scholarly journals Forecast and assessment of hydrocarbon potential of cretaceous and jurassic deposits of the Kara Sea shelf based on the results of geological exploration

Author(s):  
A. D. Dzyublo ◽  
◽  
V. V. Maslov ◽  
V. V. Sidorov ◽  
O. A. Shnip ◽  
...  

According to the oil and geological zoning, the water area of the Kara Sea, including the Ob and Taz Bays, is located on the border of three oil and gas-bearing regions: Yamal, Gydan and Nadym-Purskaya, having different characteristics of oil and gas potential by section and by area. As a result of geological exploration carried out in the water area and on the adjacent land, a wide age range of oil and gas potential was revealed. Seven fields have been discovered in the waters of the Yuzhno-Kara NGO: six gas condensate fields in Cretaceous Cenomanian-Albian deposits and one oil and gas condensate field in Cretaceous and Jurassic deposits. Large gas condensate fields have been explored in the Ob and Taz bays in the Cenomanian-Alb-Apt complex. The water area of the lips is one of the most important areas in terms of the growth of economically viable natural gas resources. According to the research results, it has been established that the UV potential of the Jurassic and Lower Cretaceous complexes of the Ob and Taz Bays is characterized as highly promising. Keywords: Kara Sea; shelf; cretaceous and jurassic deposits.

2021 ◽  
Vol 247 ◽  
pp. 66-81
Author(s):  
Oleg Prishchepa ◽  
Ivan Borovikov ◽  
Evgenii Grokhotov

Comprehensive interpretation of the results for regional seismic operations and reinterpretation of archived seismic data, their correlation with the drilling data of more than 30 deep wells, including Severo-Novoborsk parametric well, made it possible to clarify the structural maps and thickness maps of all seismic facies structures developed in the territory and water area in the junction of the north of Izhma-Pechora depression and Malozemelsko-Kolguevsk monocline of Timan-Pechora oil and gas province. Data obtained were used at basin modeling in TemisFlow software in order to reconstruct the conditions of submersion and transformation of organic substance in potential oil and gas bearing formations. Modeling made it possible to get an idea of ​​the time and conditions for the formation of large zones of possible hydrocarbons accumulation, to establish space-time connections with possible sources of generation, to identify the directions of migration and on the basis of comparison with periods of intense generation, both from directly located within the operation area and outside them (taking into account possible migration), to identify zones of paleoaccumulation of oil and gas. Work performed made it possible to outline promising oil and gas accumulation zones and identify target objects for further exploration within the site with an ambiguous forecast and lack of industrial oil and gas potential.


Author(s):  
E. A. Lavrenova ◽  
Yu. V. Shcherbina ◽  
R. A. Mamedov

Background. Three prospective sedimentary complexes — Aptian-Upper Cretaceous, Paleogene and Neogene — are predicted in the waters of the Eastern Arctic seas. Here, the search for oil and gas is associated with harsh Arctic conditions at sea, as well as with high geological risks and significant expenditures under the conditions of poor knowledge of the region. In this regard, the localisation of prospecting drilling objects and the assessment of the geological risks of deposit discovery should be carried out.Aim. To assess geological risks and to determine the probability of discovering oil and gas fields, as well as to identify prospective areas for licensing and exploration in the water areas of the Eastern Arctic.Materials and methods. Structural and heat flow maps along with the results of geochemical analysis, as well as typical terrestrial sections were used as initial materials. Using the method of basin analysis, the modelling of generation-accumulation hydrocarbon systems (GAHS) and the quantitative assessment of its hydrocarbon potential in the Eastern Arctic water area was carried out. The assessment of geological risks and the probability of field discovery was performed using the conventional methodology widely applied by oil companies.Results. The GAHS modelling using a variation approach showed that, regardless of the kerogen type, with average values of Сorg in sediments, potential oil-and-gas source strata (OGSS) were capable of saturating the prospective objects with hydrocarbons. The “OGSS assessment” factor was determined as “encouraging” (0.7). Active geodynamic regime and the manifestation of several folding phases within the study area provided favourable conditions for the formation of anticlinaltraps in sedimentary basins. However, the cap rock quality rating was assessed as “neutral” (0.5). The overall risk for the “Trap assessment” factor was estimated based on the minimum criterion of 0.5.Conclusion. The most prospective areas recommended for licensing were selected, and the recommendations for further geological exploration work in these areas were given in order to clarify their hydrocarbon potential and reduce geological risks.


Author(s):  
A.D. Dzyublo ◽  
◽  
S.О. Borozdin ◽  
E.E. Altukhov ◽  
◽  
...  

Development of the Russian oil and gas fields in the Arctic requires ensuring industrial and environmental safety of conduct of the operations. Large and unique oil and gas condensate fields are discovered in the southern part of the Kara Sea. The Kamennomysskoye-Sea, Severo-Kamennomysskoye, Semakovskoye, Parusovoye, etc. gas condensate fields are located in the Ob Bay of the Kara Sea. The raw material base of the Severo-Obskoye gas condensate field, unique in terms of the reserves, will become the basis for future Arctic LNG projects. Based on the published data, the initial recoverable total hydrocarbon resources in the Ob and Taz bays are about seven billion tons. Active exploration and commissioning of the already discovered fields require the large volumes of well drilling in a freezing sea, the presence of permafrost, and gas hydrates. During construction of the wells and operation of the offshore ice-resistant oil and gas production platforms, it is required to ensure the disposal of drilling waste (cuttings) and domestic water. There are two technologies for waste disposal — injection into the reservoir or into the clay formations. The first one is used in onshore fields, the second one — on the shelf. Injection into a clay reservoir is successfully used in the Lunskoye gas field on the shelf of the Sakhalin island, and on the Prirazlomnoye oil field in the Pechora Sea. The possibility of using the method and the selection of a reservoir for injecting waste into it requires a geological justification, and the reservoir should ensure a stable injectivity of the required volume. The article presents the results of modeling the injection into the formation of drilling waste, and the waste of the household activities for the Kamennomysskoe-Sea gas condensate field. Calculation was made concerning the zone of absorption of the technological waste into the designed well of the offshore ice-resistant stationary platform. Formation allocation for waste injection was made according to the data of a complex of offshore wells geophysical studies. Three packs of sandy-argillaceous rocks with high reservoir properties were selected as the object of industrial waste disposal. Сalculation was carried out related to the radius of the spread of waste (effluent) in the target reservoir considering drilling and operation of twenty five wells, the construction of which is planned for five years. The results of modeling the process of pumping industrial waste of various types into an absorption well showed that the planned volumes can be successfully disposed of in the selected objects. This will allow to ensure functioning of the marine industry and its environmental safety.


1994 ◽  
Vol 34 (1) ◽  
pp. 674 ◽  
Author(s):  
Kevin Lanigan ◽  
Shane Hibbird ◽  
Sandy Menpes ◽  
John Torkington

Exploration over Roper Group outcrop in the McArthur Basin prompted Pacific Oil & Gas to investigate the petroleum potential of the Beetaloo Sub-basin, a 15 000 km2 Proterozoic depression concealed beneath Phanerozoic cover. Since 1989 drilling and seismic has identified a broadly flat-lying sequence with uplifted, eroded margins. A 3 500 m composite Proterozoic section consisting of three sandstone-to-mudstone sequences has been drilled. The lower two sequences comprise conformable units of the Mesoproterozoic upper Roper Group and unconformably overlying them is a previously unknown sequence comprising the informally labelled 'Jamison Sandstone' and 'Hayfield Mudstone', probably of Neoproterozoic age.Organic-rich intervals in the Roper Group mudstones range one to three per cent TOC in the Kyalla Member, and two to seven per cent TOC in the 'Middle' Velkerri Formation. Across most of the sub-basin the oil window lies within the Kyalla Member around 900–1350 m, while the 'Middle' Velkerri Formation is around 2 500 m and well into overmaturity, but may still have potential for gas. Potential reservoirs in the Bessie Creek, Moroak and 'Jamison' Sandstones, and in sandy units within the mudstones, are compromised by diagenesis, but porosities of up to 20 per cent and permeabilities of tens and rarely hundreds of millidarcies have been measured. Encouraging shows were observed in many of these intervals, and small quantities of oil and gas have been recovered in drill stem tests. With only a few targets drilled to date, this frontier area requires more exploration before its hydrocarbon potential can be adequately assessed.


Georesursy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 63-79
Author(s):  
Alina V. Mordasova ◽  
Antonina V. Stoupakova ◽  
Anna A. Suslova ◽  
Daria K. Ershova ◽  
Svetlana A. Sidorenko

Unique Leningradsky and Rusanovsky gascondensate fields in the Barrem-Cenomanian layer are discovered in the Kara Sea. Non-industrial accumulations of oil and gas have been discovered in the Lower Cretaceous sediments of the western part of the Barents Sea shelf. However, the structure and oil and gas potential of the Lower Cretaceous sediments of the Barents-Kara shelf remain unexplored. Based on the seismic-stratigraphic and cyclostratigraphic analysis, a regional geological model of the Lower Cretaceous deposits of the Barents-Kara shelf was created, the distribution area and the main stages of the accumulation of clinoforms were identified. As a result of a detailed analysis of the morphology of clinoform bodies, paleogeographic conditions were restored in the Early Cretaceous and a forecast of the distribution of sandy reservoirs was given


Author(s):  
H. I. Rudko ◽  
V. V. Sobol

Energy independence is an important component of sustainable development and security of the state. Ukraine has a great hydrocarbon potential of the subsoil, which is why the priority objective is a search and exploration of new deposits of hydrocarbon raw materials. One of the important directions for increase of potential resources and reserves of oil and gas is the development of large deep (over 4500–5000 m) deposits, as hydrocarbon reserves at small and medium depths are quite depleted in many regions. For a long time, hydrocarbon reservoirs in basement rocks were underestimated during geological exploration works. Obtained results indicate that new concepts of the formation of hydrocarbon deposits can dramatically change the system of oil production, methods of prospecting and development of deposits. It is important to assess possible oil-and-gas-bearing capacity of sediments and rocks of the basement by identifying prospective areas of hydrocarbon deposits, including in the rocks of the crystalline basement. In Ukraine, main prospects of discovery of oil and gas deposits at great depths are associated nowadays with the Dnieper-Donets Rift (DDR). Deposits with accumulations of hydrocarbons at depths of more than 5000 m are concentrated in the main oil-and-gas-bearing areas of the Rift that coincide with the central paraxial and marginal zones of the graben. It was in the central segment of the DDR that the main regularities of oil-and-gas-bearing capacity of deep-lying geological formations were first discovered: secondary nature of reservoirs, discovery of the phenomenon of supercollectors and associated huge debits. It is relevant and promising to study the process of recovery/replenishment of gas reserves by the example of deposits that are at the final stage of development.


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