|
|
Showing 1 - 4 of
4 matches in All Departments
This book provides an overview of the major changes induced by
hydrocarbons (HCs) affecting rocks and surface sediments and their
implications for non-seismic exploration methods, particularly for
marine territories near Cuba. It examines the use of a digital
elevation model (DEM) at 90x90m resolution for the detection of
subtle, positive geomorphic anomalies related to hydrocarbon
microseepage (vertical migration) on possible oil and gas targets.
The results support the conclusion that the DEM data provides a low
cost and fast offshore oil and gas preliminary exploration
strategy. This data is useful serving to focus prospective areas
with supplementary unconventional methods such as magnetic-induced
polarization (MIP), useful to propose more expensive volumes for
detailed 2D-3D seismic surveys.
The evolution of geological cartography in Cuba in its more than
135 years of history has been possible through the consultation of
numerous archival reports, publications, maps and personal
interviews with different authors and geologists of vast
experience. A brief critical analysis is made of the increase in
the degree of geological knowledge of the country since the
elaboration of the Geological Sketch of the Cuban Island at a scale
of 1: 2 000 000 (Fernandez de Castro, 1883), first of Cuba and of
Ibero-America, until the most recent Digital Geological Map of Cuba
at scale 1: 100 000 (Perez Aragon, 2016). Cuba and its surroundings
are a geological mosaic in the southeast corner of the North
American plate with rocks from many different origins, from
Proterozoic to Quaternary, extended along the southern border of
the plate. From the Eocene, this belt has been dissected by several
great faults, related to the development of some great oceanic
depressions (Cayman trough and Yucatan basin). The fossil record of
Cuba, which covers approximately the last 200 million years of life
on Earth, is rich in very varied fossils, witnessing a wide
diversity of organisms, both animals and plants, that inhabited the
Antillean and Caribbean region; and that constitute the inheritance
of the biological diversity that the current Cuban archipelago
exhibits. As a result of the preparation of the Cuban Metallogenic
Map at scale 1: 250 000, forty-one models and eight sub-models of
metallic mineral deposits were identified. These models, of
descriptive-genetic type, together with the analysis of their
spatial distribution and their relationship with geology, allowed
the identification and mapping of ten mineral systems, linked to
the geodynamic environments present in the Cuban territory. Cuba
has large deposits of limestone, loam, dolomite, kaolin, gypsum and
anhydrite, rock salt, marbles, sands and clays of different types,
zeolites, peat, therapeutic peloids and many more. There are
manifestations of decorative and precious rocks such as jasper,
jadeite, different varieties of quartz and even xylopals. A
compilation of geochemical data of oceanic basalt samples from
previous works, together with data of analyzed samples during this
study in order to discuss geochemical criteria based on immobile
element (proxies for fractionation indices, alkalinity, mantle flow
and subduction addition), provide a comprehensive ophiolite
classification according to their tectonic setting. This book
addresses different facets of the geological knowledge of Cuba:
history of its cartography, marine geology, fossil record,
stratigraphy, tectonics, classification of its ophiolites,
quaternary deposits, metallogeny and minerageny.
The so-called "Non-conventional geophysical-geochemical exploration
methods" are used, in the particular case of oil and gas
exploration, for the detection and mapping of active microseepage
of light hydrocarbons with a vertical nature on the gas-oil
accumulations. The non-seismic exploration methods used in Cuba
are: Remote Sensing, Gravimetry, Aeromagnetometry, Airborne Gamma
Spectrometry (AGS) and Morphometry (non-conventional, from the
Digital Elevation Model 90x90m). The AGS also classifies, as a
non-conventional geophysical-geochemical method, together with the
Redox Complex. Besides, it is of interest to know the
geological-structural framework where these microseepage occur.
That is why the benefits of using these methods (excluding Redox
Complex), prior to their integration with geological and seismic
data, translate into a first approximation, valid for an initial
understanding of geology and mapping of favourable areas of
possible gas-oil interest. Finally, from the implementation of
these methods (including Redox Complex), perspective sectors for
oil and gas are obtained, once the integration with geology and
seismic has been carried out. The book presents a brief theoretical
account of the methods used and, as practical results, a set of
perspective sectors of possible interest for exploration in Cuba.
As a complementary result, the book also offer an evaluation of the
areas that meet the petroleum-geologist premises for the presence
of large accumulations of high quality oil in Cuba.
This book assesses the use of various non-seismic and
non-conventional oil and gas exploration methods in Cuba. In
addition to discussing the benefits of these methods, the book
demonstrates how they can be combined with geological data and
conventional methods, leading to a better evaluation of prospects
and exploration risks. The authors describe how potential new
gaso-petroleum sites in the Pina-Ceballos and Sancti Spiritus
regions can be effectively mapped. The geophysical-geochemical
exploration techniques combined in the Redox Complex method are
used to identify and evaluate these sites. Areas of interest are
mapped based on the presence of a combination of indicator
anomalies, mainly derived using gravimetric, aeromagnetic and
airborne gamma spectrometry. The geochemical study concentrates on
two petroleum-rich regions, one in northern and one in southern
Cuba. The scope also includes the seas to the south of Cuba, which
are studied with non-seismic exploration tools such as the Digital
Elevation Model, which employs morphotectonic regionalization.
|
|