Seismic 3D Research Articles

Combining 3D seismics, eyewitness accounts and numerical simulations to reconstruct the 1888 Ritter Island sector collapse and tsunami

The 1888 Ritter Island volcanic sector collapse triggered a regionally damaging tsunami. Historic eyewitness accounts allow the reconstruction of the arrival time, phase and height of the tsunami wave at multiple locations around the coast of New Guinea and New Britain. 3D seismic interpretations and sedimentological analyses indicate that the catastrophic collapse of Ritter Island was preceded by a phase of deep-seated gradual spreading within the volcanic edifice and accompanied by a submarine explosive eruption, as the volcanic conduit was cut beneath sea level. However, the potential impact of the deep-seated deformation and the explosive eruption on tsunami genesis is unclear. For the first time, it is possible to parameterise the different components of the Ritter Island collapse with 3D seismic data, and thereby test their relative contributions to the tsunami. The modelled tsunami arrival times and heights are in good agreement with the historic eyewitness accounts. Our simulations reveal that the tsunami was primarily controlled by the displacement of the water column by the collapsing cone at the subaerial-submarine boundary and that the submerged fraction of the slide mass and its mobility had only a minor effect on tsunami genesis. This indicates that the total slide volume, when incorporating the deep-seated deforming mass, is not directly scalable for the resulting tsunami height. Furthermore, the simulations show that the tsunamigenic impact of the explosive eruption energy during the Ritter Island collapse was only minor. However, this relationship may be different for other volcanogenic tsunami events with smaller slide volumes or larger magnitude eruptions, and should not be neglected in tsunami simulations and hazard assessment.

Surface Wave Tomography of Northeastern Tibetan Plateau Using Beamforming of Seismic Noise at a Dense Array

AbstractIn traditional surface wave tomography based on seismic noise, 2D phase or group velocity distribution is obtained by performing pure‐path inversion after extracting interstation velocities based on the noise cross‐correlation function. In this paper, we show that 2D surface wave phase velocity maps of adequate quality can be obtained directly, without interferometry, by beamforming the ambient noise recorded at array of stations. This method does not require a good azimuthal distribution of the noise sources. The 2D surface wave phase velocity map is obtained by moving the subarrays within a larger dense network of stations. The method is illustrated with seismic noise recorded by over 600 stations of the ChinArray (Phase II). We obtain 2D Rayleigh wave phase velocity maps between 7 and 35 s in Northeastern (NE) Tibetan Plateau and adjacent regions that compare well with results obtained with other methods. The shear wave velocity model is then derived by inverting the phase velocity with depth. The model correlates well with geology and tectonics in NE Tibet. Two clear mid‐to‐low crustal low‐velocity zones are observed at 15‐ to 35‐km depth beneath the Songpan‐Ganzi terrane and Northwestern Qilian Orogen, possibly facilitating lower crustal flow in this key region for the tectonic evolution of NE Tibet.

Kinematic and mechanic evolution of the Andes buried front at the Boomerang Hills hydrocarbon province (Bolivia): Control exerted by the pre-Andean history

Abstract The Boomerang Hills are a hydrocarbon-rich region located in front of the Bolivian Andes, central South America, where the Andean chain bends forming the Bolivian Orocline. The geological interpretation of seismic (2D profiles and 3D volumes) and well data allowed us to generate a complete stratigraphic section, cross sections, maps and a 3D model, and to obtain the parameters to carry out a depth conversion and decompaction. A cross section and a 3D model were kinematically and mechanically restored, as well as decompacted, to decipher the evolution of this region through time. The southern Boomerang Hills are the buried frontal part of the Andes where thin-skinned contractional structures of Andean age (Late Cenozoic) predominate, whereas the northern Boomerang Hills belong to the Beni-Chaco Plain, where contractional structures are almost absent and thick-skinned extensional tectonics of pre-Andean age (Paleozoic, Mesozoic and Early Cenozoic) dominate. The buried frontal thrust of the Andes resulted from transpressional reactivation of a gravity-driven, extensional detachment developed along the slope of a basement high tilted during Paleozoic times. Thus, the thrust orientation, position, dimensions and type of structural termination were controlled by the extensional fault geometry, the Paleozoic mechanical stratigraphy, and the structural relationships between the Paleozoic cover and the basement.

The Application of 4D Seismic in Niger Delta Basin: A Review

Time-lapse seismic also known as 4D seismic is one of the advanced techniques employed in the oil and gas industry for petroleum production management and monitoring for over 20years. It involves carrying out two or more 3D seismic at different calendar times, before and after production over the same reservoir. We present advances in Time Lapse 3D seismic (also known as 4D seismic) and its application in the Niger Delta basin of Nigeria. Over the years, the technique has been used in Niger Delta to understand reservoir drainage performance, enable better well placement, identifying bypassed oil, detecting fluid communication, understanding of internal architecture of the reservoirs, and locating infill wells for future re-development. 4D seismic has demonstrated its potential and it is fast becoming a standard tool in the oil companies. DOI : 10.7176/APTA/83-05 Publication date: February 29 th 2020

Seismic horizon picking by integrating reflector dip and instantaneous phase attributes

Seismic horizons are the compulsory inputs for seismic stratigraphy analysis and 3D reservoir modeling. Manually interpreting horizons on thousands of vertical seismic slices of 3D seismic survey is a time-consuming task. Automatic horizon interpreting algorithms are usually based on the seismic reflector dip. However, the estimated seismic reflector dip is usually inaccurate near and across geologic features such as unconformities. We are determined to improve the quality of picked horizons using multiple seismic attributes. We assume that seismic horizons follow the reflector dip and that the same horizons should have similar instantaneous phase values. We first generate horizon patches using a reflector dip attribute, which is similar to current methods. We use seismic coherence attribute as the stop criteria for tracking the horizon within each patch. Considering the inaccuracy of reflector dip estimates at and near the discontinuous structures such as fault and unconformities, we use the seismic instantaneous phase attribute to improve the quality of the generated horizon patches. We generate horizons by merging the residual horizon patches and only outputting the best horizon in each iteration. Our method is capable of generating a horizon for each reflection within the 3D seismic survey, and the generated horizons strictly follow the seismic reflections over the whole seismic survey. Finally, each time sample of seismic traces is assigned a chronostratigraphic relative geologic time value according to the tracked horizons.

The Blake Field, Blocks 13/24a and 13/29b, UK North Sea

Abstract The Blake Field is subdivided into two discrete parts, the ‘Channel’ and the ‘Flank’ areas. The two areas are geologically different but also reflect the different levels of maturity in terms of their development. Blake Channel was discovered in 1998, with first production commencing in 2001. Blake Flank was discovered in 1974 and developed in 2003. The field contains saturated light oil, with a field-wide oil–water contact and two significant gas caps. The reservoir comprises deep-water turbidite sands of Lower Cretaceous age. The combination of complex depositional environment and dynamic data resulted in the decision in 2016, to create a new model incorporating a fully integrated approach to subsurface evaluation and modelling. The latest work summarized in this paper incorporates a new geological interpretation along with the addition of aquifer extensions to capture depletion from offset fields, and a palaeo-oil leg, to help limit aquifer influx and improve history match. 4D seismic has also been incorporated to support the evaluation. Blake Channel and Flank have oil-in-place of 230 MMbbl and 300 MMbbl and have produced 94 MMbl and 15 MMbbl, respectively, to date.

A complete workflow applied on an oil reservoir analogue to evaluate the ability of 4D seismics to anticipate the success of a chemical enhanced oil recovery process

In an Enhanced Oil Recovery (EOR) process, one of the main difficulties is to quickly evaluate if the injected chemical products actually improve oil recovery in the reservoir. The efficiency of the process can be monitored in the vicinity of wells, but it may take time to estimate it globally in the reservoir. The objective of this paper is to investigate the ability of 4D seismics to bridge this gap and to help predict the success or breakdown of a production strategy at reservoir scale. To that purpose, we consider a complete workflow for simulating realistic reservoir exploitation using chemical EOR and 4D seismic modeling. This workflow spans from geological description to seismic monitoring simulation and seismic attributes analysis, through geological and reservoir modeling. It is applied here on a realistic case study derived from an outcrop analog of turbiditic reservoirs, for which the efficiency of chemical EOR by polymer and surfactant injection is demonstrated. For this specific field monitoring application, the impact of both waterflooding and proposed EOR injection is visible on the computed seismics. However, EOR injection induces a more continuous water front that can be clearly visible on seismics. In this case, the EOR efficiency can thus be related to the continuity of the water front as seen on seismics. Nevertheless, in other cases, chemical EOR injections may have more moderate impacts, or the field properties may be less adapted to seismic monitoring. This points out the importance of the proposed workflow to check the relevance of seismic monitoring and to design the most adapted monitoring strategy. Numerous perspectives are proposed at the end of the paper. In particular, experts of the different disciplines involved in the proposed workflow can benefit from the availability of a complete set of well-controlled data of various types to test and improve their own tools. In contrast, the non-experts can easily and quickly benefit from “hands-on” experiments for understanding the involved phenomena. Furthermore, the proposed workflow can be directly applied to geological reservoirs all over the world.

НОВЫЙ МЕТОДИЧЕСКИЙ ПОДХОД К ОЦЕНКЕ ХАРАКТЕРИСТИК ПАЛЕОРУСЛОВЫХ ТЕЛ ПО РЕЗУЛЬТАТАМ АТРИБУТНОГО АНАЛИЗА В РАЗЛИЧНЫХ ГЕОЛОГИЧЕСКИХ УСЛОВИЯХ

The paper presents the results of studying the characteristics of paleochannel targets using seismic (3D) and well data based on the use of dynamic attributes. The paper demonstrates methodological approaches to the application of seismic attributes in the pay interval. As a result, the applicability of various attributes for the selection of paleochannels was analyzed. Effective thicknesses of the central channel, identified by attributes, were determined based on the spectral decomposition of the peak frequency. The results obtained are consistent with those obtained using well data based on geostatistical analysis. The methodological approach presented in the paper can be used in various oil and gas regions.

Vision‐Based Three‐Dimensional Reconstruction and Monitoring of Large‐Scale Steel Tubular Structures

A four‐ocular vision system is proposed for the three‐dimensional (3D) reconstruction of large‐scale concrete‐filled steel tube (CFST) under complex testing conditions. These measurements are vitally important for evaluating the seismic performance and 3D deformation of large‐scale specimens. A four‐ocular vision system is constructed to sample the large‐scale CFST; then point cloud acquisition, point cloud filtering, and point cloud stitching algorithms are applied to obtain a 3D point cloud of the specimen surface. A point cloud correction algorithm based on geometric features and a deep learning algorithm are utilized, respectively, to correct the coordinates of the stitched point cloud. This enhances the vision measurement accuracy in complex environments and therefore yields a higher‐accuracy 3D model for the purposes of real‐time complex surface monitoring. The performance indicators of the two algorithms are evaluated on actual tasks. The cross‐sectional diameters at specific heights in the reconstructed models are calculated and compared against laser rangefinder data to test the performance of the proposed algorithms. A visual tracking test on a CFST under cyclic loading shows that the reconstructed output well reflects the complex 3D surface after correction and meets the requirements for dynamic monitoring. The proposed methodology is applicable to complex environments featuring dynamic movement, mechanical vibration, and continuously changing features.

Methods of determination of spatial distribution of minor-amplitude faults and fissures in thin-layered coal-bearing geological medium

A problem of determining location of faults and fissured in geological medium which appear in the process of formation of the main types of geological structures: shears, nappes, faults, grabens, axes of folding and compression zones is considered. Areal seismic records of MCDP 3D obtained in the mine field of “Krasnolimanskaya” mine (Donetsk district) were used as initial data. It is located on the monocline of the southwestern part of Kalmius-Torets basin in the hanging wing of the Central nappe with amplitude up to 310m. Monocline occurrence of rocks is complicated by numerous disjunctive faults of the faulting type with amplitudes up to 95m. The main marker for identification for presence of a fault on the seismic records of MCDP 3D under conditions of horizontally-layered medium is interruption and (or) displacement of the axis of reflected waves phase synchronism. In some cases a diffracted wave appears in the place of horizon rupture. Provided that in the case of complicated geology it seems impossible to identify minor-amplitude displacements and discordant occurrence of reflecting margins related to faults. For spatial identification of the fault structures position the results of solving the inverse seismic problem are proposed – logarithmic decrements of fading (LDF) with their method of calculation that was put forward by the author previously. Temporal cross-sections of LDF have the same permissive ability as seismic data of MCDP 3D. Such a detail allows separating out minor-amplitude derangements related to faults and fissures. Special feature of temporal data of LDF is in the point that the identifiers of discordant occurrence of reflecting margins are their absorbing properties. The examples of vertical and horizontal LDF sections of a seismic cube 3D where a lot of deep and surface faults can be traced are given in the paper. Taking into account the complexity of mapping the planes of faults in three-dimensional space a method of automatic determination of the point of drastic change of absorbing properties of the medium (on each of horizontal cuts of the cube) with application of wavelet analysis has been proposed. A matrix of attributes is created of such points by which the planes of faults are plotted.

Identifying and predicting multiples based on spread of velocity spectrum

Abstract The genesis of internal multiples is complicated and identification is difficult as their velocities are similar to the velocity of primaries, so their residual time is short. The existing conventional methods for identifying multiples are mainly used on a single-common mid-point (CMP) or single line, so the result is indistinct and inaccurate. The concept of velocity spread is proposed, whereby multiples are identified by obtaining the lateral spread of energy clusters on the velocity spectrum. The proposed method uses image segmentation to binarise the velocity spectrum, obtain the spread of velocity, and identify and predict multiples on the plane via attribute spread slicing. In a 3D seismic of Sichuan, the multiples predicted are in good agreement with the known wells. The case shows that velocity spread analysis can quantitatively identify and predict multiples interference, and is complementary to the existing multiples identification method. It can be used to monitor the multiples suppression effect in seismic processing and analyse the interference of multiples in interpretation. In addition, the method has good practicability for evaluating the reliability of reservoir prediction results and reduces the risk of well location deployment during exploration.

Stratigraphy of Architectural Elements of a Buried Monogenetic Volcanic System

AbstractLarge volumes of magma emplaced and deposited within sedimentary basins can have an impact on the architecture and geological evolution of these basins. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D visualisation of igneous bodies has helped increase knowledge about the architecture of volcanic systems buried in sedimentary basins. Here, we present the complete architecture of the Maahunui Volcanic System (MVS), a middle Miocene monogenetic volcanic field now buried in the offshore Canterbury Basin, South Island of New Zealand. We show the location, geometry, size, and stratigraphic relationships between 25 main intrusive, extrusive and sedimentary architectural elements, in a comprehensive volcano-stratigraphic framework that explains the evolution of the MVS from emplacement to complete burial in the host sedimentary basin. Understanding the relationships between these diverse architectural elements allows us to reconstruct the complete architecture of the MVS, including its shallow (<3 km) plumbing system, the morphology of the volcanoes, and their impact in the host sedimentary basin during their burial. The plumbing system of the MVS comprises saucer-shaped sills, dikes and sill swarms, minor stocks and laccoliths, and pre-eruptive strata deformed by intrusions. The eruptive and associated sedimentary architectural elements define the morphology of volcanoes in the MVS, which comprise deep-water equivalents of crater and cone-type volcanoes. After volcanism ceased, the process of degradation and burial of volcanic edifices formed sedimentary architectural elements such as inter-cone plains, epiclastic plumes, and canyons. Insights from the architecture of the MVS can be used to explore for natural resources such as hydrocarbons, geothermal energy and minerals in buried and active volcanic systems elsewhere.

3C seismic data processing and interpretation: a case study from Carpathian Foredeep basin

Chałupki Dębniańskie seismic profile 2D–3C is located in Carpathian Foredeep basin, Poland, and is an object of interest for geologists and geophysicists due to the presence of gas-bearing layers. Multicomponent seismic plays a significant role in supporting reservoir analysis related to accumulations of crude oil and natural gas. The purpose of the research was the optimal processing workflow design, which integrated seismic images of three-component 2D seismic line (2D–3C seismic). A complete processing flow for vertical and both horizontal components was conducted to obtain stacks and prestack gathers with preserved amplitude relations (RAP processing). The main issue of the research was the interpretation of S-wave velocity, which was not provided by well log data. The obtained results increased the reliability of seismic interpretation within Chałupki Dębniańskie area. The research provided valuable information regarding amplitude anomalies and helped in the verification of the potential gas accumulations. Several reservoir analysis tools were tested, including seismic attributes and AVO analysis. Conducted research confirmed the existence of reservoir which is characterized by good reservoir parameters.

Integrated seismic attributes and stochastic inversion for reservoir characterization: Insights from Wadi field (NE Abu-Gharadig Basin, Egypt)

Sand-lithofacies distributions are a vital component of reservoir characterization and the generation of successful reservoir models. Through the integration of selected seismic attributes with post-stack stochastic seismic inversion reservoir distributions and architectures are accurately delineated for the Upper Cretaceous reservoir (Abu Roash “C”) in the Wadi field of NE Abu-Gharadig Basin, Egypt. Seismic interpretation and 3D structural modeling generate a regionally accurate image of the subsurface of Wadi field revealing a variety of structures: low-relief horsts and grabens, a faulted inversion-related anticline, normal and reverse faults (inverted basin phenomenon). Seismic attributes (second derivative and acoustic P-impedance) indicate that the Abu Roash “C” reservoir is characterized by the presence of two discrete sand-filled channels. The P-impedance attributes derived from post-stack seismic inversion utilized with the distributed petrophysical properties (density) predict the occurrence probability of the distinctive lithofacies in Abu Roash “C” reservoir. As stochastic seismic inversion provided an extensive vertical and lateral information set for the reservoir heterogeneity between wells, it was utilized as the definitive information requirement in generating the lithofacies models. The lithofacies obtained from integrating seismic attributes and inversion are calibrated with facies identified using well logs. The lithofacies model derived from this integrated approach provides an added geologic insight into the stratigraphic architecture and reservoir distribution and lessens exploration/development risk in the Wadi field. The resulting workflow is an effective tool for highlighting potential areas of better quality reservoir development, thereby demonstrating the value of this integrated approach.

Research on WebGL-based 3D Visualization Platform for Earthquake Rapid Reporting

In the era of big data, after the devastating earthquake, the amount of information required for earthquake emergency has increased geometrically. In order to display various geological, environmental and meteorological information more intuitively, network 3D visualization has become the Core technologies that were indispensable in terms of Geographic process dynamic simulation, visual analysis and synergistic decision. This paper introduced WebGL+HTML5 technology as the underlying development platform, ArcGIS API for JavaScript as the map access interface, and realized the WebGL-based seismic rapid report 3D visualization platform. The coordinate conversion algorithm has been used to realize the latitude and longitude coordinate offset algorithm, which solved the position error caused by the secondary encryption of Baidu map and Google map during positioning location. The 3D measurement function in ArcGIS API for JavaScript realized the display of the distance, area and attribute information in 3D environment, used ECharts and memory optimization technology to improve the browsing efficiency of the platform on the mobile terminal and optimize the display interface. The implementation of this system could provide technical and decision support for earthquake workers in earthquake emergency response.

Forensic mapping of seismic velocity heterogeneity in a CO2 layer at the Sleipner CO2 storage operation, North Sea, using time-lapse seismics

CO2 separated from natural gas produced at the Sleipner and Gudrun fields is being injected into the Utsira Sand, with around 18 million tons currently stored. Time-lapse 3D seismics have been deployed to monitor development of the CO2 plume. The 2010 seismic survey resolved, for the first time in 3D, the topmost CO2 layer into distinct reflections from its top and base. Seismic velocity is diagnostic of CO2 layer properties and a forensic interpretative approach is adopted to determine spatial velocity variation in the topmost CO2 layer. Velocity is obtained by equating absolute layer thickness, derived by subtracting a constructed flat CO2 – water contact from the topographical relief of the reservoir top, to the temporal separation of the layer top and base reflections, with appropriate correction for wavelet interference effects. Layer velocities show a systematic and robust spatial variation between a northern area with a mean velocity of 1371 ± 122 ms−1 and a central area with a much higher mean velocity of 1638 ± 103 ms−1. Recent fluid flow simulations of the topmost CO2 layer have shown that incorporating a high permeability channel in the model reservoir significantly improves the history-match. This high permeability channel corresponds remarkably closely to the low seismic velocities mapped in the northern area, with higher layer velocities of the central area interpreted as more argillaceous, less permeable overbank deposits. The new velocity analysis therefore provides independent support for including deterministic permeability heterogeneity in predictive fluid flow modelling of Sleipner.

Features of conducting of geological exploration on shale gas in Volyno-Podillia at the regional stage of studying

Features of structural conditions of occurrence, gas accumulation, lithofacies, petrophysical and geochemical parameters, shielding factor, character-bearing shale gas saturation are fundamentally different from traditional gas deposits. Stratigraphic shale formation considered as a potential gas deposit. Considering this specificity its allocation and mapping must be executed at an early stage. To delineate gas bearing shale formations of Volyno-Podillia and allocation the most perspective areas offered a complexation of regional seismic survey 2D for great depths (two longitudal profiles of north-western stretch as it continued from the Lublin basin in Poland and 5 crosssections from southwest to the northeast with its total length of about 1500 linear kilometers) with electric prospecting methods of different modifications, caused polarization, electromagnetic methods of regional seismic exploration grids profiles, large-scale atmogeochemical shooting and other direct methods. As the completion of regional stage must be drilling of vertical parametric pilot wells with solid coring from perspective shale strata, laboratory studies of organic matter, of katagenesis, lithofacies and mineralogical composition of shales, their petrophysical and geochemical properties, modeling and testing perspective shale strata using multistage hydrogaps. Prospects of further exploration and it’s complex based on the results geologic-economic evaluation of perspective of petrogas of the region and obtaining results of works start-up phase.

Hydrocarbon prospectively determination of “eagle field”, coastal swamp ii Niger delta.

Seismic and well log data were collected from onshore depobelt of Nigeria with a total of 1000 seismic lines and 3 wells. The main objective of the study was to determine hydrocarbon prospectivity and reserve estimates of the field. The evaluation centred on seismic interpretation and 3D visualisation (DHI detection) of the “Ejanla Field” 3D in total, Four horizons have been interpreted regionally for correlation purposes and three as prospect specific horizons. Four prospects and some, more speculative leads were identified in the area of which most are conventional three way dip/fault closures and some hanging wall closures. The potential for stratigraphic trapping was also recognized. The study showed that the small closure areas and limited hydrocarbon column lengths affected the number of prospects and at the shallow levels.The main risk to oil prospectivity in the area as revelled by the data interpretation is gas which may have resulted from the observed higher geothermal gradient in the deeper depth. Reservoir development and retention (overpressure) for prospects and leads in the deeper and more distal sedimentological settings form additional risks.

RESULTS OF INTERPRETATION OF SEISMIC SECTIONS DURING ENGINEERING SURVEYS WITHIN OF THE SOUTH-KIRINSKOYE OIL AND GAS CONDENSATE FIELD (SHELF OF SAKHALIN ISLAND)

High-resolution 2D seismic is the main and optimal method in marine engineering geophysics, which for many years has worked well for the production of semi-submersible drilling rigs, self-lifting drilling rigs, construction of berthing facilities and bridges. The main objective of this method is to identify near-surface gas, faults, which are geological hazards. The method used for performing marine research is longitudinal profiling of reflected waves with a 48-fold overlap of the reflecting horizons. To obtain high-quality seismic migrated sections, we have previously developed a unified data processing algorithm for the offshore areas of the South-Kirinskoye oil and gas condensate field (Sakhalin shelf). More than 8,000 line km of seismic data were processed. The article presents the sequence of interpretation, as well as an analysis of the presence of hazards in the project wells (objects). To isolate potentially dangerous objects for each horizon, a dynamic analysis was carried out, which included the definition of the following parameters: maximum and minimum peak amplitude. The systematization and classification of amplitude anomalies was carried out according to such features as a phase change, frequency reduction, the presence of a supply channel and distortion (false deflection) of all underlying boundaries, indicating the possible presence of gas. The probable hazard levels for drilling operations were determined. All the identified anomalies in the process of interpreting seismic sections were mapped to the geological hazards to select the optimal and safe installation point for drilling a prospecting or exploration well.

2D Seismic Imaging Improvement through Prestack Depth Migration (PSDM) Method

The quality of seismic is important for interpretation. Prestack Depth Migration produce better quality of seismic imaging. The seismic generated through PSDM method has better seismic reflector and geological structure appearance compared to Prestack Time Migration (PSTM) method. Accurate interval velocity modeling is a key in PSDM process, involving dix transformation, coherency inversion, and tomography. Comparison between PSTM and PSDM show that PSDM offer better imaging for interpretation because PSDM has better seismic reflector continuity and good geological appearance.