scholarly journals Paleoкarst, hydrothermal karst and karst reservoirs of the Franian reefs of the Rybkinsky group

Georesursy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 15-28
Author(s):  
Aleksandr P. Vilesov ◽  
Kseniya N. Chertina

More than 20 isolated reefs of the Rybkinsky group were discovered in 2015-2018 in the eastern part of the Rubezhinsky Trough, west of the Sol-Iletsky Arch (Orenburg region; southern part of Volga-Ural Oil and Gas Province), thanks to the use of seismic surveys 3D and exploration drilling. The interval of the stratigraphic distribution of the reefs encompasses Domanikian, Rechitskian and Voronezhian Horizons (=Regional Stages) of the Franian Stage of Upper Devonian. The reefs are cased and overlapped by carbonate-terrigene-clay deposits of the Kolganian Formation that form the seal. High-amplitude oil fields (up to 150 m high) are related to the bodies of reefs. Reefs developed under conditions of significant changes in sea level caused by both eustatic fluctuations and regional tectonics. Actual data on features of surface and deep karst in different reefs of the Rybkinsky group are given. Three karst epochs are allocated: 1) late Domanikian; 2) late Rechitskian; 3) late Voronezhian. Evidences of the post-franian hydrothermal karst in the reefs are presented. Reservoirs formed as a result of karst are characterized by high complexity of pore space. Reef reservoirs have a scale permeability effect that is necessary to consider in hydrocarbon reserve calculations.

Author(s):  
B.M. Das ◽  
D. Dutta

Nanotechnology encompasses the science and technology of objects with sizes ranging from 1 nm to 100 nm. Today, exploration and production from conventional oil and gas wells have reached a stage of depletion. Newer technologies have been developed to address this problem. Maximum oil production at a minimum cost is currently a huge challenge. This paper reviews nanotechnology applications in the oil and gas production sector, including in the fields of exploration, drilling, production, and waste management in oil fields, as well as their environmental concerns. The paper reviews experimental observations carried out by various researchers in these fields. The effect of various nanoparticles, such as titanium oxide, magnesium oxide, zinc oxide, copper oxide, and carbon nanotubes in drilling fluids and silica nanoparticles in enhanced oil recovery, has been observed and studied. This paper gives a detailed review of the benefits of nanotechnology in oil exploration and production. The fusion of nanotechnology and petroleum technology can result in great benefits. The physics and chemistry of nanoparticles and nanostructures are very new to petroleum technology. Due to the greater risk associated with adapting new technology, nanotechnology has been slow to gain widespread acceptance in the oil and gas industries. However, the current economic conditions have become a driving force for newer technologies.


2011 ◽  
Vol 51 (1) ◽  
pp. 147
Author(s):  
Ciaran Lavin ◽  
Terry Walker ◽  
Yvette Knowles

An uncertain global economy, offset by strong commodity prices, provided the backdrop to a subdued yet solid level of exploration activity in 2010. The major loci of activity in the Australian oil and gas industry were the Exmouth Plateau, where exploration for conventional gas in support of LNG projects was the primary driver, and the Bowen/Surat Basin, where coal seam gas (CSG) for LNG was the main target. Onshore permit awards dominated new licensing in 2010, with 31 exploration permits awarded over an area of 190,000 km2. The majority of these permits are focused on unconventional gas exploration. Conversely only 14 exploration permits (30,000 km) were awarded offshore, all in northwest Australia. This historically low level can be related to an already extensive coverage of existing permits in the offshore petroleum provinces and delays in the announcement of acreage awards from the 2009(II) acreage release. Twenty-nine 2D seismic surveys were started in 2010, with three still active at the end of the year. Once completed, the 2010 surveys will total nearly 37,000 km of data, with 76% offshore. Twenty-one 3D seismic surveys commenced in 2010, with six still active at year end. The 2010 surveys will ultimately comprise approximately 29,000 km2 of data, with 95% offshore. Northwest Australia dominated seismic activities. Exploration drilling for conventional hydrocarbon resources was relatively subdued in 2010, with 63 wells spudded, compared to 92 wells in 2008 and 74 in 2009. Of the 49 wildcat wells where results are known, 51% reported hydrocarbon discoveries. This was a little less than the 57% in 2009 and up on the 39% in 2008. The discoveries were distributed across most of the traditional petroleum provinces. High levels of CSG drilling continued in 2010, exceeding 2008 activity but less than that of 2009. At least 648 CSG wells were spudded in 2010, mostly in the new heartland plays of the Bowen/Surat, Gunnedah and Clarence-Moreton basins. This compares with more than 600 CSG wells drilled in 2008 and more than 900 in 2009. The first dedicated Australian shale gas exploration drilling took place in 2010. Emerging shale plays in the Cooper and Perth basins were tested.


Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 260 ◽  
Author(s):  
Yang Wu ◽  
Yixin Zhao ◽  
Peng Li

Capillary imbibition in unsaturated rocks is important for the exploitation of tight reservoirs, such as oil and gas reservoirs. However, the physical properties of natural rocks tend to be relatively uneven, mainly in the heterogeneity of material composition and pore space. Reservoir heterogeneity is an important factor affecting the exploitation of oil fields and other reservoirs, which can be evaluated by the pore structure tortuosity fractal dimension DT of rock. The greater the value of DT, the stronger the heterogeneity of sandstone. Two types of sandstone with high and low permeability were selected to study the effect of heterogeneity on the imbibition behavior by using high-resolution X-ray imaging and neutron radiography. Quantitative results of the wetting front position for each specimen were extracted from the neutron images. The wetting front advanced linearly with the power index of time t1/(2DT). Different values of DT were selected to estimate and discuss the effect of the heterogeneity on sorptivity. A modified L-W equation was employed to predict the sorptivity. Comparing with the experimental results, the heterogeneity plays a significant role in determining the sorptivity. The modified model provides a reference for the prediction of the sorptivity of the same types of sandstones studied in this paper.


2013 ◽  
Vol 53 (1) ◽  
pp. 141
Author(s):  
Deidre Brooks

The Australian exploration landscape experienced an escalation of unconventional activity in 2012. Drilling targeting shale oil and gas, basin-centred tight gas, and coal gas is on the increase compared to previous years. Drilling for onshore oil and large offshore gas continued to be a staple activity for the year although, in general, offshore, the number of wells drilled is continuing to decline, in line with previous years. A number of very large 3D seismic surveys were acquired in 2012 and this is hoped to provide many future drilling targets. Within Australia, 19 new offshore conventional petroleum exploration permits were awarded within the Commonwealth jurisdiction (compared to 24 in 2011), of which 15 are located in WA, two in Victoria, one in NT, and one in the Territory of Ashmore and Cartier Islands (NT). Onshore exploration tenures awarded in 2012 included four in WA, 14 in NT, six in Queensland, and nine conventional and six geothermal in SA. At least 25 3D and six 2D seismic surveys were acquired offshore in 2012, including some very large 3D marine surveys, the largest covering an area of 12,417 km2. Onshore seismic activity was highest in Queensland and SA where 33 and 11 surveys were acquired, respectively. Offshore, 21 conventional petroleum exploration wells were drilled during the year, which resulted in 11 announced discoveries. Two exploration wells, which were spudded late in 2011, were announced as discoveries early in 2012. Five wells, which were spudded in 2012, were still drilling at year end. This equates to a better than 50% technical success rate for offshore exploration drilling for all well results known at year end. All but two of these wells were located in WA waters, the others being located in NT and Victoria. Australia-wide onshore drilling was more active than in 2011 and, as is reflected in the seismic activity, the most wells (1,048) were drilled in Queensland (dominated by CSG drilling), followed by SA (77).


2019 ◽  
Vol 10 (4) ◽  
pp. 1011-1027
Author(s):  
A. R. Kurchikov ◽  
A. G. Plavnik ◽  
D. A. Kurchikov

This paper discusses the productive beds of the Urna and Ust‐Tegus oil fields (West Siberia, Russian) and permeability and capacity properties that are influenced by geodynamic processes. Strong tectonic processes, accompanied by periodic magma intrusions, produced numerous fractures and faults in the Jurassic sediments, which act as conduits for groundwater flows, and thus led to the hydrothermal alteration of rocks and changes in the pore space. The data presented in the paper testify to the manifestation of these processes in the modern hydrogeochemical and geothermal conditions of the Jurassic‐Cretaceous sediments within the two oil fields and their vicinity. The petrophysical studies of the core samples and the hydrodynamic studies in the wells confirm that the reservoir properties of the productive strata are considerably heterogeneous. Despite the significant effect of the geodynamic factors, the analysis of the tracer data has not revealed any apparent spatial consistency of the presence (or absence) of a hydrodynamic connection between the wells and the locations of fractured and dynamically stressed zones. In our study, we have proposed and tested a method based on the analysis of morphotectonic features detectable in the depth maps of reference surfaces. This method is a useful additional tool for discovering and analyzing the relationships between the tectonic and hydrodynamic conditions of oil and gas fields.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4570
Author(s):  
Aman Turakhanov ◽  
Albina Tsyshkova ◽  
Elena Mukhina ◽  
Evgeny Popov ◽  
Darya Kalacheva ◽  
...  

In situ shale or kerogen oil production is a promising approach to developing vast oil shale resources and increasing world energy demand. In this study, cyclic subcritical water injection in oil shale was investigated in laboratory conditions as a method for in situ oil shale retorting. Fifteen non-extracted oil shale samples from Bazhenov Formation in Russia (98 °C and 23.5 MPa reservoir conditions) were hydrothermally treated at 350 °C and in a 25 MPa semi-open system during 50 h in the cyclic regime. The influence of the artificial maturation on geochemical parameters, elastic and microstructural properties was studied. Rock-Eval pyrolysis of non-extracted and extracted oil shale samples before and after hydrothermal exposure and SARA analysis were employed to analyze bitumen and kerogen transformation to mobile hydrocarbons and immobile char. X-ray computed microtomography (XMT) was performed to characterize the microstructural properties of pore space. The results demonstrated significant porosity, specific pore surface area increase, and the appearance of microfractures in organic-rich layers. Acoustic measurements were carried out to estimate the alteration of elastic properties due to hydrothermal treatment. Both Young’s modulus and Poisson’s ratio decreased due to kerogen transformation to heavy oil and bitumen, which remain trapped before further oil and gas generation, and expulsion occurs. Ultimately, a developed kinetic model was applied to match kerogen and bitumen transformation with liquid and gas hydrocarbons production. The nonlinear least-squares optimization problem was solved during the integration of the system of differential equations to match produced hydrocarbons with pyrolysis derived kerogen and bitumen decomposition.


2021 ◽  
Vol 25 (11) ◽  
pp. 4-11
Author(s):  
K.L. Chertes ◽  
O.V. Tupitsyna ◽  
V.N. Pystin ◽  
G.G. Gilaev ◽  
N.I. Shestakov ◽  
...  

The features of maintaining large-capacity waste from oil and gas fields that are suitable for recycling into secondary products are considered. A step-by-step system for selecting and justifying a waste is proposed taking into account the development of the deposit, its natural and manmade features, as well as the selected stages of operation. Pieces of technological schemes of waste preparation are given, as well as the design of the waste preparation complex for disposal constructed at one of the largest oil fields of the Samara region.


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