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Insight

Enhanced Oil Recovery Technologies

Tue, 01/22/2013 - 14:18

During the last few years, Grupo Diavaz has taken pride in successfully applying enhanced oil recovery (EOR) technologies to stimulate production at several fields. Whether it has been through collaborations with other companies or by developing the technology in-house, the company has succeeded in its efforts to increase production in the mature fields of the Ébano-Pánuco-Cacalilao sector, almost doubling the amount of oil extracted from 2007 to 2012. With the experience at those fields, Luis Vázquez Sentíes, President of Grupo Diavaz, is trying to repeat his company’s success at Cantarell and Chicontepec.

While gas injection is the most commonly used EOR technology, Grupo Diavaz is also experimenting with other well injection techniques to stimulate production at each of the fields it is working on. “We are currently developing tests with steam, placing heating devices on diverse areas and monitoring the results,” says Vázquez Sentíes. His company is also focused on testing a new water injection technique in Chicontepec. “The results of our pilot project with Sinopec at Chicontepec have been excellent,” Vázquez Sentíes proudly emphasizes. “We’ve seen an increase from 3,000 b/d to 11,000 b/d at wells where we have tried our technology.”

The first step for Grupo Diavaz to undertake this new enterprise at Chicontepec was to become a certified operator under the Mexican Constitution. “It was a rough beginning for us, due to the lack of expertise we had,” says Vázquez Sentíes. “But after overcoming the initial hurdles, we introduced new techniques to the field, such as water routing. We started drilling at 900m depth first, since we wanted to get certainty of the condition of the well.” Once the reserves were located, water was injected and circulated horizontally to increase the pressure in the reservoir and thereby increase the production factor. Water was injected both to support the pressure of the reservoir and to push the oil out from the reservoir to the well. “This technique increased our extraction factor by 88% to 92%,” Vázquez Sentíes claims. “We began with a baseline of 16,000 barrels of recoverable reserves and managed to raise this number to 120,000 barrels. We still have the conviction that we could get up to 1 million barrels of reserves there.”

Grupo Diavaz, along with Sinopec, had to innovate on drilling techniques to overcome the harsher conditions of the fields at Chicontepec, compared to what the company was used to Ébano-Pánuco-Cacalilao. “Some of the wells that we drilled used to get flooded with water during the rainy season. At the beginning, we had no choice but to close them and stop production, since we did not have a solution to fight off the weather invasion,” Vazquez Sentíes explains. “We then decided to install small platforms at the well, so that the water could not flood the borehole during the rainy season of June and July.”

Secondary recovery techniques, such as water and gas injection, are crucial in enhancing production factors in challenging mature fields, but they can also work in helping to optimize production in fields where part of the reserves were overlooked. “Currently, Cantarell has two main issues,” Vázquez Sentíes says. “The first has to do with diluted oil. Since resources used to gush out of Cantarell with minimal effort, as soon as the easy oil has been produced, companies closed the well and moved on to the next one. The diluted oil remaining was left there, untouched, whereas in some countries, companies keep a profitable operation even when the oil is 95% composed of water.” Grupo Diavaz is trying to emulate what international companies do in other oil and gas markets and exploit the reservoirs in Cantarell that still have diluted oil reserves. “Our strategy is to associate with Norwegian companies to study the possibility of installing dehydrating facilities at our platforms to separate the water from the oil, filter it, deoxygenate it, apply biocides to it and return it to the sea, while we exploit the remaining 5% oil,” Vázquez Sentíes describes. These tests are being currently performed with an American company and Grupo Diavaz as the main technology provider.

“The second problem that we have observed in Cantarell is the result of years of nitrogen injection – another secondary oil recovery technique,” Vázquez Sentíes explains. “When nitrogen is injected into the well, more nitrogen is produced as a result. The inconvenience is that the amount of nitrogen that comes out is too much for companies to reacquire in full and reuse it. Technologies, such as nitrogen absorption equipment, which can be mounted at any platform, enable us to recover most of the nitrogen originally injected, remove the contaminated liquids from it, and use it again in the reinjection process.” Grupo Diavaz is looking to form joint ventures with companies that currently use these technologies, in order to achieve better results in production. Building on its offshore success, Grupo Diavaz is currently planning to use this technology onshore at Poza Rica. While companies such as Praxair already inject 10 times the amount of nitrogen, obtaining more penetration at a higher cost, the small-scale nitrogen absorption technology that Grupo Diavaz is trying to import seems to be cost-effective and reduces the waste in gas that comes from the original injection.