The second largest producing field in the world is the Cantarell complex in Mexico. It lies 85 kim from Ciudad del Carmen. The field was discovered in 1976 and put on production in 1979.
This is one of the geologically interesting oil fields because the producing formation was created when the Chicxulub meteor impacted the earth. The upper reservoir is a brecciated dolomite of Uppermost Cretaceous age. The breccia is from a shelf failure (underwater landslide) when the meteor hit. This 950 foot thick rubble became the reservoir for one of the biggest fields in the world. The lowermost part of the field is a Lower Cretaceous dolomitic limestone. The field is made up of a number of sub-fields or fault blocks. It has an overthrusted geological setting. These are Akal, Chac, Kutz and Nohoch. Akal was found first and the original well started producing at the rate of 34,000 barrels per day. A cross section of this field from Guzman and Marquez-Dominguez (2001, p. 346) is shown below:
See image: Akal cross section
Originally the field had 35 billion barrels of oil in place. Now, in place oil is not reserves. They expect to get around 50% of that oil out of the ground to market. The field reached an early peak in production of 1.1 million barrels per day in April of 1981 from 40 oil wells. By 1994 the production was down to 890,000 barrels of oil per day. At that time, cumulative production was 4.8 billion barrels. In 1995 it was producing 1 million barrels per day and the Mexican government decided to invest in that field to raise the production level. They built 26 new platforms, drilled lots of new wells and built the largest nitrogen extraction facility capable of injecting a billion cubic feet of nitrogen per day to maintain reservoir pressure. Doing this raised the oil production rate in 2001 to 2.2 million barrels per day. Today the field produces 2.1 million barrels.
To put this amount of production into perspectives, the largest field discovered in the US Gulf of Mexico will produce about 250,000 barrels per day. That field has about a billion barrels of reserves. If I were to find a field of that size, the company I worked for would probably make me president. For the world production, Cantarell represents 4 of the largest fields ever found in the US side of the Gulf. In 50 years of exploration in the US side of the Gulf of Mexico, only one one-billion-barrel oil field has been found. Bear this in mind as you read the rest.
A couple of weeks ago I ran into this from the oil industry rags I read. It is a chilling thought since this is the 2nd biggest producer of oil on earth. Ghawar produces 4.5 million bbl/day, Cantarell, 2.2 million bbl/day, Da Qing and Burgun around 1 million per day.
“Supergiant Cantarell continues to be the mainstay of Mexican oil production, with 2.1 MMb/d of output in 2003 up from 1.9 MMb/d in 2002. However, Cantarell is expected to decline rapidly over the next few years, falling as far as 1 MM b/d by 2008. This has given particular urgency to Pemex’s efforts to develop other fields and move into deepwater.” For now, Pemex’s best alternative project is the heavy-oil complex known as Ku-Maloob-Zaap, in Campeche Bay close to Cantarell. Output from this complex was 288,000 b/d in 2003 and is expected to rise to about 800,000 b/d by the end of the decade.” David Shields, “Pemex Ready to Drill in Deepwater Perdido Area,” Offshore, June 2004, p. 38
Even the largest fields we find offshore in the deepwater today only produce about 250,000 bbl/day. It will take about 4 of them to replace this decline in Cantarell.
And even the heavy oil field they mention won’t replace the loss of Cantarell by the end of the decade. And one must remember that all oil fields which are producing today, are in the process of declining.
The implications of this upcoming decline are tremendous to the world. This field produces half of what Ghawar does and it won’t be doing that much longer. The effect on the energy supply will be felt and there is no way for that not to happen. On Aug. 3, 2004, the OPEC president stated that OPEC has no more spare capacity. They are pumping all out and can’t satisfy the demand for oil. If fields like Cantarell begin declining, the problem of supplying the world with oil will only get worse.
References.
Alfredo E. Guzman, and Benjamin Marquez-Dominguez, “The Gulf of Mexico Basin South of the Border: The Petroleum Province of the Twenty-First Century,” in M. W. Downey , J. C. Threet and W. A. Morgan, editors, (Tulsa: AAPG, 2001).
E. Manceau, et al “Implementing Convection in a Reservoir Simulator: A Key Feature in Adequately Modeling the Exploitation of the Cantarell Complex,” SPE International Petroleum Conference and Exibition in Villahermosa, Mexico, Feb. 1-3, re 2000, SPE paper 59044
G. Murillo-Muneton et al, Stratigraphic Architecture and Sedimentology of hte Main Oil-Producing Stratigraphic Interval at the Cantarell Oil Field: the K/T Boundary Sedimentary Succession,” SPE International Petroleum Conference and Exhibition in Villahermosa,Feb. 10-12, 2002, SPE paper 74431
A. G. Rojas and A. R. Torres, “Akal Field (Cantarell Complex) Conditions of Exploration, Analysis, and Prediction,” SPE International Petroleum Conference and Exhibition in Veracruz, Mexico, Oct. 10-13, 1994. SPE paper 28714
Copyright 2004 G.R. Morton This can be freely distributed so long as no changes are made and no charges are made.
