Microclinoform structure of the BT<sub>10</sub> horizon as a factor controlling the formation of gas fields in the southeastern part of the Yamalo-Nenets Autonomous Okrug

Abstract

The microclinoform model of the Neocomian shelf reservoirs is becoming more and more supported by practicing geologists, since it allows to effectively address the problems arising in the development of complex reservoirs. According to modern concepts, the microclinoform structure is due to the intense progradation of delta complexes during periods of forced regression. The article demonstrates the effectiveness of the microclinoform concept in building a geological model of an accumulation in BT10 horizon of Zapadno-Chaselsky field, which is located in the southeastern part of the Russko-Chaselsky large swell in the southeast of the Yamalo-Nenets Autonomous Okrug. The microclinoform structure of the target was mapped based on the data volume of the second derivative of the wave field, which is more sensitive to changes in thicknesses, and porosities of sand reservoirs. As a result of comprehensive studies, correlation profiles and a GDE map of stratigraphic unconformity (top of BT10) were built reflecting the microclinoform structure of the target. The results were used to build a model of a gas reservoir and estimate its reserves. Hydrocarbon discoveries have already been made in the BT group of reservoirs at Zapadno-Chaselsky field and neighboring Yuzhno-Russkoye field that improves the potential of this interval within the southeastern part of the Yamalo-Nenets Autonomous Okrug. This poses the task of its more detailed study based on the microclinoform concept.