Moscow, July 10, 2020 - Specialists of Central Geophysical Expedition (CGE, a subsidiary of RosGeo) within the framework of the project "Geological survey of Nerutino zone oil and gas potential in Western Siberia" under the contract with Gazpromneft-GEO analyzed the geological and geophysical information on subsurface resources in the territory Nadym and Purovo regions of Yamalo-Nenets Autonomous District, which had been specified as a priority area at the regional stage of the work.

CGE performed the assessment of the resource base and ranking of promising structures in the subsurface area with identification of those of the most promising nature for detailed geological and economic estimation. The completed works resulted in the findings that Nerutino zone has a hydrocarbon potential and drafting of the program for its further surveys. The results might be used for assessment of the hydrocarbon resources and selection of areas for the geological prospecting.

“The specific feature of the competed work is the fact that input 2D and 3D seismic data had been collected by the field expeditions for 35 years - from 1974 to 2009 - using various techniques of field surveys, processed by different methods and with application of different software - Dr. Sergey Kirillov, Managing Director of Central Geophysical Expedition, said. - Normalized to a common level of amplitudes and interlinked 2D profiles and 3D cubes enabled the successful performance of further interpretation”.

In the framework of the project the specialists of CGE interpreted 35000 linear km of 2D seismic data (948 profiles) and about 6500 km2 of 3D seismic data (9 cubes). The project team summarized the geological and geophysical data of Nerutino zone using the original methodological techniques, software and hardware, integrated analysis of heterogeneous geological and geophysical information, and mapped the hydrocarbon traps in the Jurassic-Neocomian sediments.

Background:

Along with bringing of all areal seismic data to a uniform format the well data have also been restored to a qualitatively new level. The restoration of missed well logging intervals resulted in enabling to assess the influence of the collector properties, density and saturation character of petroelastic rocks. All GIS data available for both the site of the work performance and adjacent territory were used for correlation and calculation of a huge number of parameters. Seven reference seismic horizons were stratified in all areas of drilling.

The most promising part of the section, the clinoform Neocomian layes, are traced the hollow overlying reflecting horizons of Lower Cretaceous . 13 clinoforms were mapped and stratified in the course of detailed study of the Achimov sequence. The elaborated tectonic model supplemented the structure of the Nadym-Tazov sineclysa and Nerutino zone.

The specialists of CGE experts have developed a conceptual sedimentational model of Neocomian depositional sequence based on the principles of sequence stratigraphy. This became the basis for study of the development history of the clinoforms, detailed survey of the model of the depositional sequences (cyclites), and elaboration of a unique technique for mapping of Achimov sequence roof by transition points of the slope deposits (reflections) into accumulation section, outlining of the zones of the fascies association development zones main, which location is confirmed by sedimentation core studies, as well as by analysis of electric-logging diagrams. The obtained materials allowed to trace the main directions for the material intake during its development for each of the identified clinicyclites, identify the deposition accumulation centers, etc.

In addition, to identify the promising clinoforms the experts used an unusual method for seismic-geological information, elaboration of a pseudo-cube on the basis of 2D seismic surveys. In addition, they outlined and collerated the roofs of the dynamic anomalies in the hydrocarbon-potential sandstones. The summarizing results of the work with the dynamic attributes of the cubes and pseudo-cubes allowed to reveal the anomalies that substantiated the promising clino-cyclites.

Reference:

JSC Central Geophysical Expedition is a service company with over 50 years of practical experience in the field of processing and interpretation of seismic and geophysical materials, elaboration of geological deposit models. It provides the high-quality performance of a full range of geological, geophysical and field surveys in accordance with international standards. CGE was established by the Ministry of Oil Industry of the USSR in 1967 as a research and production center for management of the process on translation of geophysics data into the digital recording and processing.

RosGeo is a Russian multi-disciplinary geological holding that carries out a full range of services related to geological exploration: from regional surveys to parametric drilling and monitoring of subsoil conditions. The holding company boasts a unique expertise, particularly in marine geology and shelf operations. A total of more than 1,000 fields and deposits have been discovered by the holding’s companies, including major hydrocarbon and solid mineral deposits and fields. RosGeo is a fully state-owned company.