Arctic soil exploration performed by a research team at the initiative of Messoyakhaneftegaz altered the conception of permafrost formation history of the Gyda Peninsula (Yamal-Nenets Autonomous District). In recent years the hypothesis prevailing in the world of science has been that during the cold epochs of the Quatenary period (the modern period of the Earth history that began 2.5 million years ago) the peninsula lay under a thick ice sheet. However a detailed study of Messoyakha coring samples proved that 300 thousand years ago what is now Gyda was sea bottom. The research findings warrant a revision of the genesis of Russia’s Arctic territories.
Diving into Gyda
The Vostochno-Messoyakhskoe field is located in the Southern part of the Gyda peninsula within the territory of the Yamal-Nenets Autonomous District. The area remained undeveloped for decades due to extreme natural conditions and total absence of infrastructure near the oil zones. Gyda is an area of continuous permafrost. To extract oil there one must consider all the available drilling and construction options that will enable drilling operations on the frozen soil of sensitive Arctic tundra.
Information on Gyda permafrost is based predominantly on geological surveying data obtained in the 1970’s through the study of river bank deposits and geological engineering boreholes just 10-15 meters deep. This is why the structure of the peninsula’s cryolithic zone remained unexplored until recently. Prior to the development of the Messoyakhinskoye group of fields, oil producers had no experience operating on Gyda permafrost. Their search for a workable approach to extracting hard-to-recover reserves within the target territory required comprehensive research into icy soil strata. Geological analysis was performed on a coring sample from 100 meters depth (intact permafrost).
Drilling and Discoveries
Two out of five investigation wells at Messoyakha were drilled through the top of frost mounds – bulging areas of Gyda tundra where rock is pushed to the surface under pressure from permafrost. “And they hit the mark the first time: one borehole revealed an ice kernel at the base of the mound, and the other hit a mineralized water lens at the depth of 70 meters. Data was thus produced indicating the presence of an aquifer with gas-saturated brine lenses within the thickness of Gyda permafrost. What did we gain from the find? The primary benefit was high predictability of risks associated with gas seepage during well construction. Based on those results, drilling regulations were amended for mud fluid temperature and specialized well-kill equipment,” says Anna Kurchatova, Cand.Sc., Geology and Mineralogy, Geotechnical Monitoring Expert at Messoyakhaneftegaz.
Apart from applied data, geocryologists obtained evidence supporting the theoretical argument against the occurrence of glaciation in Southern Gyda. It was previously believed, in line with the glacier hypothesis, that in the period between 170 and 230 thousand years ago the present Gyda peninsula was under a thick ice sheet comparable to the one covering Greenland. But more recent research has proved that the Gyda area was initially a cold sea similar to Kara; as the sea subsided, deep soil freezing started. The peninsula’s permafrost is very young in comparison to Earth’s history – it has been there for just around 300 thousand years. Rock age dating became one of the fundamental scientific inferences made by the Gyda research team.
“Comparing research data from the so-called parametric wells, which are drilled for the specific purpose of exploring geological structure of reservoirs and permafrost columns, one can infer with confidence that the formation of Gyda permafrost in the cold climate epochs proceeded alongside neotectonic shifts triggered by global geologic events and restructuring of subsoil resources. This, in turn, predetermined vertical migration of hydrocarbons and contributed to the formation of the productive upper layer of modern arctic fields,” Kurchatova concludes.
Any deep borehole producing an undisturbed frozen corn is an extremely rare research object, and Messoyaha presented scientists with a wealth of artefacts from the depths of the centuries. Conceptualization of research data was done by representatives of the Institute of Petroleum Geology and Geophysics, the Moscow State University, and the Tyumen Research Center under the Russian Academy of Science, Siberian Branch.
To decipher the information, the scientists applied a broad range of methods from classical (using microfauna and plant pollen) to innovative ones such as optically stimulated luminescence – age of deposition was determined by the time when the mineral was last exposed to light. They also used the replica method to analyze even such unstable components as ice, entrapped gas and bacteria. The work culminated in an elaborate chronicle of Gyda’s upper Cenomanian deposits. This was the first ever detailed study of the peninsula subsoil.
In 2023 the research findings were discussed by industry experts in journals and conference sessions. “For more than half a century, the glacier theory has been competing with the marine theory in explaining the formation of ice sequence of Western Siberia and the Arctic. Proponents of the glacier theory revise the direction of glacial drift from time to time: now they claim the glaciers came from the Urals, then from Taimyr, and then from Arctic sea areas. But the recent research definitely speaks in favor of the marine theory, although without finalizing the geological record of Russia’s Extreme North. Geology is a very special discipline in that, while continuously enriching our understanding of planet Earth, it never gives the final answer to the question: How exactly did it happen? We need more facts and more evidence. Geological past may be as unpredictable as human history,” Kurchatova says.
Messoyaha and Permafrost
When organizing research work the industry experts aimed primarily to reduce the scope of possible risks associated with permafrost operations. Mineralized water lenses and gaseous cells discovered in the course of Gyda frozen core examination led them to conclude that there is high probability of gas shows during drilling operations. Initially this phenomenon was associated with marsh gas but now it is definitely attributed to vertical gas migration from productive strata. Subsurface ice and cryolithic zones are not impermeable. Permafrost breathes, it contains channels through which gas travels upward.
Detailed specification of frozen soil, its ice content and cross-section temperature distribution informed look-ahead calculations with the view to minimize the risk of tundra thawing around the production hole, says Sergey Ovchinnikov, Messoyakhaneftegaz Director for New Capacities.
“For the same purpose we maximize penetration rate when drilling the first series of wells using innovative digital and automated systems. In the next phase, the tophole is covered with heat insulating core shells (thermocases). The design which uses insulating material (polyurethane foam) filling the annulus maintains the target temperature inside the column within the wellhead area,” he explains.
Permafrost protection at the Vostochno-Messoyakhskoe field is also ensured by thermal soil stabilization systems placed under all key installations, including the pipeline transporting Messoyakha oil to the Zapolyarye – Purpe main pipeline. The 100 kilometer length of pressured oil pipeline is equipped with more than 5,500 heat stabilizers – piping systems with circulating liquid coolant that vaporizes at low temperature. By cooling the soil, such systems help prevent thermal effect on tundra and avoid deformation of structures.
