In September 2009, Pemex announced that they had awarded their largest-ever 3D seismic campaign to international geophysical service provider CGGVeritas, now known as CGG. The contract specified that CGG acquire 75,000km2 of 3D seismic data starting in October 2009 and running until 2013. The high-end vessel Alizé, equipped with 12 Sercel Sentinel solid streamers fitted with Nautilus integrated streamer control devices, is towing one of the largest areal receiver arrays deployed in the industry. The Alizé has already acquired several large surveys in deepwater areas delivering high-quality data.
José Antonio Escalera Alcocer, Subdirector of Exploration at Pemex E&P division, has lobbied for the use of these technologies to increase the prospects of finding hydrocarbons in deepwater. “There are regions in the deepwater area that present saline accumulations in the seabed,” he explains. “New technologies have to be applied in order to thoroughly examine the geology of the salt layer on the seabed. Wide azimuth’s ability to expose the blurry underwater structures beneath those salt layers proved to be very eective in our discoveries at Perdido.”
In the past year, CGG has conducted double-density WAZ surveys in areas outside of deepwater, at Ayatsil, with its dedicated vessel. “The aim is to work in areas where seismic surveys have already been conducted, in order to intensify the resolution of the images,” explains Dominique Gehant, CGG’s Geomarket Director for Mexico. The resolution was improved through the use of CGG’s BroadSeis technology (see the article below).
“We are conducting a base survey to better characterize recently discovered extra heavy oil fields with the purpose of using the data to optimize production,” Gehant explains. “It is an industry first to acquire high-density, high-resolution, wide-azimuth data for field development purposes.” Pemex’s Exploration division manages this contract, but once the data is acquired, the development team that handles the Ayatsil field will oversee the data processing and reservoir characterization for the project.
“During the last few months, we have been holding meetings with our internal contracting area to maintain open contracts with the three leading seismic providers and gain the access to their new technologies,” Escalera Alcocer details. “The oil market is really dynamic: technologies move as companies change. Having open contracts with all the leaders – CGG, Western Geco, and PGS – allows us to freely request quotes on the dierent technologies that we deem appropriate for specific tasks.” The fact that Pemex now has a dedicated vessel, contracted from CGG through this model, to carry out wide-azimuth surveys helped in the feasibility of the project at Ayatsil. Gehant explains that in order to contract this work from scratch would have taken a lot longer than it took to simply move CGG’s surveying vessels into the region. This was key since the survey needed to be completed before production infrastructure was brought to the region, which makes seismic surveying a lot more complex.
This project has the potential to open the door to a brand new set of opportunities for seismic and geoscience companies: the chance to work with the Pemex on marine field development, and better characterize target reservoirs before infrastructure is developed. “Pemex is now much more open to new technologies than it was before, and they want to operate as a technology-driven player,” Gehant emphasizes. “Additionally, projects such as the double-density survey being conducted at Ayatsil have the potential to be carried out elsewhere. Pemex already sees the benefit of using the technology, where conventional techniques do not su·ce, both in shallow and deepwater.”
CGG is also a big believer in 4D surveys: carrying out multiple seismic surveys over a period of time in order to see the changes in the reservoir throughout the course of its producing life in order to analyze the field’s evolution. These technologies could enable Pemex to take its current experience at Ayatsil and turn to exploring unconventional fields to obtain a better understanding of the behavior of these reservoirs. “We already have some information on unconventional complexes at Tampico-Misantla, from which we have inferred the presence of shale oil prospects,” Escalera Alcocer says. With advanced technologies that enable a progressive look at geologic behavior, these reservoirs might be construed into opportunities for reserve replacement in the long-term, as deepwater is still being groomed to occupy the mid-term driver of production increase.