Stratigraphic mapping of sedimentary formations in southern Ontario by ground electromagnetic methods

Geophysics ◽  
1990 ◽  
Vol 55 (9) ◽  
pp. 1148-1157 ◽  
Author(s):  
Ajit K. Sinha
Keyword(s):  
Oil And Gas ◽  
Structural Features ◽  
Southern Ontario ◽  
Transient Electromagnetic ◽  
Electromagnetic Methods ◽  
Geological Information ◽  
Survey Results ◽  
Multifrequency System ◽  
The Village ◽  
Depth Of Investigation

Multifrequency and transient electromagnetic (EM) soundings were done at several locations in southern Ontario to evaluate the possibility of stratigraphic mapping of gently dipping sedimentary formations by ground EM techniques. The possibility of detecting structural features such as folds, faults, and grabens in the formations was also explored. The two EM techniques were used to map a buried river valley near the village of Copetown, about 75 km southwest of Toronto. The valley, buried under fairly resistive glacial till and dolomite formations was mapped at depths ranging from 100 to 200 m. The interpreted shape and depth of the valley agreed well with information from a high resolution seismic reflection survey and data from wells penetrating the bedrock. Transient EM (TEM) data, using square transmitter loops with side dimensions comparable to the transmitter‐receiver separation for the multifrequency system, was found to be less affected by the presence of shallow conductors and lateral inhomogeneities than the multifrequency data, and had greater depth of investigation. TEM soundings were made on five additional profiles in the area. Lithologic logs from old oil and gas wells located near the profiles provided information for comparison with EM sounding interpretations. The depths to various dolomite, shale, and limestone formations interpreted from EM data agreed well with drillhole information. The EM soundings also detected structures in the Paleozoic formations such as faults and folds that were not previously known. The soundings confirmed the existence of a graben at one site at a depth of 100 m, which was postulated from logs from a cluster of closely spaced drillholes by geologists. The survey results indicated that EM sounding methods can be used for stratigraphic mapping in areas where detailed geological information is unavailable either because the bedrock is concealed by overburden, or when drillholes are sparsely distributed.

EVALUATION OF HYDROCARBON SEEPAGE IN THE GREAT AUSTRALIAN BIGHT

2002 ◽  
Vol 42 (1) ◽  
pp. 371 ◽  
Author(s):  
H.I.M. Struckmeyer ◽  
A.K. Williams ◽  
R. Cowley ◽  
J.M. Totterdell ◽  
G. Lawrence ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Liquid Hydrocarbon ◽  
Structural Features ◽  
Long Distance ◽  
Seal Failure ◽  
Late Tertiary ◽  
Geological Information ◽  
Sar Data ◽  
Active Tectonism ◽  
Great Australian Bight

The regional assessment of hydrocarbon seepage is built around a combination of Radarsat and ERS Synthetic Aperture Radar (SAR) data, acquired during 1998 and 1999, as part of a collaborative project between Geoscience Australia, Nigel Press Associates, Radarsat International and AUSLIG (specifically the Australian Centre for Remote Sensing). In total, 55 Radarsat Wide 1 Beam Mode scenes and one ERS scene from the Great Australian Bight (GAB) region were analysed. The data were integrated with regional geological information, and other hydrocarbon migration and seepage indicators such as reprocessed and reinterpreted legacy Airborne Laser Fluorosensor (ALF) data, to provide an assessment of the possible charge characteristics of the region.The results of the study suggest that active, though areally restricted, liquid hydrocarbon seepage is occurring within the Bight Basin. The majority of seepage slicks occur along the outer margin of the major depocentre, the Ceduna Sub-basin, in areas where significant Late Tertiary to Recent faulting extends to the seafloor. Very little evidence of seepage was observed on the SAR data above the main depocentre, which is an area of minimal Late Tertiary to Recent faulting. Reprocessed ALF data reveal three main areas with relatively dense fluors. Although they are not directly coincident with locations of seepage interpreted from SAR data, their distribution support the pattern of preferred leakage along the basin margins.Integration of regional geological models with the results of this study suggests that structural features related to active tectonism have focused laterally migrating hydrocarbons to produce active seepage at specific locations in the basin. Where these features are absent, seepage may be passive and/or be governed by long distance migration to points of seal failure. Together with oil and gas shows in exploration wells, observations from this study provide further evidence that liquid hydrocarbons have been generated in the Great Australian Bight.

Significance of Mineralogical and Lithologic-Petrographical Rank in the Ranking of Geological Information

2020 ◽  
Vol 42 (4) ◽  
pp. 33-49
Author(s):  
O.V. CHEPIZHKO ◽  
V.V. YANKO ◽  
V.M. KADURIN ◽  
I.M. NAUMKO ◽  
S.M. SHATALIN
Keyword(s):  
Fluid Flow ◽  
Black Sea ◽  
Bottom Sediments ◽  
Oil And Gas ◽  
Sedimentary Cover ◽  
Geochemical Characteristics ◽  
The Black Sea ◽  
Flow Parameters ◽  
Geochemical Parameters ◽  
Geological Information

For the first time the importance of mineralogical and lithological-petrographical ranks in the line of geological information ranks is substantiated for implementation of long-term forecasts, standard and non-standard approaches to research of physical and geochemical parameters as a basis of creation of complex system of forecast criteria and prospecting indicators of hydrocarbons within the sedimentary cover of Black sea based on the theory of global fluid-flows derivation. These criteria have different sensitivity to the object (hydrocarbon deposits) and are therefore ranked. The ranking determined the following parameters: 1) seismic data within the object, obtained by the method of deep seismic sounding, RWM SDP; 2) parameters of tectono-geodynamic structures; 3) the main characteristics of sedimentary cover and bedrock; 4) geochemical characteristics; 5) parameters of mineral complexes and fluid inclusions in mineral neoformations; 6) the value of the distribution of meiobenthos. Based on modern views of oil and gas geology, structural-tectonic and lithological-facies criteria are among the main ones. The study of the mineralogical component of sediments is made with using mineralogical, thermobarogeochemical and X-ray spectral methods. Fixation of anomalies of fluid flow at the bottom of the Black Sea as to the distribution of abiotic parameters in order to assess the prospects of oil and gas is determined by structural and tectonic features and high permeability of fluid flow; parameters of mineral complexes (minerals, facies) and genetic connections; heterogeneity of geochemical characteristics of bottom sediments; the presence of hydrocarbon inclusions in authigenic minerals of bottom sediments.

Minerals as an object of accounting and economic security of the oil and gas company implementing the production sharing agreement

2020 ◽  
Vol 23 (11) ◽  
pp. 1291-1312
Author(s):  
N.V. Zyleva
Keyword(s):  
Oil And Gas ◽  
Economic Security ◽  
The State ◽  
Professional Judgment ◽  
Production Sharing ◽  
Security Service ◽  
Geological Information ◽  
Oil And Gas Companies ◽  
Mineral Reserves ◽  
Economic Risks

Subject. This article discusses the practice of ensuring the economic security of oil and gas companies operating under the terms of production sharing agreements, where minerals are the object of security. Objectives. The article aims to justify the need to apply professional judgment in the organization of reliable accounting of minerals, explored and extracted under the terms of the production sharing agreement implementation, to avoid various risks to the entity's economic security. Methods. For the study, I used the methods of deduction and modeling. Results. The article presents proposals to arrange accounting of intangible exploration assets (geological information on mineral reserves) and finished products (the part of the extracted minerals owned by the investor and the part owned by the State). Conclusions. As strategic minerals, oil and gas are the targets of various economic risks. Professionals familiar with the specifics of accounting operations in the implementation of the production sharing agreement should be prepared to prevent these risks. The results obtained can be used to design accounting policies and develop local regulations on the tasks and functions of the economic security service of the organization implementing the production sharing agreement.

scholarly journals One-dimensional constrained inversion study of TEM and application in coal goafs’ detection

2020 ◽  
Vol 12 (1) ◽  
pp. 1533-1540
Author(s):  
Si Yuanlei ◽  
Li Maofei ◽  
Liu Yaoning ◽  
Guo Weihong
Keyword(s):  
Least Squares ◽  
Least Squares Method ◽  
Data Interpretation ◽  
Volume Effect ◽  
Underground Space ◽  
Attenuation Curve ◽  
One Dimensional ◽  
Transient Electromagnetic ◽  
Geological Conditions ◽  
Geological Information

AbstractTransient electromagnetic method (TEM) is often used in urban underground space exploration and field geological resource detection. Inversion is the most important step in data interpretation. Because of the volume effect of the TEM, the inversion results are usually multi-solvable. To reduce the multi-solvability of inversion, the constrained inversion of TEM has been studied using the least squares method. The inversion trials were performed using two three-layer theoretical geological models and one four-layer theoretical geological model. The results show that one-dimensional least squares constrained inversion is faster and more effective than unconstrained inversion. The induced electromotive force attenuation curves of the inversion model indicate that the same attenuation curve may be used for different geological conditions. Therefore, constrained inversion using known geological information can more accurately reflect the underground geological information.

The use and misuse of apparent resistivity in electromagnetic methods

Geophysics ◽  
1986 ◽  
Vol 51 (7) ◽  
pp. 1462-1471 ◽  
Author(s):  
Brian R. Spies ◽  
Dwight E. Eggers
Keyword(s):  
Apparent Resistivity ◽  
Early Time ◽  
Asymptotic Formulas ◽  
Voltage Response ◽  
Late Time ◽  
Induced Voltage ◽  
Resistivity Curve ◽  
Transient Electromagnetic ◽  
Electromagnetic Methods ◽  
Tem Method

Problems and misunderstandings arise with the concept of apparent resistivity when the analogy between an apparent resistivity computed from geophysical observations and the true resistivity structure of the subsurface is drawn too tightly. Several definitions of apparent resistivity are available for use in electromagnetic methods; however, those most commonly used do not always exhibit the best behavior. Many of the features of the apparent resistivity curve which have been interpreted as physically significant with one definition disappear when alternative definitions are used. It is misleading to compare the detection or resolution capabilities of different field systems or configurations solely on the basis of the apparent resistivity curve. For the in‐loop transient electromagnetic (TEM) method, apparent resistivity computed from the magnetic field response displays much better behavior than that computed from the induced voltage response. A comparison of “exact” and “asymptotic” formulas for the TEM method reveals that automated schemes for distinguishing early‐time and late‐time branches are at best tenuous, and those schemes are doomed to failure for a certain class of resistivity structures (e.g., the loop size is large compared to the layer thickness). For the magnetotelluric (MT) method, apparent resistivity curves defined from the real part of the impedance exhibit much better behavior than curves based on the conventional definition that uses the magnitude of the impedance. Results of using this new definition have characteristics similar to apparent resistivity obtained from time‐domain processing.

New insights into the Hercynian Orogeny, and their implications for the Paleozoic Hydrocarbon System in the Arabian Plate

GeoArabia ◽  
2009 ◽  
Vol 14 (3) ◽  
pp. 199-228 ◽  
Author(s):  
Mohammad Faqira ◽  
Martin Rademakers ◽  
AbdulKader M. Afifi
Keyword(s):  
Oil And Gas ◽  
Seismic Imaging ◽  
Structural Features ◽  
Source Rocks ◽  
Arabian Plate ◽  
Arabian Shield ◽  
Tectonic Event ◽  
Angular Unconformity ◽  
The North ◽  
Hercynian Orogeny

ABSTRACT During the past decade, considerable improvements in the seismic imaging of the deeper Paleozoic section, along with data from new well penetrations, have significantly improved our understanding of the mid-Carboniferous deformational event. Because it occurred at the same time as the Hercynian Orogeny in Europe, North Africa and North America it has been commonly referred to by the same name in the Middle East. This was the main tectonic event during the late Paleozoic, which initiated or reactivated many of the N-trending block uplifts that underlie the major hydrocarbon accumulations in eastern Arabia. The nature of the Hercynian deformation away from these structural features was poorly understood due to inadequate seismic imaging and insufficient well control, along with the tectonic overprint of subsequent deformation events. Three Hercynian NE-trending arches are recognized in the Arabian Plate (1) the Levant Arch, which extended from Egypt to Turkey along the coast of the Mediterranean Sea, (2) the Al-Batin Arch, which extended from the Arabian Shield through Kuwait to Iran, and (3) the Oman-Hadhramaut Arch, which extended along the southeast coast of Oman and Yemen. These arches were initiated during the mid-Carboniferous Hercynian Orogeny, and persisted until they were covered unconformably by the Khuff Formation during the Late Permian. Two Hercynian basins separate these arches: the Nafud-Ma’aniya Basin in the north and Faydah-Jafurah Basin in the south. The pre-Hercynian Paleozoic section was extensively eroded over the arches, resulting in a major angular unconformity, but generally preserved within the basins. Our interpretation suggests that most of the Arabian Shield, except the western highlands along the Red Sea, is the exhumed part of the Al-Batin Arch. The Hercynian structural fabric of regional arches and basins continue in northern Africa, and in general appear to be oriented orthogonal to the old margin of the Gondwana continent. The Hercynian structure of arches and basins was partly obliterated by subsequent Mesozoic and Cenozoic tectonic events. In eastern Saudi Arabia, Qatar, and Kuwait, regional extension during the Triassic formed N-trending horsts and graben that cut across the NE-trending Hercynian mega-structures, which locally inverted them. Subsequent reactivation during the Cretaceous and Neogene resulted in additional growth of the N-trending structures. The Hercynian Arches had major impact on the Paleozoic hydrocarbon accumulations. The Silurian source rocks are generally preserved in the basins and eroded over the arches, which generally confined Silurian-sourced hydrocarbons either within the basins or along their flanks. Furthermore, the relict Hercynian paleo-topography generally confined the post-Hercynian continental clastics of the Unayzah Formation and equivalents to the Hercynian basins. These clastics contain the main Paleozoic oil and gas reservoirs, particularly along the basin margins where they overlie the sub-crop of the Silurian section with angular unconformity, thus juxtaposing reservoir and source rock.

scholarly journals THE INTENSITY OF THE HEAVY METALS BY TOPINAMBUR IN THE CONDITIONS OF THE OIL-POLLUTED AREAS

2021 ◽  
Vol 52 (6) ◽  
pp. 1334-1345
Author(s):  
V. I. Lopushniak ◽  
H. M. Hrytsuliak
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Oil And Gas ◽  
Jerusalem Artichoke ◽  
Green Mass ◽  
Control Option ◽  
The Village ◽  
Mass Increase ◽  
Maximum Content ◽  
Sludge Application

This study was aimed to investigate  the ability of Jerusalem artichokes (Helianthus tuberous L.) to absorb heavy metals in an oil-contaminated ecosystem.  The research was carried out in a  territory of the oil and gas pipeline  at the village of  Bytkiv of Nadvirna district.  Jerusalem artichokes were used for this study and planted on an area of 25 m2.  The area of the experimental field in the village of  Maidan of Tysmenytsia district (control option № 1).  A total of eight treatments of the experiment with different rates of sewage sludge.  It is established that the concentration of heavy metals in oil-contaminated soil and Jerusalem artichoke plants increases with increasing the amount of fertilizers in the soil. The maximum content of metals in the tested soils, green mass and Jerusalem artichoke roots was observed  mainly in the variant of sewage sludge application at the rate of 40 t/ha and fertilizer N10P14K58.The green mass and roots of Jerusalem artichoke exhibited the highest content  of heavy metals absorption the transition coefficients of metals in the system "roots - green mass" increase in the following : Pb → Co → Ni → Cd.  The coefficients of biological absorption of metals by Jerusalem artichoke increase in a number of elements: Co  → Ni → Ld → Ca. Where as  The coefficients of biological accumulation of heavy metals with Jerusalem artichoke increase in a number of elements following series : L → Co → Ni → Ca. It is recommended to use Jerusalem artichoke as a phytoremediator of man-made areas.

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