The wells, forecast to begin production within 16 months, are located close to the Cantarell Field, one of the world’s largest when it was discovered in the 1970s.

The discoveries come after Mexico approved final legislation last year to allow foreign producers to explore and help develop oil in the country for the first time in more than seven decades, Bloomberg reported.

“This is the first tangible result of the energy reform,” Lozoya told reporters following the inauguration of the conference. “Pemex, thanks to the energy reform, is accelerating plans to incorporate private capital in exploration and production of our wells.”

The discoveries were made in areas of the GoM that Pemex maintained last year as part of the noncompetitive bid round, known as round zero. They are close to 14 shallow-water blocks that private companies will bid on next month, the report said.

Comments