Geology Of Basin Research Articles

Exploration of an unconventional petroleum resource through extensive core analysis and basin geology interpretation utilising play element methodology: the Lower Goldwyer Formation, onshore Canning Basin, Western Australia

Theia Energy Pty Ltd1 (Theia Energy) discovered a potential unconventional hydrocarbon resource in the Ordovician Lower Goldwyer (GIII) Formation shale located on the Broome Platform of the onshore Canning Basin. The collation, processing, analysis and interpretation of all available regional data culminated in a successful exploration well, Theia-1 (drilled in 2015), which, based upon petrophysical and core analyses, intersected a 70 m gross oil column at 1500–1570 m depth. Theia-1 recovered essential core and wireline log data required to analyse and assess the play elements and reservoir properties necessary for a viable shale oil and gas development. Utilisation of an ‘Unconventional Play Element’ methodology has proven the unconventional hydrocarbon potential of the GIII Formation, and preliminary modelling indicates that economic stimulated flow rates may be achieved. Further operations (a test well with multi-stage hydraulic fracture stimulation) are scheduled in the coming permit year to further quantify the presence of extractable organic matter in the GIII Formation, assess hydrocarbon flow rates, determine fluid composition and appraise commercial viability. This paper will discuss Theia Energy’s exploration campaign in the onshore Canning Basin starting with the regional evaluation, which encompassed all available geoscience data (offset wells, pre-existing seismic and potential analogue fields) and modern specialised shale analysis (sequence stratigraphy, paleogeography, geochemistry, unconventional petrophysics and petroleum systems modelling), to develop a robust regional geological model for the GIII Formation. Pre-drill analysis reduced exploration risk and successfully identified the key geological play elements essential for the successful Theia-1 exploration evaluation program.

Using AEM and GMR Methods for Non-Invasive, Rapid Reconnaissance Mapping and Characterisation of Groundwater Systems in the Kimberley Region, Northern Australia

The East Kimberley Region of north-western Australia has been identified as a priority for potential agricultural development. Within this region, the Ord Bonaparte Plain is remote, with limited access in an area of great cultural and environmental sensitivity. Initially, spatio-temporal mapping using remote sensing (and potential field) data, combined with data on the deeper basin geology was used to plan an airborne electromagnetics (AEM) survey. The relatively resistive nature of the basin sediments has enabled the AEM to map the hydrostratigraphy to depths of 300-500m, except in the coastal zone affected by seawater intrusion. Two overlying aquifers, separated by a faulted, ‘leaky’ aquitard, have been identified.The AEM and remote sensing data were subsequently used to plan a ground magnetic resonance (GMR) survey. The latter has enabled a water table map to be constructed in an area with almost no drilling, while also enabling key aquifer properties to be determined. The target aquifer has a high free water content and high transmissivity. The GMR results have been validated by drilling, borehole Nuclear Magnetic Resonance (NMR), and induction logging.Integration of AEM, GMR and temporal (Landsat) remote sensing data has enabled rapid mapping and characterisation of the groundwater system in a data-poor, culturally and environmentally sensitive area. These data have also revealed complex faulting within and bounding the aquifer system, delineated the sea-water intrusion interface, and mapped groundwater dependent ecosystems. These data have been used to target drilling and pump testing that will inform groundwater modelling, water allocations and development decisions.

Geology of the Central Sivas Basin (Turkey)

ABSTRACT This paper presents a revised geological map at the 1/50,000 scale of the Central Sivas Basin together with a synthetic stratigraphic chart and cross-sections. The map covers an area of approximately 9840 km² within the Eastern Anatolian orogen. The structure of the studied area is dominated by three major tectonic domains: (i) to the south, a north-verging thrust wedge involving Maastrichtian – Eocene sediments deposited onto an ophiolitic basement, (ii) in the center an Oligo-Miocene domain shaped by salt tectonics detached above the thrust wedge, along a late Eocene salt layer, and, (iii) to the north the Pliocene depocenter onlapping onto the Kırşehir basement. The central halokinetic domain exhibits two generations of minibasins (respectively, early Oligocene and late Oligocene to late Miocene), separated by an evaporite canopy. The map includes new stratigraphic correlations for the pre-salt stratigraphy and improve the comprehension of the southern fold-and-thrust-belt.

A New Method for Environmental Flow Assessment Based on Basin Geology: Application to the Ebro Basin.

The determination of environmental flows is one of the commonest practical actions implemented on European rivers to promote their good ecological status. In Mediterranean rivers, groundwater inflows are a decisive factor in streamflow maintenance. This work examines the relationship between the lithological composition of the Ebro basin (Spain) and dry-season flows, in order to establish a model that can assist in the calculation of environmental flow rates. The explanatory variable used in the proposed model is easy to calculate and is sufficiently powerful to take into account all the required characteristics. The model has a high coefficient of determination, indicating that it is accurate for the intended purpose. The advantage of this method is that it requires very little data and provides a simple estimate of environmental flow. The results of this research also contribute to knowledge of the variables that influence low-flow periods on rivers in the Ebro basin.

Investigations into the Holocene geology of the Dead Sea basin

This paper discusses the geological history and paleoclimate of the Dead Sea region based on drill hole data. A composite stratigraphic column for the Holocene period, of multiple lime carbonate and halite sedimentation, has been constructed for the southern Dead Sea basin. Integration of stratigraphic data with geochronology has shed new light on our understanding of Holocene sedimentation rates, tectonics, diapirism, the formation of sinkholes, lake levels, and paleoclimate. During this period, the southern basin has subsided at a rate of 8.5–11 m/ka, while the subsidence of the northern basin may have reached 25–30 m/ka. The Holocene has been divided into 13 major climatic intervals, starting with a very arid climate from ~ 11,700 to ~ 8800 BP, where halite precipitated in both basins, with the Dead Sea possibly reaching a level of ~ − 419 m msl. After ~ 8800 BP, there was a very intense pluviatile period, with the formation of alluvial fans opposite wadi channels reaching up to 45 m in thickness. An attempt has been made to construct a new Dead Sea-level curve, based on the mineralogical data and corrected for diapirism under the Lynch Straits and tectonic subsidence. The previous lake-level curves were based on elevations of shore-line facies in a tectonically active basin with differential subsidence. A new hypothesis is presented for sinkhole formation in both the northern and southern basins, which is considered to be initiated and controlled by active faulting, with the dissolution of the halite by artesian, undersaturated waters, more than the receding Dead Sea level. The brine level is rising in the southern basin. The findings from this research can act as a model for understanding the development of ancient and modern evaporites worldwide.

Hydrodynamics and hydrocarbon trapping: Concepts, pitfalls and insights from case studies

Abstract Tilted contacts are observed in many oil and gas fields. They are generally attributed to the effect of hydrodynamics. Hydrodynamic flow exists in almost all geological basin types of the Wilson cycle, from passive margins to foreland basins to mountain chains. There are various geological processes driving regional hydrodynamics. Flow is regulated by permeability variations which are given by the geological framework. The role of faults as partial permeability barriers may be a significant regulator for flow. Hydrodynamics is best recognized by using the principles of hydraulic head. However, hydraulic data must be carefully interpreted to avoid pitfalls such as transition zones where variable oil saturation may be falsely interpreted as tilted contacts. In sedimentary basins, we distinguish two different hydrodynamic settings where flow is either mainly gravity-driven (or centripetal), or mainly compaction-driven (or centrifugal). In both cases, hydrodynamics can enhance hydrocarbon trapping. Gravity driven processes are particularly important in the Arabian Shield and North Africa. Centrifugal and centripetal phenomena can co-exist in the same basin, e.g. Mahakam delta or Douala Basin. Turbidites occur typically in centrifugal settings. Hydrodynamic concepts applied to petroleum exploration are not frequently used in industry despite being known for a long time. They may however become increasingly important in conventional exploration as static plays are rapidly being drilled up and the remaining exploration potential of sedimentary basins is increasingly affected by stratigraphic and hydrodynamic trapping components.

Review of the geology of mamfe sedimentary basin, SW Cameroon, Central Africa

Review of the geology of mamfe sedimentary basin, SW Cameroon, Central Africa

Excursion of the geology and topography of Ueda basin prospered the Sanada family

Excursion of the geology and topography of Ueda basin prospered the Sanada family

Groundwater monitoring of the deep aquifer for the construction phase of the Crossrail project

The Crossrail project is a new underground railway through the heart of London. It will connect with 110 km of new or upgraded sections of surface rail to Reading, Shenfield and Abbey Wood. The route runs through typical London Basin geology. Ground investigations began during the 1990s and continued to 2012. A total of 1314 groundwater monitoring devices were installed and monitored at regular intervals. The groundwater monitoring strategy adopted by the project in preparation for and during construction included (1) establishment of a robust baseline and system for measuring changes to the baseline, (2) establishment of a series of sentinel wells to monitor any possible migration of third-party contamination sources and provide advance warning for construction dewatering sites and (3) performance of pumping tests. The sentinel wells were located to provide sufficient time to allow mitigation measures to be put into place without cessation of construction dewatering, thereby minimizing risk to the project. The pumping tests were carried out to demonstrate constructability, aid in the design of construction dewatering systems and provide support for the consent submissions on the impact of dewatering. Instrumentation was transferred to, and monitored by, the construction contractors but data were collated centrally by Crossrail. Contractors added their own instruments located either within or immediately adjacent to the structure to confirm dewatering levels or risk of base heave. The data were used for regular reporting to the Environment Agency in support of the dewatering permits and ensuring no interruption of supply to licensed abstractors.

An appraisal of the Permian palaeobiodiversity and geology of the Ib-River Basin, eastern coastal area, India

The Ib-River Basin situated in the east coastal area of India, in Odisha State is a south-eastern part of the Mahanadi Master Basin. A large number of plant macrofossils belonging to the Glossopteris flora were described and documented between 2006 and 2010 from various localities of the Barakar and Lower Kamthi formations of this basin. The floral components representing leaves, roots and fructifications in these assemblages belong to the Lycopodiales, Equisetales, Sphenophyllales, Filicales, Cordaitales, Cycadales, Ginkgoales, Coniferales and Glossopteridales. In the present study, all the available data pertaining to the biological remains, petrological analyses as well as the geology of this basin are reviewed and analyzed to deduce and reconstruct the biostratigraphy, palaeoclimate, palaeoenvironment and the landscape of this basin during Permian time in general and during the deposition of Barakar (Artinskian - Kungurian) and Lower Kamthi (Lopingian) formations in particular. The floral composition suggests the prevalence of a temperate climate with a slight change from warm moist to warm dry conditions during the deposition of the Barakar Formation and warm and humid during the deposition of Lower Kamthi sediments. Distribution of various plant groups in the Barakar and Lower Kamthi formations have been shown to depict the biodiversity trends. Vegetational reconstructions during the deposition of the Barakar and Lower Kamthi formations around the Ib-River Basin have also been attempted based on all the fossil records from this area. The status of unclassified Barakar and Kamthi formations has been redefined. Apart from megafloristics, the palynology of the basin is also discussed. Possible marine incursions and marine marginal environment in the Ib-Basin during Permian are overtly summarized on the basis of records of acritarchs, typical marine ichnofossils and evidences of wave activity in Lower Gondwana sediments of this Basin.

A new species of Deltamys Thomas, 1917 (Rodentia: Cricetidae) endemic to the southern Brazilian Araucaria Forest and notes on the expanded phylogeographic scenario of D. kempi

Deltamys is a monotypic sigmodontine rodent from the Pampas of South America. In addition to the formally recognized D. kempi that inhabits lowlands, an undescribed form Deltamys sp. 2n=40 was recently found in the highlands of southeastern Brazil. In the present study, we perform a phylogeographic reassessment of Deltamys and describe a third form of the genus, endemic to the Brazilian Araucaria Forest. We describe this new species based on an integrative analysis, using complete cytochrome b DNA sequences, karyology and morphology. Bayesian tree recovered two allopatric clades (lowlands vs. highlands) and three lineages: (i) the lowland D. kempi, (ii) the highland Deltamys sp. 2n=40, and (iii) Deltamys araucaria sp. n. Deltamys araucaria sp. n. is karyotypically (2n=34) and morphologically distinguishable from D. kempi (2n=37-38), showing a tawnier dorsum/flank pelage, presence of a protostyle, M1 alveolus positioned anteriorly to the posterior margin of the zygomatic plate, and several other distinguishing characteristics. A phylogeographic assessment of D. kempi recovered two haplogroups with significant differences in skull measurements. This phylogeographic break seems to have been shaped by the Patos Lagoon estuarine channel. The diversification in Deltamys might have been triggered by dispersal of older lineages over different altitudinal ranges in the Paraná geological basin.

Assessment of CO2 - EOR and Storage Capacity in South Sumatera and West Java Basins

A study of carbon dioxide-enhanced oil recovery (CO2-EOR) and storage capacity in South Sumatera and West Java Basins, Indonesia has been conducted in conjunctions with the project plans of Indonesia National Electric Company to build carbon capture and storage ready coal power plants in Bojonegara of West Java and Muara Enim of South Sumatera. The Bojonegara power plant comprises 2×1000 MWe Ultra Super Critical Units, while Muara Enim consists of 2×300 MWe subcritical units. Those two power plants will produce approximately 11 and 4 million tons of CO2 per year. The geology of South Sumatera and West Java Basins are proven to have kept oil and gas in place safely for long time periods and there are many oil and gas companies production still active in those basins. Those basins are confirmed to be used as storage of CO2, where capacity, injectivity, and confinement will be suitable to keep CO2 in place for a period of time. CO2 production from those power plants in South Sumatera and West Java may be offered to the nearby oil companies and transported to oil fields for CO2-EOR flooding to get additional revenue. A preliminary CO2-EOR screening has been done for the oil fields surrounding the power plants. There are two types of mechanisms for CO2-EOR, which depend on the nature of the oilfield: immiscible EOR and miscible EOR. Immiscible EOR occurs where the injected CO2 does not mix with the oil but instead displaces the oil from the area where the CO2 is injected and increases the pressure of the oil at the production wells so that it can be pumped out. Miscible EOR occurs where the supercritical CO2 mixes miscibility with the residual oil to make it less viscous and facilitating its flow to the production wells. A total of 127 oil fields in South Sumatera has been analyzed to select which of those fields fulfill CO2-EOR injection criteria. EOR reservoir screenings were performed on those oil fields on which detailed information was available using the screening criteria proposed by Taber et al. The criteria include a set of parameters such as API gravity, oil viscosity, current pressure, temperature, oil saturation, remaining oil, formation depth, thickness, porosity, permeability, and rock type which help to determine whether or not a reservoir is suitable for CO2-EOR injection. 96 fields are classified as miscible displacement while the remaining 31 fields are categorized as immiscible. The result shows that the potency of additional recovery from those fields is around 661 million stock tank barrels with CO2 requirement of approximately 243 million tonnes. In addition to EOR, pure CCS to inject the CO2 emission into depleted gas fields in West Java and South Sumatera regions is also considered. The maximum storage capacity of West Java gas fields is approximately 395 million tonnes, while the storage capacity of South Sumatera is around 537 million tonnes. The potential for storing CO2 in the saline aquifer was also calculated theoretically. The depleted gas fields and aquifers are considered enough to store the CO2 emission from the power plants as long as 25 years.

Novel basin modelling concept for simulating deformation from mechanical compaction using level sets

As sedimentation progresses in the formation and evolution of a depositional geologic basin, the rock strata are subject to various stresses. With increasing lithostatic pressure, compressional forces act to compact the porous rock matrix, leading to overpressure buildup, changes in the fluid pore pressure and fluid flow. In the context of petroleum systems modelling, the present study concerns the geometry changes that a compacting basin experiences subject to deposition. The purpose is to track the positions of the rock layer interfaces as compaction occurs. To handle the challenge of potentially large geometry deformations, a new modelling concept is proposed that couples the pore pressure equation with a level set method to determine the movement of lithostratigraphic interfaces. The level set method propagates an interface according to a prescribed speed. The coupling term for the pore pressure and level-set equations consists of this speed function, which is dependent on the compaction law. The two primary features of this approach are the simplicity of the grid and the flexibility of the speed function. A first evaluation of the model concept is presented based on an implementation for one spatial dimension accounting for vertical effective stress. Isothermal conditions with a constant fluid density and viscosity were assumed. The accuracy of the implemented numerical solution for the case of a single stratigraphic unit with a linear compaction law was compared to the available analytical solution [38]. The multi-layer setup and the nonlinear case were tested for plausibility.

Dry season limnological conditions and basin geology exhibit complex relationships with δ13C and δ15N of carbon sources in four Neotropical floodplains

Studies in freshwater ecosystems are seeking to improve understanding of carbon flow in food webs and stable isotopes have been influential in this work. However, variation in isotopic values of basal production sources could either be an asset or a hindrance depending on study objectives. We assessed the potential for basin geology and local limnological conditions to predict stable carbon and nitrogen isotope values of six carbon sources at multiple locations in four Neotropical floodplain ecosystems (Paraná, Pantanal, Araguaia, and Amazon). Limnological conditions exhibited greater variation within than among systems. δ15N differed among basins for most carbon sources, but δ13C did not (though high within-basin variability for periphyton, phytoplankton and particulate organic carbon was observed). Although δ13C and δ15N values exhibited significant correlations with some limnological factors within and among basins, those relationships differed among carbon sources. Regression trees for both carbon and nitrogen isotopes for all sources depicted complex and in some cases nested relationships, and only very limited similarity was observed among trees for different carbon sources. Although limnological conditions predicted variation in isotope values of carbon sources, we suggest the resulting models were too complex to enable mathematical corrections of source isotope values among sites based on these parameters. The importance of local conditions in determining variation in source isotope values suggest that isotopes may be useful for examining habitat use, dispersal and patch dynamics within heterogeneous floodplain ecosystems, but spatial variability in isotope values needs to be explicitly considered when testing ecosystem models of carbon flow in these systems.

Is pull-apart basin tectonic model feasible for the formation of Kashmir basin, NW Himalaya

Kashmir Basin in NW Himalaya is considered a Neogene-Quatermary piggyback basin that was formed as result of the continent-continent collision of Indian and Eurasian plates. This model however is recently challenged by a pull-apart basin model, which argues that a major dextral strike-slip fault that runs through the Kashmir basin is responsible for its formation. And here it is demonstrated that this tectonic model is structurally unrealistic, and poses problems with geomorphology, geology, and tectonic setting of Kashmir basin. The major flaw of the model remains its orientation, and geometry, because a major dextral fault, which form a pull-apart basin, cannot cut through the center of a basin. It is therefore shown that the recently suggested pull-apart model is structurally impossible, and thus the Central Kashmir Fault (CKF), a proposed major dextral fault of Alam et al. (2015), could not exist.

Physics-based seismic input for engineering applications: a case study in the Aterno river valley, Central Italy

In this paper, we present 3D physics-based numerical simulations, in the near-source region at the regional scale, of the 2009, April 6, L’Aquila earthquake (central Italy), based on improved models of the Aterno river basin geology and source kinematics. The simulations were carried out by an open-source code, SPEED, based on a discontinuous Galerkin spectral element method. The numerical mesh of the Aterno basin was built on a detailed subsurface geological model and on the evaluation of the dynamic properties of the soils. The source model was selected among the kinematic solutions available in the literature as the one that fits best the near-source observations. Broadband ground motions were then generated through a hybrid method, combining 3D low frequency waveforms with high-frequency stochastic synthetics. To provide an example of application as seismic input to earthquake engineering analyses in the time domain, results of this approach were used for 2D site response analyses at Castelnuovo, a village severely damaged by the earthquake, and in the neighborhood of which no seismic record was available. SPEED simulation satisfactorily reproduces the recorded accelerograms in the frequency range 0.1–0.7 Hz. The site response analysis at the local scale shows that the amplification of the hill is more significant at its natural frequency, due to topographic and stratigraphic factors, than at the peak of the seismic input simulated by SPEED, that is at about 3 s along the fault-normal component. The presented application supports the conclusion that 3D physics-based numerical simulations do have the potential to become an alternative for determination of input ground motion for earthquake engineering analyses, especially for those scenarios for which real records are not available.

Automating biostratigraphy in oil and gas exploration: Introducing GeoDAISY

Biostratigraphy is a key upstream activity. Drilling operations use biostratigraphic data derived from core samples extracted via boreholes (mud logging) in order to guide drilling processes and verify models of basin geology. Current manual data analysis relies on the existence of sufficient numbers of biostratigraphers to be available to fulfil industry needs. However, due to factors such as retirement, and that the number of people being trained in the requisite taxonomic skills has declined sharply over the last couple of decades; the available pool of expertise is dwindling. It is clear that if the high cost of drilling operations is taken into account, the current situation is untenable and in many ways represents a perfect storm.This pessimistic situation can be radically changed by augmenting human expertise using automated species identification tools based on artificial neural network technology. DAISY [Digital Automated Identification System], a proven system of this sort, could revolutionise commercial biostratigraphy operations by enabling microfossil identification to be undertaken by technicians. This would yield immediate benefits for the industry as it would permit routine work to be performed quickly and accurately by less skilful, cheaper and therefore more available staff; freeing biostratigraphers to concentrate on non-routine, more complex tasks. The feasibility study presented here indicates that DAISY can consistently identify microfossils to species, with repeatable, high levels of accuracy. Crucially, it can also act as a permanent repository for taxonomic knowledge, which is currently lost when experienced personnel retire. There might also be additional environmental and social benefits if this technology is widely adopted within the oil and gas sector: as DAISY technology is generic, it can easily be re-targeted to interpret seismic data or even to estimate the impact of upstream exploration activities on abutting ecosystems.

Hydrostructural setting of Riardo Plain: effects on Ferrarelle mineral water type

The exploitation of groundwater resources must always keep in account the geology and hydrogeological settings of the catchment basin for the sustainability of withdrawals, in order not to overexploit the aquifer. Especially, in the case of mineral water extraction, even more attention should be paid to understand what are the water-rock-gases interaction mechanisms, which allow obtaining a specific water chemistry. The case of Ferrarelle mineral water (western sector of Riardo Plain, Caserta) is particularly complex. Through the acquisition of a great amount of former geological and hydrogeological data and by new hydrogeological surveys, it has been possible to distinguish the aquifer levels, distinguishing four circulations over the Roccamonfina Volcano and in the Riardo Plain. The presence of volcanic and volcaniclastic deposits deriving from the Roccamonfina Volcano which cover a highlytectonized carbonate bedrock, allows the formation of two aquifers in hydraulic continuity. This mixing between the two aquifers allows, with the ascent of deep CO2 through faults in the carbonate bedrock, the formation of the typical chemical composition of the mineral water Ferrarelle. In the eastern sector of the plain, it is possible to distinguish the volcanic aquifer from the carbonate one, probably due to the presence of low permeability deposits.

Development of sedimentary geology of petroliferous basins in China

Abstract This paper gives a contrastive analysis of the main progress made in petroliferous basins sedimentary geology domestically and internationally, and discusses the main problems and their solutions in the development of petroliferous basins sedimentology in China, New developments include coarse-grained depositional sysytem, shallow-water deltic depositional system, beach bar depositional system, deep-water gravity flows, fine-grained depositional system, carbonate reefs, mixosedimentite, microbialite, seismic sedimentology and sedimentary physical simulation. It also reveals the developing gap of Chinese sedimentology in the areas of microbialite and sedimentary simulation, etc. and analyzes the sedimentary features and paleogeography pattern of prototype basins, multi-scale paleogeographic recovery during major tectonic movements, the different explanation of new sedimentology theories in the deep-buried sandbodies development. The paper details the difficulties when it comes to the typical depositional systems combination and the setup of sedimentary models in China. Therefore, the developing tendency is described of sedimentology theories like source to sink, sedimentary dynamics as well as regional sedimentology in China, seismic sedimentology, and studying methods and technologies in sedimentary simulation.

Representation of Geochemical Data in Geospatial Domain

Geochemical surveys are integral part of systematic geological survey to cover mineral provinces and geological basin. These surveys have indicated new mineral occurrences in different geological terrains. Large amount of data collected in the field is finally submitted as report in the hard copy format as part of the annual field survey plan. It takes many years to complete the geochemical survey of a geological basin by several parties working on different aspects. Geographical Information System (GIS) facilitates input, editing and display of spatial data collected in various forms (location, traverses, and boundaries) and analyse in most efficient way. However, large amount of geochemical data collected from various sources poses several challenges to represent and analyse the data in a meaningful way. This paper addresses all such difficulties in handling unformatted inputs and most optimal method for display, analysis and integration of geological data from various sources.