Seismic Survey

The ability to perceive biologically important sounds is critical to marine mammals, and acoustic disturbance through human-generated noise can interfere with their natural functions. Sounds from seismic surveys are intense and have peak frequency bands overlapping those used by baleen whales, but evidence of interference with baleen whale acoustic communication is sparse. Here we investigated whether blue whales (Balaenoptera musculus) changed their vocal behaviour during a seismic survey that deployed a low-medium power technology (sparker). We found that blue whales called consistently more on seismic exploration days than on non-exploration days as well as during periods within a seismic survey day when the sparker was operating. This increase was observed for the discrete, audible calls that are emitted during social encounters and feeding. This response presumably represents a compensatory behaviour to the elevated ambient noise from seismic survey operations.

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Concern is growing that marine fauna can be affected by noise such as naval sonar, pile driving or geophysical surveys, among others. Literature reports a variety of animal reactions to human noise (from apparently null or negligible to strong). However, conclusive results on its effects on marine mammals at individual and population level are still lacking. In 2015, the Italian Environmental Impact Assessment Commission mandated seismic operators apply a standard scientific protocol comparing marine mammal presence before, during, and after offshore seismic survey. For 60 days before and after the survey, marine mammals are monitored using visual and acoustic methods. One or more acoustic autonomous recorders, depending on area size, must also be deployed throughout the three phases for continuous monitoring. Consistent data gathered from many surveys will enable robust statistical analysis of results. Diffusion of this monitoring method internationally would improve the study of far-reaching, intense, low frequency noise.

A 2.4 km multicomponent seismic line was acquired near Calgary International airport to evaluate Vibroseis ® source and receiver parameters for recording P-S data. A series of source tests was undertaken using one and two vibrators, several different sweep lengths and frequency bandwidths. Linear as well as and non-linear sweeps were also evaluated. Reviews of the source tests indicated that 2 vibrators were required to obtain visible reflections from basement rocks (1.8 s P-P time). Optimum source characteristics for P-S data were found to be a non-linear sweep (-3 dB/octave) from 6 Hz to 100 Hz over 12 seconds. Vibrator separation was also tested in a 'walkaway' experiment to evaluate this source parameter on data quality. Conventional 3-C geophones as well as new '3-C nails' were also tested. One test line processed to date indicates P-P reflections with bandwidth over the full spectrum of the source sweep and P-S reflections with bandwidth from 6 Hz to approximately 60 Hz.

A high-resolution 3D seismic survey was undertaken to map shallow aquifers near Calgary, Alberta. The survey was 500 m x 300 m in area, with shot and receiver lines in an orthogonal geometry using 50 m line separation. Shots and geophones were spaced at 10m intervals along source and receiver lines, respectively. The surface source used was an 18,000 lb EnviroVibe sweeping over a 10 Hz to 180 Hz range. The survey yielded excellent reflections with a dominant frequency of 50 Hz. One high-amplitude eastdipping reflection, occurring between depths of 250 m and 450 m, was mapped over the survey area. The site is currently being reviewed for the development of a geophysical training centre.

Within the Gulf of Guinea high levels of fisheries-related cetacean mortality (bycatch and direct-capture) has been documented. For locally rare species such removals could potentially lead to significant population level effects. However, information on the cetacean abundance and distribution is scarce. Similarly, it remains largely unreported where fishing fleets operate offshore. A cetacean survey took place during geophysical surveys (2013-2014) along the coasts of Ghana and Côte d'Ivoire. This provided a unique opportunity to study both offshore cetacean and fishing communities. Due to large group-sizes, melon-headed whales were the most abundant (0.34 animals km −1) followed by Fraser's dolphins and short-finned pilot whales. Range state records were confirmed for melon-headed whale and Fraser's dolphin in Ivoirian waters and ten further species represented first at-sea sightings. The artisanal fishing canoe was most abundant (92% of all vessels) and recorded up to 99.5 km from the Ghanaian coast. Asian trawlers operated over shelf areas and tuna purse-seine vessels in deep oceanic and slope waters. Fraser's dolphins, melon-headed whales, pantropical spotted dolphins, bottlenose dolphins, and pilot whales were recorded in areas with the highest fishing densities. Melon-headed whales, pilot whales, and rough-toothed dolphins were observed in vicinity of trawlers; bottlenose dolphins, pantropical spotted dolphins, and pilot whales in vicinity of canoes. Some notable differences were found in the species composition between the present surveys and port-based surveys of landed cetaceans (bycatch/direct-captures). These may be explained by (1) feeding strategies (nocturnal vs. diurnal; surface vs. deep water); (2) different attractions to vessels/fishing gear; (3) variable body sizes; and (4) difficulty to positively identify species. Despite these differences, both cetaceans and fishing vessels predominantly occurred in shelf and slope waters (< 1000 m depth contour), making fishery-related mortality likely. The poor knowledge on population trends of cetaceans in this unique upwelling region, together with a high demand for cetacean products for human consumption (as "marine bushmeat") may lead to a potential decline of some species that may go unnoticed. These new insights can provide a foundation for the urgently required risk assessments of cetacean mortality in fisheries within the northern Gulf of Guinea.

The seafloor near Deep Sea Drilling Project Site 576 (study Area E£ has a strong northwest to southeast lineation, parallel to the strike of the Mesozoic magnetic lineations. High-resolution (3.5-kHz) seismic profiles show four prominent reflectors (R 2-R 5). Two strong, continuous reflectors (R 2 and R 3) overlie a semitransparent section. These reflectors correspond to an ~ 1.3 m.y. old volcanic ash and an ~7.2 m.y. old horizon. Reflector R 4 is a discontinuous reflector within the semitransparent section and is ~25 m.y. old. Reflector R 5 corresponds to ~70-m.y.-old carbonate turbidites in bathymetric lows and to pelagic carbonates or cherts in bathymetric highs. Isopach maps of all seismic intervals between these reflectors reveal local thinning and thickening and can be used to measure variations in sediment-accumulation rate. The local sediment distribution suggests that bottom water has flowed southeast or southwest across Area E 2 for the past 70 m.y. This direction is counter to the present net flow of the Pacific Bottom Water and may indicate the existence of a persistent local bottom gyre caused by bathymetric barriers to the west, north, and east of Area E 2. Dramatic thinning of all seismic intervals in the northeast corner of Area E 2 may be related to constricted Pacific Bottom Water accelerating through a gap in the barrier. Anomalous sedimentation suggests that the bottom currents were relatively sluggish from-25 to 7 m.y. ago. All seismic intervals reveal very small mass-wasting features; these features are more prevalent in intervals Ri~R 2 and R 4-R 5. The seafloor around Site 578 (study Area Bj) has an east-west lineation that also parallels Mesozoic lineations. The local relief is low, less than 80 m. High-resolution seismic profiles show several continuous, parallel reflectors that generally correspond to volcanic ash layers: Reflectors R 2 (-0.47 m.y. ago), R 3 (-0.97 m.y. ago), R 4 (-2.44 m.y. ago), R 5 (5-6 m.y. ago), and R 6. All reflector intervals increase dramatically (roughly 10 times) in thickness over a south-north distance of only 80 km. This abrupt increase appears to mark a major boundary separating a province with uniformly high sedimentation rates (typically about 50 mm/1000 yr. in the upper intervals) to the north from a large province with relatively low sedimentation rates (typically about 5-10 mm/1000 yr.) to the south. The sedimentation boundary has remained virtually stationary for ~ 6 m.y. and perhaps for more than 20 m.y. Although the sharpness and spatial stability of the boundary remain an enigma, we believe that the sedimentation boundary is the consequence of bottom-water flow modulating an otherwise more gradual north-south sedimentation gradient. South of Area B^ sedimentation anomalies indicate that the Pacific Bottom Water flows north or northwest, but within Area Bj, sedimentation variations suggest an eastward flow. A period of higher velocity flow between ~ 2.44 and 5-6 m.y. ago (R4-R5 times) is consistent with results from Area E 2 , indicating that bottom-water velocity has also apparently increased there since ~ 7 m.y. ago.

To complement a 3D High Resolution streamer survey, Total E&P operated in 2008-2009 a large 3D Ocean Bottom Node (OBN) acquisition to monitor a hydrocarbon reservoir in deep offshore Angola. Mirror node imaging has already proved to be more appropriate for reconciliation with streamer data, but positioning and timing issues as well as azimuthal coherent stacking of data need to be solved to better preserve the high frequency content of data. In this paper we show results obtained with a method for estimating time statics for nodes deployed in a deep offshore environment. Secondly we show that the concept of Offset Vector Binning using hexagonal tiles is applicable to this node data acquisition. Mirrored data migration in Common Offset Vector domain provides Common Imaged Gathers with preserved offset and azimuthal information, which enables a better stacking of information at all offsets and azimuths.

A high-resolution seismic survey was performed on the Lagoa dos Patos, southern Brazil. The survey was conducted aboard the research vessel LARUS of the Fundação Universidade Federal do Rio Grande. The seismic profiles were obtained using a 3.5 kilohertz frequency, which provided a rather good penetration depth and resolution of the records. Results of the seismic records allowed the determination and mapping of seismic facies and seismic sequences, as well as related architectural elements, which were identified basically through the configuration patterns of the seismic reflectors. The analysis of the seismic records allowed the identification of the architectural elements that build up the sedimentary pile accumulated in the coastal prism of the State of Rio Grande do Sul, contributing to a better understanding of the geological evolution of the southern Brazilian coastal plain during the Quaternary period.

The geological evolution of the continental shelf and in the coastal zone of southern Brazil during the Quaternary period is addressed in this study. High-resolution seismic records obtained at the Patos Lagoon revealed the presence of channels that deeply dissected the coastal zone before the formation of the modern, low-relief, coastal plain. Two periods of channel incision are inferred, based mainly on seismic records. The paleodrainage paths mapped from the seismic records can be connected with those recognized by previous studies on the adjacent continental shelf and slope. Upstream, the drainage incised mainly into the coastal prism deposited during previous sea-level highstand events. The paleodrainage network, recognized on the coastal plain and continental shelf, represents a river-shelf system, linking the drainage basin to the depositional settings on the marginal basin, bypassing the continental shelf exposed during a forced regression event. The drainage incised into th...

CALICHE DEPOSITS IN THE ZECHSTEIN LIMESTONE IN THE WESTERN PART OF THE PERI-BALTIC SYNECLISE (NORTHERN POLAND) Summary Caliche deposits were found within the stromatolitic-oncolitic complex of the Zechstein Limestone in northernPoland(Figs. 1–3). They are most commonly developed in the form of pisolites and crusts (Pl. I–IV, Figs. 4–6); the pisolites are hybrids, partly of algal and partly of caliche origin. The probable sequence of events leading to caliche development is presented in Fig. 7. The occurrence of caliche deposits in the Zechstein Limestone of northernPolandhas important palaeogeographical implications as it indicates the periodic subaerial exposure of vast regions of the Zechstein basin during the sedimentation of the Zechstein Limestone.

In the summer of 1991 we installed 27 seismic stations about lake Baikal, Siberia, aimed at obtaining accurately timed digital seismic data to investigate the deep structure and geodynamics of the Baikal rift zone and adjacent regions. Sixty‐six teleseismic events with high signal‐to‐noise ratio were recorded. Travel time and Q analysis of teleseisms characterize an upwarp of the lithosphere‐asthenosphere boundary under Baikal. Theoretical arrival times were calculated by using the International Association of Seismology and Physics of the Earth&#39;s interior 1991 Earth model, and travel time residuals were found by subtracting computed arrival times from observed ones. A three‐dimensional downward projection inversion method is used to invert the P wave velocity structure with constraints from deep seismic sounding data. Our results suggest that (1) the lithosphere‐asthenosphere transition upwarps beneath the rift zone, (2) the upwarp has an asymmetric shape, (3) the velocity cont...

Multi-channel seismic reflection (MCS) experiments were carried out in KR07-09 cruise to investigate crustal structures and deformations in the northern Izu-Ogasawara island arc, by using the R/V KAIREI of Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Swath bathymetry, geomagnetic, and gravity data are also simultaneously observed during this cruise. Five MCS survey lines (Lines IBr5, IBr9, KT01, KT04, and KT05) with 2001.6km of total line length were obtained in this survey. An airgun array with a total capacity of 12,000 cubic inches (eight airguns with 1,500 cubic inches each) was shot with shot spacing of 50 m, air pressure of 2000 psi, and towing depth of 10 m. These airgun signals are recorded by a 204-channel hydrophone streamer cable with group interval of 25 m. The record length and sampling interval were 18 sec (Lines IBr5 and IBr9) or 15sec (Lines KT01, KT04, and KT05) and 4 msec, respectively. The MCS data has sufficient quality to know the crustal deformation of the arc-backarc transition zone. The preliminary interpretations from the onboard processing result indicated unique features of the basement and sediment in the northern Izu-Ogasawara island arc.

This paper summarizes the main results of surveys carried out on the Punta San Matteo serac (Ortles-Cevedale Group, Italy). The monitoring campaigns mainly consisted in surveying the serac with a Total Station (over the period from July 2005 to November 2005) and with a laser scanner. The displacements of the unstable ice mass (about 12 m) and its geometry and volume (about 560,000 m 3) have been calculated. In addition several photographs collected during the field campaigns made it possible to describe the evolution of this unstable ice mass and recorded its partial collapse and gradual breaking into tiny parts. The air temperature trend was also evaluated; the serac displacements resulted not strongly correlated with temperature evolution and the main falling events occurred in the autumn and not in summer when air temperature reached the highest peaks.

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

In this paper we present a correlation between volcanic structures and magnetic anomalies in the Gulf of Naples (Southern Tyrrhenian Sea) based on high resolution magnetic profiling. A densely spaced grid of magnetic profiles coupled with multichannel seismics (seismic source Watergun 15 cubic inch) was recorded in the Gulf of Naples, representing an active volcanic area during the Late Quaternary (volcanic centers of Somma-Vesuvius, Phlegraean Fields and Ischia and Procida islands). The dataset was collected during the oceanographic cruise GMS00-05 which took place during October-November 2000 in the South Tyrrhenian Sea onboard of the R/V Urania (National Research Council, Italy). Shallow volcanic structures in the subsurface of the gulf were recognized by seismo-stratigraphic analysis of high resolution profiles; the volcanic nature of some of these structures was inferred identifying the magnetic anomalies on a high resolution magnetic anomaly map of the gulf. Even if qualitative, the correlations between seismic and magnetic profiles allow us to better assess the geological structure of the Gulf of Naples.

While it is common practice to use sound propagation modelling to estimate the safety shutdown radius around a seismic survey source, only rarely are numerical estimation methods applied to the real-time mitigation of behavioural effects that occur at much greater ranges. For a seismic survey in 2010 near a critically endangered whale population on their feeding grounds, a strategy was implemented for the prediction and field calibration of behavioural safety boundaries that were used for shutdown decisions by shore and vessel based observers equipped with ranging instruments and geo-referencing software. This summary paper describes the steps involved in the estimation, selection and validation of the noise boundaries for different survey lines and under variable propagation conditions. Results of post-event analyses to estimate sound exposure levels and other acoustic parameters of the received seismic pulses along the paths of visually tracked whales are also presented.

Detection, forecasting, early warning, and effective monitoring are key aspects for the delimitation of sinkholeprone areas and for susceptibility assessment and risk mitigation. To attain these goals, direct and indirect techniques can be employed, and the integration of different indirect/non-invasive geophysical methods including 2D-and 3D-electrical resistivity tomography, microgravity, and single-station seismic noise measures was carried out at "Il Piano" (Elba Island-Italy), where at least nine sinkholes occurred between 2008 and 2014. The most likely origin for these sinkholes had been considered related to net erosion of sediment from the alluvium, caused by downward water circulation between the aquifer hosted in the upper layer (Quaternary alluvial deposits) and that in the lower (Triassic brecciated dolomitic limestone and Cretaceous slate). The integrated geophysical survey, therefore, was carried out a) to differentiate shallower from deeper geological layers, b) to detect possible cavities that could evolve into sinkholes, c) to suggest possible triggers, and d) to delimit the sinkhole-prone area. The results of the integrated geophysical surveys suggest that the study area is mainly characterised by paleochannels, and that the sinkhole-prone area boundaries correspond to these paleochannels. superficial drainage of water infiltrating into the soil; and iii) concurrent causes, such as the anthropic effect on the continuity of the superficial drainage network and the extraction of superficial water. Sinkholes can cause spatially dispersed damage. In particular, related losses are direct (e.g., human casualties and damage to property), indirect (e.g., interruption to businesses, transport infrastructure and communication networks) and intangible, especially if they occur in urban areas (Galve et al., 2012; Intrieri et al., 2015; Sevil et al., 2017). Knowing the formation mechanism, some general actions may be identified as countermeasures to mitigate the sinkhole susceptibility of the area and to overcome the environmental and infrastructure problems. In addition, considering that in general, sinkholes are densely clustered in "sinkhole-prone areas" while completely absent in others, key aspects of sinkhole risk mitigation are setting up early warning systems on the basis of effective monitoring programmes (to predict where and when new phenomena will occur) and assessing how

The Western North-Pacific (WNP) gray whale feeding grounds are off the northeastern coast of Sakhalin Island, Russia and is comprised of a nearshore and offshore component that can be distinguished by both depth and location. Spatial movements of gray whales within their foraging grounds were examined based on 13 years of opportunistic vessel and shore-based photo-identification surveys. Site fidelity was assessed by examining annual return and resighting rates. Lagged Identification Rates (LIR) analyses were conducted to estimate the residency and transitional movement patterns within the two components of their feeding grounds. In total 243 individuals were identified from 2002-2014, among these were 94 calves. The annual return rate over the period 2002-2014 was 72%, excluding 35 calves only seen one year. Approximately 20% of the individuals identified from 2002-2010 were seen every year after their initial sighting (including eight individuals that returned for 13 consecutive years). The majority (239) of the WNP whales were observed in the nearshore area while only half (122) were found in the deeper offshore area. Within a foraging season, there was a significantly higher probability of gray whales moving from the nearshore to the offshore area. No mother-calf pairs, calves or yearlings were observed in the offshore area, which was increasingly used by mature animals. The annual return rates, and population growth rates that are primarily a result of calf production with little evidence of immigration, suggest that this population is demographically self-contained and that both the nearshore and offshore Sakhalin feeding grounds are critically important areas for their summer annual foraging activities. The nearshore habitat is also important for mother-calf pairs, younger individuals, and recently weaned calves. Nearshore feeding could also be energetically less costly compared to foraging in the deeper offshore habitat and provide more protection from predators, such as killer whales.

The 3D survey, South Halfway was acquired in December 2019 in Wonowan, BC, Canada. The size of the survey is 94 km 2 and covers a bog and river valley area. Over the bog area, the seismic is limited to 30 Hz and has a higher noise level. The seismic data quality is much improved in the river valley. This caused special challenges for the seismic data processing and pre-stack elastic inversion. We will be discussing these issues and how we solved them in this publication.

The 3D survey, South Halfway was acquired in December 2019 in Wonowan, BC, Canada. The size of the survey is 94 km 2 and covers a bog and river valley area. Over the bog area, the seismic is limited to 30 Hz and has a higher noise level. The seismic data quality is much improved in the river valley. This caused special challenges for the seismic data processing and pre-stack elastic inversion. We will be discussing these issues and how we solved them in this publication.

Theoretical aspects of gamma-ray distribution in rock are described in the article. Information concerning the values of natural gamma radiation of rocks provides for the control of the drilling tool's orientation during horizontal drilling. A simulation of gamma-ray distribution in rock, based upon the example of western Siberian fields, has been made in a COMSOL Multiphysics interactive environment. Test results for a prototype, two-probe device for horizontal borehole positional control are contained in this document. The maximum distance for the registration of changes in the natural gamma radiation of rocks was determined. The attenuation coefficient for the natural gamma radiation of rocks introduced by the influence of a nonmagnetic drill collar was calculated. Practical advice for improvements in the registration characteristics of the prototype device is provided.

Sıgacık Gulf is located south of Izmir (West Anatolia), the third crowded city of Turkey. The gulf is restricted by two important ridges on land from west to east, Karaburun Ridge and Seferihisar Ridge, respectively. Recent geological and geophysical studies suggested that these ridges are dominated by active strike-slip faults both on land and offshore. This manuscript presents the results of the high resolution multi-channel seismic reflection survey which carried out onboard K. Piri Reis, research vessel of Dokuz Eylül University, offshore Karaburun Ridge (Aegean Sea) and surroundings in August-2005. Two main seismic units, lower unit and upper unit, were determined on seismic sections besides the active faults, buried faults and buried folds.

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Effective noise reduction of single-sweep recorded data is achieved by application of a velocity filter process on a decomposed vibrator pattern. This technique promises high resolution results with a minimum effect on signal characteristic. A comparison of the stacked section of records vertically stacked in the field with the stacked section of velocity-filtered receiver gathers shows a significant increase in resolution and signal-to-noise ratio.

Commercial whaling reduced many baleen whale populations to small proportions of their former abundance (Clapham et al. 1999). Protective measures under international law to stop commercial whaling of right whales Eubalaena glacialis and bowhead whales Balaena mysticetus were introduced in 1935, followed by gray whales Eschrichtius robustus in 1946, and humpback Megaptera novae angliae and blue whales Balaenoptera musculus in the mid-1960s (Best 1993). These measures culminated with the moratorium on

A seismic survey conducted in the proximity of the nearshore feeding grounds of gray whales Eschrichtius robustus off northeastern Sakhalin Island, Russia, required the development of a comprehensive monitoring and mitigation plan. Prior to the execution of the seismic survey, the sound levels from the airgun array source were modelled for all seismic acquisition lines. This yielded estimated shoreward boundaries for an assumed disturbance threshold of 156 dB re 1 µPa 2-s sound exposure level (SEL) that allowed an assessment of which lines would require more stringent mitigation. To enable prediction of the sound front under variable propagation conditions, a set of acoustic footprints with a realistic range of parameters was pre-computed. In the field, an acoustic monitoring network of 9 bottom-deployed stations with tethered radio buoys transmitted full waveform data to a shore-based monitoring post. The signals were processed to yield pulse levels for comparison to the model predictions. The appropriate footprint was selected on the basis of the pulse levels received during the initial minute of a seismic line and communicated to observation teams. To further ensure the sustained accuracy of the selected footprint during a line acquisition, the modelled levels were compared in real time to the measured readings as the source moved past the line of monitoring stations; they were consistently found to match the incoming received sound levels within an accepted tolerance of 3 dB. This selection approach resulted in the best available estimation of acoustic exposure even through significant temporal changes in the hydrological conditions.

In this study, we evaluate the relationship between the abundance of seabirds and the different phases of a seismic operation aimed at locating offshore oil fields and taking place in the high seas east of Tierra del Fuego in the southwest Atlantic Ocean. The composition of the bird assemblages and their abundances per species were recorded by means of counts throughout the seismic operation comprising a total of 75 seismic exploration stations between the end of August and the beginning of November 2012. At least 16 species of seabirds were identified, over 60% of which belonged to the Procellariiformes. Seabirds were more abundant during exploration operations in the absence of seismic activity (i.e., compressed air guns were not active). This was also true for two groups of seabirds with contrasting feeding habits (divers and surface divers/scavengers). Our study provides evidence of an avoidance behavior by an assemblage of seabirds to the sounds generated by anthropogenic activities in the Argentine Sea, Southwest Atlantic Ocean. Additionally, our results indicate the need for greater environmental regulation of human activities that introduce low frequency and high intensity sounds in the study area. Resumen • Aves marinas al este de Tierra del Fuego, Argentina durante una evaluación sísmica 3D En este trabajo evaluamos la relación entre la abundancia de aves marinas y las distintas fases de una operación sísmica destinada a la localización de yacimientos petrolíferos en alta mar frente a las costas de Tierra del Fuego, Atlántico Suroccidental. La composición de los ensambles de aves asociadas y sus abundancias por especie se registraron mediante conteos a lo largo de la operatoria sísmica, comprendiendo un total de 75 estaciones de exploración sísmica entre fines de agosto y principios de noviembre de 2012. Fueron identificadas al menos 16 especies de aves marinas, más del 60% de las cuales, fueron Procellariiformes. Las aves marinas resultaron más abundantes durante operaciones de exploración en ausencia de actividad sísmica (i.e., los cañones de aire comprimido no se encontraban activos). Esto también sucedió cuando se consideraron dos grupos de aves marinas con hábitos de alimentación contrastante (buceadores y zambullidores superficiales/ carroñeros). Este estudio proporciona evidencia de un comportamiento de evitación por parte de un ensamble de aves marinas a los sonidos generados por actividades antropogénicas en el Mar Argentino, Atlántico Suroccidental. Nuestros resultados indican la necesidad de una mayor regulación ambiental de las actividades humanas que introducen sonidos de baja frecuencia y alta intensidad en el área de estudio.

A three dimensional (3D) three component (3C) shallow seismic refraction survey was recorded across an extension of the Lake George fault in the butcher's paddock at Bungendore. The ANSIR equipment employed 348 channels in a static spread set out as 4 lines of 29 stations with 3 component geophones. The seismic energy source was a IVI Minivib, T15000. P-& S-wave sweeps were employed. Shear zones are an important concern in most geotechnical investigations. However, they can be especially difficult to separate from artifacts of inversion algorithms, because the traveltime anomalies are relatively small. Saline groundwater in major bedrock fractures, appears to be the source of dryland salinity in the Dubbo area. In other areas of dryland salinity, eg Wagga, the source is wind blown salt. Identifying the source of the salinisation is important in selecting the correct remediation strategy.

The oil industries in the marshlands located in the north of Majnoon oil field south Iraq causes a human and environmental interactions and make great changes in the prevailing ecosystem, accordingly, the development of the field in the marshes areas contradicts (sometimes) with the presence of the population, water bodies, industrial and agricultural facilities. Therefore, a unique special technical methods must be used to reduce the environmental impact when developing the northern part of the field in the marsh environment, such as :

23 shallow marine seismic reflection profiles were collected in Suisun Bay, CA, to help characterize the shallow faults associated with the earthquakes occurred in California during the past 40 years. We analyzed the noises in these shallow marine seismic reflection data, and applied a series of traditional seismic data processing techniques to improve the S/N ratio. Due to the low fold of the reflection data, we constructed analogue single-channel marine reflection profiles, sorted them to CMP domain and stacked the data, which proves to be an effective way in showing shallow structures.

This paper focuses on an evaluation of rotary-percussion drilling (RPD) as a seismic source. Two field experiments were conducted to characterize seismic sources from different rocks with different strengths, i.e. weak shale and hard arkose. Characterization of RPD sources consist of spectral analysis and mean power measurements, along with field measurements of the source radiation patterns. Spectral analysis shows that increase of rock strength increases peak frequency and widens bandwidth, which makes harder rock more viable for seismic-while-drilling purposes. Mean power analysis infers higher magnitude of body waves in RPD than in conventional drillings. Within the horizontal plane, the observed P-wave energy radiation pattern partially confirms the theoretical radiation pattern under a single vertical bit vibration. However a horizontal lobe of energy is observed close to orthogonal to the axial bit vibration. From analysis, this lobe is attributed to lateral bit vibration, which is not documented elsewhere during RPD. Within the horizontal plane, the observed radiation pattern of P-waves is generally consistent with a spherically-symmetric distribution of energy. In addition, polarization analysis is conducted on P-waves recorded at surface geophones for understanding the particle

In January 1983, I returned to OSU to begin formal work on the degree of Doctor of Philosophy. My personal goal was to take a number of courses which I knew from experience would be useful in the burgeoning information age. Luckily for me, since without it I might never have collected and produced enough material to write this dissertation, I became involved with the Oklahoma State University Consortium for Enhancement of Well Log Data via Signal Processing. (We call it the Well Log Project for brevity.) This wonderful group of companies gave us much needed contact with researchers from companies such as Amoco Production Company; Arco Oil and Gas Company; Cities Service Oil and Gas Corporation; Conoco; Dresser-Atlas Company; Exxon Production Research Company; Gearhart Industries, Inc.; Halliburton; International Business Machines; Mobil Research and Development Corporation; Phillips Petroleum Corporation; Seismograph Service Corporation; Sohio Petroleum Company; Texaco Corporation; ...

The accuracy of estimates of cetacean density from line-transect survey data depends in large part on how visible the target species is to the observer. Behavioural data (i.e. surface and dive times) from government- and industry-funded aerial observation programmes (1980–2000) were used to calculate availability correction factors needed to estimate the number of bowhead whales (Balaena mysticetus) from aerial survey sighting data. Correction factors were calculated for bowhead whales exposed and not exposed to seismic operations. Travelling non-calf whales were found to be less likely to be available for detection than other whales, and their availability further declined in the presence of seismic operations. Noncalves were also less available to observers during autumn when exposed to seismic operations than when not exposed, regardless of activity (travelling or otherwise). Such differences in availability appear to reflect behavioural responses to the sound of seismic operatio...

Current work is focussing on further optimisation of the data acquisition, processing and interpretation workflows to ensure fit-for-purpose, long-lived information is delivered to the business. This includes revisiting and reprocessing legacy 3D datasets to harness advances in processing algorithms.

A primary objective of the Statfjord 4-D program is to improve recovery by identifying unswept oil pockets in the Brent reservoirs as targets for infill wells. To assist the mapping of bypassed pay from time-lapse seismic data, a detailed 4-D earth model was constructed over the central portion of the Statfjord Field. The earth model integrates seismic data from a pre-production survey acquired in 1979 and repeat surveys from 1991 and 1997. Log data from 180 wells and flow simulation saturation and pressure predictions, at time steps corresponding to the three survey times, have also been incorporated in the earth model. A Statfjord-specific rock model was applied to link the flow simulator response to acoustic impedance and enable the calculation of timedependent synthetics for comparison with the real seismic amplitude data. The rock model predicts significant increase in impedance when water replaces oil in the Brent sands. Seismic difference analysis with region growing techniqu...

    The depth conversion process is a significant task in seismic interpretation to establish the link between the seismic data in the time domain and the drilled wells in the depth domain. To promote the exploration and development of the Subba oilfield, more accurate depth conversion is required. In this paper, three approaches of depth conversions: Models 1, 2, and 3 are applied from the simplest to the most complex on Nahr Umr Reservoir in Suba oilfield. This is to obtain the best approach, giving less mistakes with the actual depth at well locations and good inter/extrapolation between or away from well controls. The results of these approaches, together with the uncertainty analysis provide a reliable velocity model and more accurate predicted depth that reduced the ambiguity of the subsurface. The uncertainty analysis reveals that Model 3 is considered a more practical and most accurate approach because it gives a minimized standard deviation value of 14 with less residual an...

Surface and deep subsurface geological structural trends, stratigraphic features, and reservoir characteristics play important roles in assessment of hydrocarbon potential. Here, an approach that integrates digital elevation modelling, seismic interpretation, seismic attributes, three-dimensional (3D) geological structural modeling predicated on seismic data interpretation, and petrophysical analysis is presented to visualize and analyze reservoir structural trends and determine residual hydrocarbon potential. The digital elevation model is utilized to provide verifiable predictions of the Dhulian surface structure. Seismic interpretation of synthetic seismograms use twoway time and depth contour models to perform a representative 3D reservoir geological structure evaluation. Based on Petrel structural modeling efficiency, reservoir development indexes, such as the true 3D structural trends, slope, geometry type, depth, and possibility of hydrocarbon prospects, were calculated for the Eocene limestone Chorgali, upper Paleocene limestone Lockhart, early Permian arkosic sandstone Warcha, and Precambrian Salt Range formations. Trace envelope, instantaneous frequency, and average energy attribute analyses were utilized to resolve the spatial predictions of the subsurface structure, formation extrusion, and reflector continuity. We evaluated the average porosity, permeability, net to gross ratio, water saturation, and hydrocarbon saturation of early Eocene limestone and upper Paleocene limestone based on the qualitative interpretation of well log data. In summary, this integrated study validates 3D stratigraphic structural trends and fault networks, facilitates the residual hydrocarbon potential estimates, and reveals that the Dhulian area has a NE to SW (fold axis) thrust-bounded salt cored anticline structure, which substantiates the presence of tectonic compression. The thrust faults have fold axes trending from ENE to WSW, and the petrophysical analysis shows that the mapped reservoir is of good quality and has essential hydrocarbon potential, which can be exploited economically.

To complement a 3D High Resolution streamer survey, Total E&P operated in 2008-2009 a large 3D Ocean Bottom Node (OBN) acquisition to monitor a hydrocarbon reservoir in deep offshore Angola. Mirror node imaging has already proved to be more appropriate for reconciliation with streamer data, but positioning and timing issues as well as azimuthal coherent stacking of data need to be solved to better preserve the high frequency content of data. In this paper we show results obtained with a method for estimating time statics for nodes deployed in a deep offshore environment. Secondly we show that the concept of Offset Vector Binning using hexagonal tiles is applicable to this node data acquisition. Mirrored data migration in Common Offset Vector domain provides Common Imaged Gathers with preserved offset and azimuthal information, which enables a better stacking of information at all offsets and azimuths.