Space imaging for oil&gas prospecting The Earth surface bearing outcrops of geological objects is the source of the airspace information. The particular features in the space images are directly or indirectly linked either to the geological object itself or its reflection in the upper surface morphology patterns. Earth surface can be considered as an uppermost geological boundary bearing traces of protruding tectonic activity. It is first and foremost reflected in such features as lineaments, ring, circular and arch structures. Lineaments are usually corresponding to the Earth’s crust faults, and they are displayed at the day surface like elongated relief forms, boundaries of such relief forms, and like elements of hydrographic network, which are geologically determined by zones of soil and vegetation contrast. The rings, circles, ovals, and arches revealed in space images are displaying, similarly to lineaments, in hydrography and other landscape elements. The circle and oval bodies may correspond to bar-like structures, basement highs, or buried reef massifs. Lineaments and ring structures revealed by space images reflect the resulting compliance with the active (subsurface) tectonic – i.e. the disjunctive and folded deformations of the sediment cover of different extents and depths – down to the Earth crust basement deformations. The airspace methods take special and inherent place among the sources of geological and geophysical information; They must be treated as complimentary to other methods. In such way they help to mitigate risks in oil & gas prospecting providing additional insight into the whole complex of available data.

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Compiled by: principal expert in the aerospace geological researches Dr. Alexander Yantsevitch Tetrale Group Inc.

Example of SAR images

California (Northern America)

Zambia (Africa)

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Example of an IR image •

The couple of images covers a part of the ArizonaWhite Mountains. Left: composition of 3 channels of the IR image; right – pseudo-colored composite prepared of the visible diapason data

•

The arrow shows the large fault displayed in the IR image

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Example of a multispectral space image Landsat TM (west coast of the Keweenawan penincula, Northern Michigan)

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Example of structural imterpretation of a Landsat TM image (California border,USA)

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Revealing of a fault using the image transformation by quantization method A • •

А – the initial image IRS LISS-III, Sustchano-Perzhans’ka zone (Ukraine) the same IRS LISS-III, processed

B

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Transformation of Landsat MSS image using program package «ERDAS IMAGINE» Types of transformation:Spatial Enhancement (Texture) and Hyper Spectral Tools (Signal to Noise) Scale: 1:1000000

Day surface expression of the tectonically related subsurface features Left: Diagram of a strike-slip fault and associated fracturing resulting from tectonic stresses (from Berge, 1994).

Right: Landsat TM image of strikeslip faulting and fracturing from tectonic activity near Los Angeles, California.

Comparison of the ancient fault network and the recent and modern active faults revealed by space images allows outlining among the last ones the two main classes: the inherited and the neogenetic ones The inherited faults (matched or allied by its spatial location and orientation) inherit the fragments of the previously existing network of platform or pre-platform disjunctive dislocations The newly formed active faults have low amplitudes or represent elongated systems of sub-parallel megafractures (no- or low-amplitude disjunctions)., and they are not linked spatially to the paleo-faults. Such discontinuities usually do not have any visible vertical or horizontal displacements, and they are manifested in dissipated form within a wide belt (zone). They may be determined by the complex of indirect indicants displayed in relief, drainage system, landscape, structure of platform cover and basement surface, increased level of rock fracturing, anomalies of geophysical fields, etc. The indicants of differentiated movement along the active faults are terminal moraine, esker, and other ridges, large glacier dislocations, and erosion cutting-ins (of glacier trenches and river valleys) match by location and strike. 8

The principal scheme of the possible fault location in the lithosphere, and their displaying at the day surface and in space images in form of lineaments (by Makarov V.I., 1983) • b

b

A a b

•

a b

B a

a

b

b

a

a

C

A,B – faults not reaching the day surface and overlapped by geological rock masses at big (1) or significant (2) depths of lithosphere, in a crosssection; C – faults not reaching the day surface and having flat-lying (1) and vertical (2) location of the displacement plane (zone) in the lithosphere cross-section. 1 - faults; 2 – Earth’s crust blocks divided by faults; 3 - Earth’s crust layers unaffected directly by faults 4 – variants of possible displacements along faults; 5 – cone of the mechanical deformations propagation; 6 – non-regular upflow of depth fluids, gases, and heat; 7 – cone of dissipation of fluids, gases, and warm streams; 8 – conventional curve of the heat flow above a fault zone; 9 - conventional intensity of anomalies at the day surface corresponding to intensity of morphology of the lineaments displaying in the space images.

Views: a cross-section; b – aero-space image 9

Manifestation of active faults in structure of modern sediments and in modern relief (by Karabanov A.K., 2009) seismotectonic moraines

sand bodies in moraines

hydrogeochemial anomalies

flexures and disruptions of layers

glasier disloctions

glacier beds

fault scarp split-offs

terminal moraines

eskers and fill-up terminal ridges

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Correspondence between eskers and esker-like ridges and active faults •

Among various relief forms of glacier origin, the elongated erosion cutting-ins (glacier beds, valley outwash plains) or eskers and esker-like ridges appearing in large fractures inside the glaceir bodies are the most linked to active faults. Such cutting-ins are mainly licated above large basement faults.

• • • • • •

1 — eskers and esker-like ridges 2 — lakes, 3 — active fault 4 — sands 5 — clays 6 — disjunctions

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Evidence of the Mosarsky lineament (Belarus), revealed by space images, in the modern relief The lakes are dashed , the solid lines represent eskers and esker-like ridges. The lineament is reflected by: • location of elongated lakes or swamp depressions on either side of it; • the ridges form narrow peninsulas dividing such lakes and bays; • the width of ridges is changeable and varies from 50-70 m to 0.3—0,6 km. In the intervals where the lineament is formed by several subparallel small ridges, the total width reaches 0,8—0,9 km.

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Scheme of bogs and tectonic dislocations for one of areas of the Sustchano-Perzhanska tectonic zone (by K.S. Dzhagiriants)

1-bogs, swamped depressions; 2- tectonic dislocations 13

Schematic diagram illustrating multiple roles that a fault plays in transmitting or sealing hydrocarbons • • • • •

vertical reservoir connectivity; reservoir compartmentalisation; leakage to surface; juxtaposition seal; migration to trap.

Colligation of prospecting and exploration drilling results, and also the field exploitation data obtained by various researchers has shown that areas with improved reservoir properties of productive horizons are located in plane along lineament zones. These zones were affected during the neotectonic stage by active differently directed movements creating fracturing zones within the reserviors. At the same time such movements determined persistent appearance of lineaments in the modern landscape. It is determined that such dislocations are corresponding to zones of anomalous densities of terrigene and carbonate rocks characterized by reservoirs with rather high storage capacities. This gives the possibility to use the results of airspace surveys for predicting of fractured reservoir zones with increased storage capacities, drilling mud loss zones, and abnormal reservoir pressures. The regional faults having rather big (up to 1.5-2 km) vertical displacements of productive horizons, were lowactive at the neotectonic stage. Most probably that caused absence of rocks with increased reservoir properties and the fact that they are poorly defined in landscape. The outlined regular dependencies between creation of zones with increased reservoir properties of productive horizons, their neotectonic activity and degree of landscape gives broad possibilities not only to use the airspace methods for regional geological and geophysical surveys but also for detailed prospecting of oil and 14 gas fields and their exploration.

The Deep River deposit and its alignment with a fault zone • The structural map of the Traverse group (Devonian) bottom and the presumable cross-section of the Deep River oil deposit: • 1- oil wells, • 2 – structure contours of the Traverse group bottom, • 3 –limestones, • 4 – clays; • 5 – porous cavernous dolomites, • 6 oil deposit

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Alignment of the oil deposits and the fault zones revealed by geophysical data at the eastern slope of the Eastern European platform

• а – oil fields with deposits in terrigene Devonian sediments • b – oil fields where deposits in terrigene Devonian sediments were not revealed • c – lines of the graben-like troughs determined by drilling, • d – basement faults by geophysical data, • e – prospective oil deposit areas

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Pattern of the main faults and oil&gas deposits in Predkarpatie region, Ukraine • 1- marginal fault of the Eastern European platform (MPF), • 2 – regional thrusts and overthrust sheets; • 3- sub-vertical fractures; • 4- sub-vertical fractures in the basement, • 5- transverse fractures

B

A

F

Deposits:

C

E

• 6 - oil, • 7- gas, • 8 – oil&gas.

D

Main fractures:

B A F

E

A-, B-, C- , ...

C

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Allocation of the oil producing well pattern and fractures of the oil area Wady Bat, Morocco • 1- structure contours of the Miocene bottom, section 25 m, • 2 - thrust, • 3 - normal fault, • 4 – wells producing oil from the Palaeozoic basement, • 5- – wells producing oil from the Mesozoic sediments, • 6 – wells producing oil from the Mesozoic and Palaeozoic reservoirs, • 7- dry wells

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Fracture analysis of Eastern Asian study area based on satellite data with 2 m resolution.

Detailed airspace surveys are helping to obtain details of the known deposits and revealing of new local objects. Detailed geological, geomorphological, and structural interpretation of mid and large scale images is carried out as part of a complex works for processing and partial re-interpretation of the existing geological and geophysical factual data. Detailed works are carried out within the oil-producing areas during prospecting and exploration stage. The object of their studies are local structures or their parts. The goal of the detailed surveys is refinement of the known exploratory prospects, revealing of new prospecting plots (objects) and preparation of them for detailed seismic surveys. The possibility to reveal in the space images of local structures prospective for oil&gas deposits is mainly determined by their inherited development, determined manifestation of structures in the modern relief, character of Quarternary cover, distribution of soils, vegetation, and moisture degree. For revealing of these peculiarities, also landscape spectral characteristics are needed. The correlation between spatial distribution of hydrocarbon deposits and activity of structural forms during the Neogene-Anthropogene stage is outlined. 19

Examples of structural oil&gas traps

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Ring structures and Oil & Gas deposits of a southeast part of the Volga-Ural petroleum province (Gabrielyants and others, 1984.)

Collation of the ring structure and the tectonic map of the DneprovoDonetsky basin Gas and gas condensate deposits

salt doms

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Scheme of the geological deciphering in the ring structure area

 In conditions when the bedrocks are overlapped by a thick cover of Quarternary sediments, and the landscapes are heavily changed, the anticline structures can be poorly seen in the space images.  The example is the local ring structure located at the northern edge of the Dneprovko-Donetsky basin (Ukraine) close to Skvortsovskoye and Yul’evskoye oil-gas condensate deposits. It may be seen in the space images (especially Landsat TM and Landsat ETM) well enough.  The structure has ellipsoidal concentric form, its long axe has north-east extention; the structure sizes are 12x7 km. In the modern relief it is displyed as an uplift slotted along the long axe by a river valley. In the detailed structural maps of the Skvortsovskoye and Yul’evskoye plots for the reflecting horizons Vb2-п (C1V2) и Vb3-п(С1v1), the structure is not displayed, but the external arch elements of the structure match very well to the disjunctive dislocations displayed in the same maps. The contours of the Skvortsovskoye and Yul’evskoye deposits adjoin orthomorphically to the peripheral part of the structure.

The ring structure displayed in the space image “Landsat TM” is interpreted as an anticline (Dneprovsko-Donetskaya province, Ukraine)

elements of the ring structure and lineaments aligning with faults revealed by geological and geophysical data

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3-D image of a ring structure in the modern relief (digital relief model with overlapped space image)

Correspondence of the space images interpretation scheme and the structural maps of the reflecting horizons of the oil – gas condensate deposits gas condensate deposits oil deposits fractures revealed by seismic data

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GEOLOGICAL PROSPECTING FOR OIL&GAS STRUCTURES WITH USE OF AIRSPACE METHODS, FOR SHELF AREAS  Use of airspace methods for oil&gas prospecting reveals capability of direct interpretation by space images of the sea bottom up to sea depths 70-90 m. Sea bottom interpretation by space images is possible for shoal water (internal shelf), which is considered as a «dead zone» due to the fact that the area is inaccessible for survey ships.

The SAR image (5.6 cm range) , ERS space vehicle, Western Black Sea region, scale 1:1000000

 Using the indirect indicants like types of rough water, change of the water sea color and transparency, it is possible to interpret the sea bed elements within the internal shelf and continental slope. The anticline structures may be interpreted by space images in the shelf areas rather confidently. As a rule they are displayed in the sea bed relief in form of rises and accumulative forms (underwater and overwater bars), and bends of the buried river valleys.  Comparison of the supposed contours of anticline structures revealed by space images, with geologicalgeophysical and seismic data shows a good convergence with contours of anticline structures revealed by such data, and provides a surplus of information for the structures, which were not yet determined by geological and geophysical methods.

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Mosaics of SAR images for the north-eastern shelf of the Black Sea

 For interpretation of the marine areas, various types of space images mainly of medium spatial resolution (10-45 m) and different regional and local generalization levels are used. Some extended lineaments matching to the large fault or are located at their offshore continuation may be revealed.  Some of the regional ring structures match well to the positive and negative anomalies of the gravity and magnetic fields, to the rises having Permo-Triassic age, and also to many structural elements revealed in the structural maps of the reflecting horizons.  Majority of the ring structures are well matching to the structures revealed by seismic data. This fact confirms the space image interpretation effectiveness for water areas within shelf zones.

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The linear elements of the transformed SAR image corresponding to the Odessko-Temruksky fault; scale 1:1000000

The linear elements of the transformed SAR image corresponding to the Dunajsko-Donetsky fault; scale 1:1000000

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References • The temporal methodic reccomendation for use of the space mapping for geological investigation of the platfrom part of the USSR/ Nikolaenko B.A., Veremeyev P.S., Kubyshkina L.K., Pazinich N.V. – Kiev, Mingeo USSR, TsTE, 1983, 77p. • Principles and methods of remote sensing for solid minerals prospecting/S.-Peterbourg, 1992, 144 p. • Remote sensing of the Earth: the disctionary (ed. V.S. Gotinyan). Nat.Acad. Sci. Ukraine, DNVTs «Priroda», Kiev, 1996, 518 p. • The new methods of the airspace surveys: procedure manual for thematic interpretation of airspce data/Lyal’ko V/I., Fedorovsky O.D., Pererva V.M., e.a. – Kiev, 1999, 264 p. • Neotectonics and neogeodynamics of the western part of the East-European platform/ A.K. Karabanov, R.G. Garetsky, R.E. Aisberg – Minsk, Belarus, Nauka, 2009. – 183 p. • Pertsov A.V., Antipov V.S., Pital S.V. – the remote-sensing base for the maps of geological content (creation, use, possibilities of improvements). – Moscow, NIIKAM, 2004 • Micchack A.G., Filipovich V.E., e.a. Development of the procedure manual for airspace surveys and use of their results for geological prospecting» – Kiev, TsAKDZ IGN NAN, 2005, 182 p. • Multispectral methods for remote sensing of the Earth for use of natural resources (ed. V.I. Lyal’ko, M.O. Popov), Kiev, Naukova dumka, 2006, 357 p.. • Sharkov V.V. THe modern and recent geological processes in the shelf areas. In; Space information for geology. – Moscow, Naka, 1985, 536 p. • The Remote Sensing Tutorial (RST), NASA, 2003 • Geo energy and Geo information. TNO Built Environment and Geosciences • Geological Survey of the Netherlands, 2009, 212 p. • Fundamentals of Remote Sensing. A Canada Centre for Remote Sensing Remote Sensing Tutorial. Natural Resources Canada, 2008. 258 p. 27