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Insight

Turning Point in Deepwater

Tue, 01/22/2013 - 17:26

“Pemex’s exploration activities in 2012 had a heavy emphasis on deepwater,” says José Antonio Escalera Alcocer, Subdirector of Exploration at Pemex E&P. “It all goes back to our first efforts years ago to acquire seismic and regional studies to define the best prospective areas.” Once this strategy was in place, the company evaluated different basins in the deepwater Gulf of Mexico and decided to focus on five regions: the Catemaco folded belt, south subsalt provinces, the continuation of the Campeche Bay, the Cordilleras Mexicanas area, and the Perdido folded belt.

Pemex’s deepwater exploration activity in 2012 proved to be extremely successful by international standards: globally, exploration in deepwater usually averages one discovery for every three wells drilled. Thirteen years after the drilling of its first deepwater well, Pemex finally proved its critics wrong by discovering oil in deepwater. “The key factors in our success in deepwater were budget flexibility and the patience to allow the expertise to develop in order to execute our deepwater program,” says Carlos Morales Gil, Director of Pemex Exploration and Production. Pemex’s deepwater drilling success was based on the drilling of seven wells, which resulted in oil discoveries at Trion-1 and Supremus-1, a wet gas discovery at Kunah-1, where also the first delineation well was drilled, and non-producing wells Hux-1, Caxa-1, and Talipau-1. During the first years of Pemex’s deepwater exploration campaign, the company was only able to contract only one rig – Aker’s Ocean Worker – that allowed it to drill down to 1,000m water depth.

The exploration division first focused on Catemaco, where the company discovered a gas province. This made  the Catemaco folded belt the first targeted area where indications of hydrocarbons were found. “We went there and discovered a vast gas province, with the most representative field being Lakach, which is already in the development process,” says Morales Gil. The Ocean Worker – which was designed by Aker – also drilled successful gas-producing wells Noxal-1 and Lalail-1, while the Ocean Voyager – owned by Diamond Offshore and now turned into the Ocean Onyx – drilled gas and condensate producer, Leek-1. After Catemaco, Pemex’s exploration sights were set on testing some of the subsalt provinces in the south. “Even though we found hydrocarbons in those provinces, they were not yet ready for extraction,” Morales Gil details. “Catamat-1 constituted our first disappointment in deepwater.” Besides Catamat-1, drilled by Noble’s Max Smith rig, Pemex driled three more unsuccesful wells in the area: Chelem-1, Holok-1, and Kabilil-1. The first two were invaded by salt water, while the third one ended up being unproductive. In parallel, Pemex started drilling on another basin, Nox-Hux in the deepwater continuation of the Campeche Bay. The wells drilled there – Nab-1, which was drilled by Ocean Worker and Tamil-1, which was drilled by Ocean Voyager – were successful, with Pemex confirming heavy oil in the region.

In 2007, three additional rigs were contracted. The arrival of Centenario and Bicentenario in 2010, and of West Pegasus in 2011 allowed Pemex to venture down to 3,000m. This marked the start of testing a fourth deepwater area for hydrocarbons: Cordilleras Mexicanas. “We drilled three wells there: Caxa-1, Talipau-1, and Puskon-1,” Morales Gil says. “Puskon-1, which was the deepest well that Pemex had drilled in deepwater with a depth of 7,632m, turned out to be a very high-pressure well, and, although we discovered hydrocarbons there, the pressure made it extremely hard to evaluate them. Therefore, we decided to leave them out of short-term plans and come back in the future. Caxa-1 and Talipau-1, on the other hand, were a disappointment, but their shallow, tertiary formations might need additional geological surveys to check for the possibility of hydrocarbon content.”

Finally, the Pemex E&P division went to the long-anticipated Perdido folded belt, ready with rigs capable of drilling to 3,000m. After the seismic information was analyzed, Pemex decided where to drill first. “We proceeded to drill Trion-1 in the subsalt area of Perdido and we identified the presence of high quality hydrocarbons, in rocks with very good permeability and porosity in several geologic horizons,” Morales Gil describes. “After carrying out some drill stem tests, we celebrated our first discovery of light oil in deepwater, adding 350 to 500 million barrels to our 3P reserves.” Pemex then divided Perdido into two areas: the traditional Perdido folded belt and the subsalt area, 

which led to a new discovery. Supremus was supposed to be a trial well to obtain information for a better design of deeper wells, such as Maximino. “Surprisingly,” Morales says, “we also found some hydrocarbon accumulation in the Oligocene formation, which led to the discovery of around 125 million barrels of reserves.” The importance of these two wells was not only the unexpected discovery of oil reserves; it served as confirmation of the existence of a petroleum system that could add up to 13 billion barrels of oil, according to Pemex’s estimations. Today, Pemex has over 55 prospects identified in the area, which means that Mexico should have enough oil to remain a power in the global landscape for a good time to come, with the proper exploitation of its deepwater potential.

Between 2007 and 2010, Pemex spent around US$1.8 billion on deepwater exploration, accounting for roughly 24% of the company’s total exploration investment during the period. Much of this money was spent on acquiring seismic data and drilling wildcat wells. As a result of its ramped up seismic acquisition program, Pemex collected an average of between 15,000km2 and 20,000km2 of deepwater data per year during the period. This led to major exploration success during 2012 with four contracted deepwater drilling rigs and success rates above the average in the market. “So far, we have drilled 25 wells in deepwater, with a success rate of 55%, which is superior to the 33-35% of success that companies in the US part of the Gulf of Mexico have on average,” Morales Gil remarks. Even if the natural cycle would be to deviate back to the mean in terms of deepwater drilling success, the current success rate represents a big achievement for the Pemex’s drilling history.

WHAT’S NEXT IN DEEPWATER?

The next steps for Pemex lies in drilling delineation and development wells at all the oil and gas reservoirs that the company has already identified, while continuing exploration activity. “We will develop gas resources in Holok and Lakach with the semisubmersibles, and if we extend the exploration program north, we will contract some ships to perform exploration activities there,” Morales Gil says. “Our plan for the short term future will be to concentrate on two wells in the gas province – Piklis-1DL and Ahawbil-1 in the Labay area – and four wells in the north – Maximino-1, PEP-1, Basto-1, and Exploratus-1,” explains José Antonio Escalera Alcocer, Subdirector of Exploration at Pemex E&P. “We count on having Centenario, Bicentenario, West Pegasus, and the newly acquired Muralla IV to perform drilling tasks in the next few years. Muralla IV will first concentrate on less complex wells, complying with security best practices since it is a new semisubmersible, and two of the other three rigs will be operating in Perdido, with the possibility of acquiring another deepwater rig to operate there.” At the moment, drilling of deepwater wells Maximino-1, PEP-1 and Ahawbil-1 is already in progress.