Geoffrey Slater, Dmitry Krivobokov, Michael Brannan, Houston

Оn September 25, 2017, LUKOIL was being awarded the contract for the Block 12 in the Sureste Basin offshore Campeche, one of Mexico’s regions, with state participation in profits of 75% and a one well commitment.

LUKOIL won Block 12 early this summer, when Mexico’s National Hydrocarbons Commission (CNH) held its second shallow water licensing round for 15 offshore blocks located in that country’s portion of the Gulf of Mexico. IOCs had demonstrated considerable interest in the opportunities therein after recent discoveries by ENI on the Amoca Block.

The successful bid marked months of tireless efforts Houston-based LUKOIL International Upstream West (LIUW) “geolog y detectives,” who analyzed geological, geophysical and engineering data purchased from the CNH as a part their entry qualification, to form an idea of what mysteries lie hidden below the ocean surface. This is their story.

Why Block 12?

Members of Business development team of LIUW have extensive experience in oil and gas exploration in the US portion of the Gulf of Mexico. It helps that the newly opened basins in Mexico’s section of the Gulf, from Perdido to Campeche, share the same petroleum system as up north. Based on the experts’ experience, Block 12 in the Sureste basin stood out as having the same prospects as discoveries made 40 years ago in the shallow waters of Texas and Louisiana.

Block 12 is 521 sq. km. and has a water depth of between 100 and 500 meters. LUKOIL’s geologists had the advantage of a reliable 3D seismic dataset due to the fact that the Block has no overlying salt, meaning the area was easier to map and also an easier target for exploration drilling.

By the time LUKOIL won the bid, state-owned Pemex had already drilled two exploratory wells in search of deep carbonate reservoirs from the Cretaceous Period. By helping scientists peer back into the time of the dinosaurs, both wells had confirmed that source rock existed in the Block and that oil and gas had migrated into the overlying Tertiary sandstone deposits of the later Pliocene and Miocene ages.

Pemex had identified a layer of sand from the Pliocene period and determined it to be oil bearing. This evidence, combined with structural similarities to similar reservoirs discovered offshore the US decades earlier, convinced the Houston team that Block 12 was where they should search for oil. But this was only the beginning.

The Sweetness Cube

LIUW’s geoscientists understood that the risk of not finding sufficient quantity of sand reservoirs was high. Senior Geophysicist Ron Barrow created a 3D seismic model that enhanced seismic amplitudes to help better understand sand deposition in the area.

“We recognized there were several closures in Block 12 with good potential. The weak point in the analysis, as we started refining our work, was demonstrating the potential of reservoir quality sands within these structures,” said Barrow. “In previous areas I had worked, we had generated an attribute from the seismic data generally referred to as “Sweetness.” Subsequent wells drilled in these areas indicated that the “Sweetness” attribute had successfully identified the presence of reservoir sands. Using the “Sweetness” attribute, we were able to identify potential reservoirs in the Pliocene and Upper Miocene geological time periods over some of the structures in Block 12.”

Team work

LIUW’s geoscientists continued to refine this concept and produced a series of structure maps to better define the extent of prospective reservoirs. Senior Reserves Geologist Nikolai Raevski used a Monte Carlo model, familiar to any math scholar, to capture the distribution of potential oil resources that could be trapped in Block 12’s 12B West and East sections. This was used to create so-called Productivity Indices (PIs) for all reservoirs identified on the maps.

Senior Reservoir Engineer Charlene Chuang and Development Engineer Dmitry Krivobokov, used the PIs to build production profiles and the number of wells required for each reservoir. Complete development designs, well designs and cost analysis were developed as inputs for the final economic calculations, in collaboration with LIUW’s Drilling and Development teams. Those were completed by Development Drilling Engineer Andrey Zdvizhkov, and Principal Facilities Engineer Michael Brannan, who provided drilling estimates and facilities costs and design, respectively.

Geoffrey Slater:

“This success to win Block 12 came as the result of professional experience, long hours of dedicated work and team collaboration. The ultimate test, however, will come with the drilling of LUKOIL’s first exploratory well offshore Mexico in 2019. We will then find out if our geological detective work was accurate. The recent discovery by Talos south-west of Block 12 in a similar trap is evidence that we are looking in the right place. We want to bring a great success to LUKOIL”.

Geoffrey Slater - Director for Business Development in Western Hemisphere, LIUW

Dmitry Krivobokov - Development Engineer, LIUW

Michael Brannan - Principal Facilities Engineer, LIUW