3D Seismic Dataset Research Articles

Oil prospects in the Mozambique Channel: where incipient subduction meets passive margin

After several major gas discoveries made offshore Tanzania and northern Mozambique, the entire East Africa margin has been assumed to be a gas province. We present evidence for a new oil province along this margin based on an interpretation of Spectrum’s recently acquired modern Broadband 2D seismic data in the offshore Angoche/Mozambique Basin. The new seismic data lying south of the Rovuma Basin and across the Davie Ridge in the Mozambique Channel (Figure 1) are considered together with an integration with sea surface oil slicks identified on satellite imagery and other direct hydrocarbon indicators (DHIs). Understanding the nature and origin of crustal architecture in the Angoche Basin and Davie Ridge is a vital input to plate reconstruction, as well as enabling an assessment of petroleum potential. We discuss potential source rocks and variation in geothermal gradient in the region and evaluate various plays in the light of the new geological findings within the new Broadband 2D seismic dataset.

Rock Physics Models and Seismic Inversion in Reservoir Characterization, “MUN” Onshore Niger Delta Field

Rock Physics Modelling and Seismic Inversion were carried out in an Onshore Niger Delta Field for the purpose of characterizing a hydrocarbon reservoir. The aim of the study was to integrate rock physics models and seismic inversion to improve the characterization of a selected reservoir using well-log and 3D seismic data sets. Seven reservoir sands were delineated using suite of logs from three wells. In this study, the sand 4 reservoir was selected for analysis. The result of petrophysical evaluation shows that the sand 4 reservoir is relatively thick (62 ft) with low water saturation (0.33), shale volume (0.11) and high porosity (0.32). These results indicate reservoir of good quality and producibility. Cross-plot of property pairs (acoustic impedance (Ip) vs. lambda-rho (λρ) and mu-rho (μρ) vs. lambda-rho (λρ) color-coded with reservoir properties reveals three distinct probable zones: hydrocarbon sand, brine sand and shale. Results show that low Ip, λρ and μρ associated with hydrocarbon charged sands correspond to low Sw and Vsh and high &#216. The integration of rock physics models and inverted rock attributes effectively delineated and improved understanding of already producing reservoirs, as well as other hydrocarbon charged sands of low Sw, Vsh, and high &#216 to the east of existing well locations, which indicate possible by-passed hydrocarbon pays. The results of this work can assist in forecasting hydrocarbon prospectivity and lessen chances of drilling dry holes in MUN onshore Niger delta field.

Repeatability of high-resolution 3D seismic data

High-resolution 4D (HR4D) seismic data have the potential for improving the current state-of-the-art in detecting shallow ([Formula: see text] below seafloor) subsurface changes on a very fine scale (approximately 3–6 m). Time-lapse seismic investigations commonly use conventional broadband seismic data, considered low to moderate resolution in our context. We have developed the first comprehensive time -lapse analysis of high-resolution seismic data by assessing the repeatability of P-cable 3D seismic data (approximately 30–350 Hz) with short offsets and a high density of receivers. P-cable 3D seismic data sets have for decades been used to investigate shallow fluid flow and gas-hydrate systems. We analyze P-cable high-resolution 4D (HR4D) seismic data from three different geologic settings in the Arctic Circle. The first two are test sites with no evidence of shallow subsurface fluid flow, and the third is an active seepage site. Using these sites, we evaluate the reliability of the P-cable 3D seismic technology as a time-lapse tool and establish a 4D acquisition and processing workflow. Weather, waves, tide, and acquisition-parameters such as residual shot noise are factors affecting seismic repeatability. We achieve reasonable quantitative repeatability measures in stratified marine sediments at two test locations. However, repeatability is limited in areas that have poor penetration of seismic energy through the seafloor, such as glacial moraines or rough surface topography. The 4D anomalies in the active seepage site are spatially restricted to areas of focused fluid flow and might likely indicate changes in fluid flow. This approach can thus be applied to detect migration of fluids in active leakage structures, such as gas chimneys.

Derivation of refraction statics solution for 3D seismic data in an onshore prospect Niger Delta field

The near-surface imaging and characterization of an onshore prospect field in the Niger Delta was successfully carried out in a previous study (Adizua et al. 2019) using an integrated approach of combining inversion of refracted arrivals and uphole measurements. The output of that study which revealed the layer characteristics of the near-surface (0–500 m) over the prospect field is now being used as a starting model to derive a complete refraction statics solution to be adapted for processing the 3D seismic dataset from the prospect field. The complete statics solution derived included the field or datum statics, refraction statics, and the 1st and 2nd residual statics which addressed the unresolved and remnant spatial long and short wavelength statics effect on the traces across the investigated field. The comprehensive solution was then incorporated into a PROMAXTM routine and applied to the seismic datasets using appropriate flow commands to perform the statics correction procedure. The outcome of the derived and implemented statics correction was demonstrated on shot gathers from the field in FFID configuration. Results from the several shot gathers analyzed after the application of the statics correction across the field showed that traces were adjusted back to their appropriate positions. The reflectors became better aligned and assumed a near-hyperbolic pattern which is a positive indication that the derived and applied refraction statics solution was the most appropriate for the dataset.

Accelerating geostatistical seismic inversion using TensorFlow: A heterogeneous distributed deep learning framework

Geostatistical seismic inversion is one of emerging technologies in reservoir characterization and reservoir uncertainty quantification. However, the challenge of intensive computation often restricts its application in practical studies. To circumvent the computational limitation, in this work, we present a distributed parallel approach using TensorFlow to accelerate the geostatistical seismic inversion. The approach provides a general parallel scheme to efficiently take advantage of all the available computing resources, i.e. CPUs and GPUs: the computational workflow is expressed and organized as a Data Flow Graph, and the graph can be divided into several sub-graphs which are then mapped to multiple computing devices to concurrently evaluate the operations in them. The high-level interface and the feature of automatic differentiation provided by TensorFlow also makes it much easy for users to implement their algorithms in an efficient parallel manner, and allows employing programs on any computing platform almost without alteration. The proposed method was validated on a 3D seismic dataset consisting of 600 × 600 × 200 grid nodes. The results indicate that it is feasible to the practical application and the computational time can be largely reduced by using multiple GPUs.

Volcanics: A Commonly Underestimated part of Petroleum Exploration

Conventionally, there has been an entrenched aversion to explore oil and gas in regions with volcanic geology. In other words, petroleum systems affected by igneous geology have not been considered with substantial oil and gas discoveries. However, the presence of volcanics is well known in many petroleum basins although not published in great details (including the North West Shelf of Australia), and there has been an increase in the number of hydrocarbon discoveries in volcanic basins worldwide. On the other hand, there has been volcanics geology factor associated with unsuccessful exploration wells. In the NWS of Australia, explorers care about the evidences as several unsuccessful wells, widely distributed in the area, have penetrated volcanics within the Triassic-Jurassic succession, which indicates a significant exploration risk. A primary purpose in writing this article was to illustrate that the presence of volcanics and their impacts on sedimentary rocks may lead to complex overprints for oil and gas exploration. Several 2D and 3D seismic datasets in addition to well information, from Barcoo Sub-basin of the NWS of Australia, were analysed and interpreted to demonstrate the fact that features we sometimes get with volcanics can be very misleading for hydrocarbon exploration. Volcanic rocks within the Triassic-Jurassic succession at the NWS of Australia are not considered favourable conditions for hydrocarbon accumulation. It is therefore important to develop an approach to better understand their impact on petroleum system and derisk prospects for exploration.

Full-volume interpretation methods: Applications for quantitative seismic stratigraphy and geomorphology of the Lower Barrow Group, Northwest Australia

Following decades of technological innovation, geologists have now access to extensive 3D seismic datasets. How these data will help understanding the complexity of the subsurface relies on developing stratigraphic workflows that allow very high-resolution interpretation in a cost-effective timeframe. Here, the use of full-volume, semi-automatic horizon tracking tools allowed interpreting ultra-high resolution seismic sequences (^0,000 yrs duration) within a Cretaceous prograding shelf-margin (Lower Barrow Group; LBG) on the North West Shelf of Australia. Initially, semi-automated horizon tracking allowed mapping key regional unconformities defining 3rd order seismic sequences. In a second step, a very high resolution grid (nodes corresponding to seismic traces) was generated in each 3rd order sequence. An automatic propagation algorithm then linked the nodes based on their similarities, resulting in a very dense network of “proto”-seismic horizons. Volume interpolation resulted in the creation of a Relative Geological Time (RGT) model from which a very high number of chronostratigraphic surfaces were extracted. This allowed a full volume 3D mapping of every clinoform in each 3rd order sequence, from which quantitative data (clinoform height, slope, topset vs bottomset thickness) and seismic attributes (seismic geomorphology) were extracted. This analysis unveiled the high resolution changes in sediment supply and accommodation in time and space in the LBG, and provided new insights on the distribution of shallow and deep marine plays in the basin. This innovative workflow constitutes a new step in sequence stratigraphy as it allows interpreters to map sequences in a true 3D environment hence taking into account the full variability of depositional systems in time and space.

Evolution of “Tres Hombres” - A Mid-crustal Dome Structure within the Jurassic Northern Beagle Sub-basin Western Australia: An Integrated Geophysical Investigation

The Tres Hombres structure is a large mid-crustal structural feature that that underlies the Permian – Late Jurassic mega-sequences of the Northern Beagle Sub-basin, Western Australia. Originally identified on regional 2D seismic lines, the Tres Hombres structure has now, for the first time, been fully imaged by high quality, deep record modern 3D seismic data. The area is also covered by gravity and magnetic datasets which were acquired together with the 3D seismic survey. Seismic mapping reveals a dome-like structure with a diameter of more than 30km, and with vertical relief of over 5km. This paper integrates seismic and potential fields datasets to explore the origins of this intriguing structure. Mechanisms considered for the emplacement of this feature include; basement cored compression, reactivated extensional basement faulting, remnant Palaeozoic topographic relief, salt-related diapirism, or plutonic/igneous intrusive activity. The actual mechanisms responsible for the evolution of Tres Hombres have obvious implications for adjacent and overlying petroleum systems within the Beagle Sub-basin. Detailed mapping of new 3D seismic datasets enables structural and stratigraphic restorations to be generated, which provide valuable insights into the timing of the Tres Hombres feature. Variations in the thicknesses of overlying sequences show the influence that this structure had on the stratigraphic evolution of the basin. Gravity and magnetic datasets have also been integrated into this study, and provide valuable controls on potential lithologies within the core of the Tres Hombres feature. These in turn have important implications as to the origin of this structure, and relationships to the tectonic evolution of the Beagle Basin.

Interpretation Using Explicitly Encoded Phase, Amplitude and Fault Data

Current horizon interpretation techniques are based primarily on the use of seismic reflectivity. While there have been robust algorithms developed to work with seismic data, there are limitations and trade-offs with each of these approaches. In this presentation we investigate the merits of interpretation based on the use of a colour blend comprised of phase, amplitude and fault datasets. The colour blend used in this workflow is a Hue-Saturation-Value (HSV) blend. In this blend the hue/colour is controlled by the instantaneous phase, the saturation is controlled by the amplitude, and the value/blackness is controlled by a fault detect volume. Combining these three datasets provides a greater level of explicit information when interpreting an event. In standard cases this information can be inferred by the interpreter using secondary attribute volumes, or an autotracking algorithm performing extra calculations in the background. However, both of these approaches add extra overhead to the work being performed, reducing efficiency. Explicitly encoding phase, amplitude and fault information allows: · Reduced incidence of cycle skipping · The ability to pick on a particular phase angle · Honouring of faults in autotracking · Increased visual information in manual interpretation. These points will be reviewed through the interpretation of a number of 3D seismic datasets, with varying data quality and covering a range of geological settings.

Investigation of Possible Shallow Gas Accumulations Associated with Pockmarks on the Otago Slope Southeast of New Zealand

High-resolution ‘boomer’ seismic data, together with an industrial 3D seismic dataset indicate the possible presence of shallow gas in the vicinity of the Waitaki Canyon, SE of New Zealand’s South Island. Crescent-shaped seafloor depressions are abundant on the marginal extent of the Otago canyon system in water depths between 500 and 1100 m. Fluids seeping through the seabed, potentially forming pockmarks, play a crucial role in seabed ecological systems and can be used to investigate the distribution of hydrocarbons in underlying geological units. Recently acquired 3D seismic data in the Canterbury frontier basin exhibit the first indications of shallow gas in the region. Two areas with shallow high-amplitude reversed phase reflections were identified and targeted for a high-resolution 2D seismic survey. The 2D data, acquired by the University of Otago in 2017, show reduced amplitudes beneath the bright spots (as also observed in the 3D data). Above the bright spots, bathymetry data show crescent-shaped seafloor depressions, which were most likely modified by northward flowing currents. Both recent and buried seafloor depressions along the shelf exhibit the same northward facing crescent form that we associate with water current modification. Water column imaging data reveal no evidence for present-day seepage of gas through the seabed. An ongoing programme of 2D seismic and bathymetry data collection is underway. High-density velocity analysis and amplitude variations with offset (AVO) will be assessed around the bright spots using several in- and crosslines from the 3D data.

Three-dimensional geosteering coherence attributes for deep-formation discontinuity detection

Deep-formation oil/gas exploration is a key objective in the geophysical field, and structural and stratigraphic discontinuities, such as faults and channels, usually contribute to the construction of traps and reservoirs. Coherence has been used successfully to identify these abnormal features in seismic amplitude volumes. However, the current coherence algorithms seldom involve the geologic concept. We propose geosteering coherence attributes by implementing the coherence calculation perpendicular to the direction of the structural trend in a 3D curved plane. We estimate a group of time lags between the original analysis trace and each original neighboring trace along a certain spatial direction by using dip scanning. For each spatial direction, we subsequently construct two new model traces by weighting phase traces derived from the complex seismic traces, in which time lags are eliminated. We then use the new model traces to compute the crosscorrelation coefficients for each spatial direction. We finally obtain the 3D geosteering coherence attributes by taking the minimum values among the modulus of the crosscorrelation coefficients along different spatial directions to approximately characterize the coherence perpendicular to the structural trend in a 3D curved plane. An example of the 3D physical modeling involving fracture groups and faults embedded in the deep formation is used to demonstrate the effectiveness of the 3D geosteering coherence attributes. The applications on two real 3D seismic data sets of sand reservoirs from western deep formation illustrate that our method can alleviate the influence of dipping strata and can highlight subtle structures. Compared to the conventional coherence method, our method can highlight subtle geologic structures more and better, suggesting that it may be serve as a future tool for detecting the distribution of geologic abnormalities in deep exploration.

Reconstruction of 3D non-uniformly sampled seismic data along two spatial coordinates using non-equispaced curvelet transform

Seismic data acquisition often faces the challenge of non-uniformly sampled data with missing traces. Only a few existing multitrace reconstruction methods can natively handle non-uniformly sampled data with missing traces. In this paper, we propose the non-equispaced fast discrete curvelet transform (NFDCT)-based reconstruction method designed for 3D seismic data that are non-uniformly sampled along two spatial coordinates. By partitioning 3D seismic datasets into time slices along source-receiver coordinates, we introduce 2D non-equispaced fast Fourier transform in the conventional fast discrete curvelet transform and formulate a regularised inversion of operator that links the uniformly sampled curvelet coefficients to non-uniformly sampled data. Numerically, the uniform curvelet coefficients are calculated by solving the L1-norm problem via the spectral projected-gradient algorithm. With the uniform curvelet coefficients, the NFDCT is formed via the conventional inverse curvelet transform and is used to reconstruct 3D non-uniformly sampled seismic data along two spatial coordinates. At the hand of reconstructed results from synthetic and field data, we demonstrate that the proposed method shows significant improvement over the conventional anti-leakage Fourier transform-based reconstruction method. The method we propose, which has a strong anti-aliasing and anti-noise ability, can be used to reconstruct the subset of observed data to a specified uniform grid along two spatial coordinates.

Characterization of a fractured basement reservoir using high-resolution 3D seismic and logging datasets: A case study of the Sab'atayn Basin, Yemen.

The Sab’atayn Basin is one of the most prolific Mesozoic hydrocarbon basins located in central Yemen. It has many oil producing fields including the Habban Field with oil occurrences in fractured basement rocks. A comprehensive seismic analysis of fractured basement reservoirs was performed to identify the structural pattern and mechanism of hydrocarbon entrapment and reservoir characteristics. A 3D post-stack time migration seismic cube and logging data of 20 wells were used and several 2D seismic sections were constructed and interpreted. Depth structure maps were generated for the basement reservoir and overlying formations. The top of the basement reservoir is dissected by a set of NW-SE step-like normal faults (Najd Fault System) and to a lesser extent, by secondary NNE-SSW oriented faults (Hadramauwt System). The Najd Fault System is dominant and dissects the reservoir in the middle of the field into two prospective uplifts. The northern and northeastern areas constitute the deep-seated downthrown side of the reservoir. Hydrocarbon emplacement is through the fault juxtaposition of the fractured basement against the organic shale source rock of the overlying Madbi Formation. Hydrocarbons are hosted in basement horsts formed by fault-controlled blocks and overlain by the regional seal of the Sab’atayn Formation. The basement reservoir rock is mainly composed of granite, quartz-feldspar, weathered silica, and mica minerals. Fractures were identified from the outcrops, cores, image logs, and the petrophysical analysis. Hydrocarbon saturation was observed in the upper and middle parts of the reservoir, more specifically in front of the highly fractured sections. The fracture porosity was less than 5% and the dead oil had an API gravity of 40° with no H2S or CO2. In conclusion, the structural highs of the Habban Field are of interest because most oil producing wells are drilled into them. We recommend extending the drilling and development activities in these uplifts.

Hybrid turbidite–contourite systems of the Tanzanian margin

Extensive 3D seismic datasets acquired during exploration offshore southern Tanzania have revealed the complex architecture of two contrasting styles of hybrid turbidite–contourite deposits that formed in the Cretaceous (Albian–Early Campanian) and Paleogene (Paleocene–Oligocene). Both sequences are characterized by migrating channel-levee complexes, interpreted to record, and be diagnostic of, the synchronous interaction of eastward, downslope flowing turbidity currents and northerly, along-slope flowing contour currents. Flow stripping of the fine-grained suspended part of the turbulent flow by weak contour currents led to the formation of expanded levee-drifts on the northern (downstream) side of the channels, which prograded southwards (upstream), driving southwards migration of the turbidite channel axis. The difference in the architecture of the two successions is due to the variation in slope topography at the time turbidite activity commenced and the frequency of coarse clastic input into the basin. Cretaceous (Albian–Campanian) turbidite systems were strongly controlled by the position of pre-existing contourite drifts and moats. The contorted geometry of the system provided loci for the deposition of Cretaceous reservoirs comprising thick, amalgamated channel deposits with a high net-to-gross ratio (N:G) and good vertical connectivity, and intra-slope fans with lower N:G and poor vertical connectivity. Paleogene turbidite channels initially evolved on a smooth slope. Sustained southward channel migration produced Paleogene reservoirs comprising complexly laterally-connected sheets of channel and lobe deposits above a southward-younging, diachronous compound unconformity. In both hybrid systems, contour current influence modified the geometry of the turbidite systems, resulting in temporal and spatial partitioning of the depocentres on the slope.

Common-focus point-based target-oriented imaging approach for continuous seismic reservoir monitoring

The ideal approach for continuous reservoir monitoring allows generation of fast and accurate images to cope with the massive data sets acquired for such a task. Conventionally, rigorous depth-oriented velocity-estimation methods are performed to produce sufficiently accurate velocity models. Unlike the traditional way, the target-oriented imaging technology based on the common-focus point (CFP) theory can be an alternative for continuous reservoir monitoring. The solution is based on a robust data-driven iterative operator updating strategy without deriving a detailed velocity model. The same focusing operator is applied on successive 3D seismic data sets for the first time to generate efficient and accurate 4D target-oriented seismic stacked images from time-lapse field seismic data sets acquired in a [Formula: see text] injection project in Saudi Arabia. Using the focusing operator, target-oriented prestack angle domain common-image gathers (ADCIGs) could be derived to perform amplitude-versus-angle analysis. To preserve the amplitude information in the ADCIGs, an amplitude-balancing factor is applied by embedding a synthetic data set using the real acquisition geometry to remove the geometry imprint artifact. Applying the CFP-based target-oriented imaging to time-lapse data sets revealed changes at the reservoir level in the poststack and prestack time-lapse signals, which is consistent with the [Formula: see text] injection history and rock physics.

Assessment of shallow subsea hydrocarbons as a proxy for leakage at offshore geologic CO2 storage sites

This study is part of a multi-phase effort to identify and characterize offshore geological carbon storage (GCS) potential along the Texas Gulf Coast. Previous efforts acquired a high-resolution 3D seismic dataset (P-cable™) and interpreted a seismically discontinuous zone as shallow gas pockets (<100 m below seafloor) associated with a vertical chimney structure. Our approach was to measure hydrocarbon concentrations and stable carbon isotopes near the seafloor to assess if gas migrated vertically from seismic anomalies. Deep-sourced thermogenic hydrocarbons would indicate that the structure is transmissive which could indicate an unacceptable risk for GCS at the site. Alternatively, hydrocarbons formed in-situ from biogenic processes would not preclude transmissivity of the structure but would add information to the risk assessment. Gases were extracted from 23 piston core samples recovered between 2.56 and 3.50 m subseafloor. Light hydrocarbons and stable carbon isotopes of methane were used for source attribution. The result was that geochemical signatures were consistent with typical background values observed within the first few meters of subsea sediment and therefore did not indicate leakage from depth. From our analysis, we offer insights into the use of hydrocarbon molecular and isotopic compositions at the seafloor for signal attribution as part of environmental assessments at geological CO2 storage sites.

High-resolution 3D seismic exhibits new insights into the middle-late Pleistocene stratigraphic evolution and sedimentary processes of the Bear Island trough mouth fan

Arctic Ocean trough mouth fans (TMFs) represent a valuable archive of glacial-interglacial sedimentary processes that are especially important when reconstructing pre-Weichselian glaciations that may lack distinct imprints on the shelves. In 2011, we acquired the first high-resolution 3D seismic cube (~3 m vertical and 6 m horizontal resolution) on the continental slope of the SW Barents Sea by use of a P-Cable 3D system, to study in detail the seismic stratigraphy and glacial depositional history of the Bear Island Trough Mouth Fan. This technology provides data with a resolution that, for the first time on the western Barents Sea slope, enables detailed mapping of deposits of different glacial cycles. The dataset provides entire spatially coverage, allowing us to reconcile multiple generations of glacigenic deposits and channel systems. High-resolution 3D seismic data is crucial to describe buried channels, glacial units, as well as low relief landforms such as sediment waves accurately. The 30 km2 seismic cube is located at the southern flank of the Bear Island TMF at water depths from 592 to 660 m where sandwaves dominate the present seafloor. The data covers the glacially derived stratigraphy in the uppermost ~700 m below the seafloor. We establish a robust stratigraphic framework by interpreting seismic reflectors along 2D tie-in lines to previously well-constrained seismic and well data. We find that our data provide a record of progradation of glacigenic debris flows (GDFs) since MIS 12 (0.5 Ma) to present. Horizon slices reveal a range of gullies and channels at different depths overlying the GDFs. We describe the paleoenvironment and sedimentary processes throughout this time-span (that covers seven glacial cycles) and discuss the impact of the Barents Sea Ice Sheet waxing and waning on erosion, sedimentation, and deposition along the continental slope. Abundant buried gullies were hitherto unknown at the Bear Island TMF, with previous work describing this succession as a debris-flow dominated unit where meltwater-related features are lacking, and interpreting this to represent low average temperatures. By use of the relatively small high-resolution 3D seismic dataset, we provide new evidence for the presence of gullies and channels indicating that periods of ice sheet melting and meltwater runoff existed throughout the middle-late Pleistocene succession. The work offers new insight into the stratigraphic evolution of a continental margin dominated by GDFs and demonstrates the value of high-resolution seismic, such as the P-Cable system, in resolving important details of paleo-slope-environments.

Seismic-driven geocellular modeling of fluvial meander-belt reservoirs using a rule-based method

A novel workflow is presented for building static models of fluvial reservoirs composed of large point-bar architectural elements, based on the application of a specialized forward stratigraphic model, named ‘Point-Bar Sedimentary Architecture Numerical Deduction’ (PB-SAND). The approach uses interpreted horizontal slices from 3D seismic datasets to reconstruct the planform evolution of meander loops, on which basis the geometry of point-bar deposits and associated accretion units can be simulated deterministically. The resulting meander-belt geometry is then populated with different types of facies, through a rule-based algorithm that generates facies architectures that reflect geologic understanding, enabling users to establish linkages between styles of meander evolution (e.g., meander growth via expansion, translation, rotation) and facies distributions. Input parameters define the proportions, geometries and distributions of types of point-bar deposits, as captured from subsurface data and/or from geologic analogs. Multiple stochastic realizations of facies architecture can be generated. To demonstrate the application of this modeling approach, the workflow has been applied to a meander-belt reservoir where large point-bar and channel-fill elements are imaged in seismic. A detailed example is used to illustrate workflows that can be used to build high-resolution sector models in pre-drill contexts, suitable for guiding development plans. An additional example is used to show how to achieve well match for densely drilled sectors, by means of a hybrid approach that combines the new algorithm with traditional geostatistical techniques. It is shown how the workflow allows consideration of point-bar growth styles, as inferred from seismic data, on distribution and geometry of heterogeneities, and how this facilitates the reproduction of geologic features that are important controls on the static connectivity of point-bar reservoirs (e.g., distribution and characteristics of bar-front mud drapes, and of mud-prone packages arising from progressive meander-bend tightening or from downstream fining of deposits beyond the apex of a meander bend). A comparison with traditional variogram-based methods is undertaken to compare metrics that describe intra-point-bar static connectivity and that represent proxies for the degree of compartmentalization of upper-bar sands by mud drapes.

Pliocene Deep Water Channel System of Celebes Molasse as New Exploration Play In Banggai Sula Foreland Basin, Eastern Sulawesi-Indonesia

Banggai-Sula foreland basin in Matindok block is the product of Late Miocene to Early Pliocene collision between Banggai-Sula microcontinent and East Sulawesi Ophiolite (ESO)-magmatic arc of Sundaland. Proven petroleum system plays for Donggi, Senoro, and Matindok gas fields are Miocene build-up carbonate and platform carbonates related to wrench structures, sealed by Plio-Pleistocene Celebes Molasse consists of conglomerate, conglomeratic sandstone, shale and charged during early Pliocene related to collisional tectonic from Miocene marine clastic source rocks. Latest interpretation of 3D & 2D seismic datasets on onshore area of Matindok block shown that there is possibility of NE to SW trending channel systems existed in Plio-Pleistocene Celebes Molasse as post collision sediments. Based on biostratigraphy interpretation, Celebes Molasse interval was deposited in marine environment, generally outer sublittoral to upper bathyal. Channel filled pattern on seismic data expression shown onlap, divergent and mounded-onlap fills on 6 (six) interpreted channel bodies. Fining upward sequences is well recognized based on gamma ray log from several wells that penetrated those interpreted channel. The thicknesses of channel bodies vary from 50 m to 150 m with sand to shale ratio up to 40 % and gas composition reading from C1 to C3. Despite of there is no well testing data on these channels interval; we believed that this Pliocene deep water channel can become the new exploration play although several studies about seal effectiveness of channel bodies as stratigraphic traps, lateral and vertical migration pathways need to be carried out.

Hydrothermal vents and seismic anomalies: implications for the petroleum system NE of Shetland

The influence of igneous intrusions and their associated vent complexes on hydrocarbon migration is poorly understood, yet may be significant in the exploration of petroleum basins located on passive margins. A regional review of the northeasternmost frontier sector of the UK Continental Shelf (UKCS) encompassing the southern extent of the Møre Basin has revealed evidence of extensive vent formation during the Late Paleocene. Anomalous seismic amplitude events that have not been previously described in this area are identified above and clearly related to several of the vent complexes, and a number of scenarios are postulated to explain their presence. Integrating existing geological studies and regional seismic interpretation with a new 3D seismic dataset reveals a close relationship between sills, vents and seismic anomalies which may be related to the presence of gas/fluid. Recognition of the vent complexes as potential fluid conduits long after initial formation may be important in focusing migration to younger stratigraphic levels. Important observations are made regarding a link to possible hydrocarbon migration mechanisms within the study area and the associated implications for hydrocarbon exploration and risking within this petroleum basin are investigated.