Offshore Boreholes Research Articles

FIRST EVIDENCE OF PALAEO-TETHYAN UPPER TRIASSIC CALCAREOUS NANNOFOSSILS IN NORTH DOBROGEAN OROGEN (ROMANIA)

This study presents the analysis of Upper Triassic sediments from five locations in North Dobrogea(Romania) and the Black Sea. Microfacies analyses on thin sections from the Frecăţei log reveal a shallowing trend and likely an increase in energy upward into the section. The oldest part of the log is characterised by deposition of mudstones transitioning to wackestones, with an increase of bivalves. Similar wackestones are observed in the Izvoarele and Rândunica logs, i.e. microfacies with abundant bivalves, some foraminifera and echinoderms. The offshore boreholes 816 and 817 Lebăda Vest (core CM 9 and CM 31) seem to have been deposited in a basinal or distal marine shelf environment indicated by the presence of mudstones with rare bioclasts. In contrast, sample CM 10 from borehole 816 LV is a micritised grainstone suggesting a deposition in a shallower, higher energy environment.Scanning electron microscope observations reveal a moderate diagenetic alteration in all studied samples, mainly due to dissolution. Two calcareous nannofossil species: Prinsiosphaera triassica triassica and Eoconusphaera zlambachensis were commonly observed in sample F of the Frecăţei log, allowing for assignment of the sediments to the Rhaetian age. Two coccoliths were also observed in sample F of Frecăţei log and sample CM 9 of the borehole 816 LV indicating the presence of coccolithophorids within the study region. This discovery constitutes the first confirmed record of well-preserved, determinable Upper Triassic calcareous nannofossils in the Palaeo-Tethys Ocean.

Tectonics and evolution of the Palmeiras and Xai-Xai Grabens, offshore southern Mozambique

The tectonic evolution of the Mozambique Basin was controlled by the break-up of Gondwana which led to the development of extensional domains along the East African margin. As a result, multiple grabens systems were formed both onshore and offshore southern Mozambique. Two of them are the Palmeiras and Xai-Xai grabens, which are discussed in greater details in this study using an extensive seismic dataset, together with regional gravity and magnetic data. The data show that the Palmeiras Graben evolved from a single extensional phase in the Middle to Late Jurassic (Kimmeridgian?). In contrast, the Xai-Xai Graben records three extensional phases. The first extensional phase occurred in the Late Jurassic (Tithonian?) to Early Cretaceous (Berriasian), the second during the Aptian-Albian and the third in the Late Miocene. The tectonic evolution of these grabens strongly controlled their sedimentary infill during Late Jurassic and Early Cretaceous rifting.Volcanism associated to these tectonic events is documented by onshore and offshore boreholes, as well as by the presence of buried volcanic bodies, lava extruded along fault planes and intrusions of Mesozoic age. Furthermore, a volcano-sedimentary sequence and dome type volcanoes were imaged in seismic data.Differences in tectonic activity impacted the oil and gas potential of both the Palmeiras and Xai-Xai grabens. The sedimentary sequences deposited in the Palmeiras Graben were preserved due to a period of relative tectonic stability predominating from the Aptian to the present day. The burial of the Palmeiras Graben during this period of tectonic stability under a thermal subsidence favoured the generation and preservation of hydrocarbons. In contrast, the Xai-Xai Graben was impacted by intense tectonics, which led to a limited or restricted deposition of strata since the Late Cretaceous to the Paleocene – Early Eocene. As a consequence of a long lasting tectonic activity in the Xai-Xai Graben, uplifting and erosion of potential reservoirs and destruction of existing traps, impacted on the prospectivity for hydrocarbons.

Eocene to present evolution of the Pearl River, China: A quantitative provenance interpretation on large detrital zircon U–Pb geochronological data

AbstractDrainage evolution of the Pearl River, one of the major rivers in the eastern margin of the Asian continent, has important implications for the tectonomorphic evolution of the northern margin of the South China Sea and the southeastern Tibetan Plateau. Previous reconstructions using different methods suggested discrepant timings for the formation of river, ranging from Early Oligocene to Middle Miocene. Here, we address this heavily debated topic using quantitative unmixing modelling of detrital zircon data from the Pearl River Mouth Basin in the northern margin of the South China Sea. In this study, we develop a novel approach for estimating the relative contributions of detrital zircon sources to their shared sink, and propose to use the correlation coefficients among zircon contribution models to evaluate the trade‐off among sources with similar age spectra, to avoid the potential overinterpretation of individual contributions. Our new method is applied to new (997) and published detrital zircon U–Pb data from offshore boreholes and modern Pearl River samples to quantitatively interpret and reconstruct the sediment provenance of the Pearl River Mouth Basin and the development of the Pearl River. Our findings reveal that the provenance change of the Pearl River Mouth Basin can be divided into three main stages. Eocene sediments were mainly sourced in the intra‐basinal highlands and the eastern coastal tributaries, indicating a local drainage system. Early Oligocene provenances extended westward, as shown by the increase in sediment contribution from the central and western parts of the Pearl River (28% in total). Since the Late Oligocene, the eastern, central and western parts of the modern Pearl River have contributed equal amounts of zircons to the Pearl River Mouth Basin, indicating the establishment and long‐term stability of the modern‐like drainage system, as highlighted by our new data acquired from the borehole Miocene strata. The Late Oligocene westward expansion of the Pearl River is consistent with the timing of the coeval breakup and spreading of the South China Sea and the intensified Asian monsoon precipitation, highlighting the importance of base level fall and climate in controlling the drainage evolution.

Long‐Term Offshore Borehole Fluid‐Pressure Monitoring at the Northern Cascadia Subduction Zone and Inferences Regarding the State of Megathrust Locking

AbstractThe Cascadia subduction megathrust off the Pacific Northwest follows an “end member” seismogenic behavior, producing large (up to moment magnitude 9) but infrequent (every several hundred years) earthquakes and tsunamis. Crustal deformation associated with the ongoing plate convergence has been characterized by land‐based geodetic observations, but the state of locking across the full breadth of the seismogenic fault is poorly constrained. We report results of offshore monitoring of borehole fluid pressure, as a proxy for formation volumetric strain, at a site ∼20 km landward of the Cascadia subduction deformation front since 2010. The multi‐depth pressure records were plagued by hydrologic noise, but noise at the deepest monitoring level (303 m sub‐seafloor) abated in 2015. Subsequently, including at the times of regional large earthquakes that caused significant dynamic stressing, no persistent pressure transients are present above a threshold of 0.08 kPa imposed by unremovable oceanographic signals, corresponding to a strain detection limit of ∼16 nanostrain. Simple dislocation models using local megathrust geometry suggest a resolvable slip of <1 cm along a trench‐normal corridor beneath the borehole for a range of slip‐patch dimensions. A large slip patch can be well resolved even at considerable along‐strike distances from the borehole; for instance, ∼10 cm slip is detectable over a 200‐km strike range for a slip‐patch radius of ∼50 km. This high sensitivity for detecting slip, along with the lack of observed events, stands in stark contrast to observations at other subduction zones, and suggests that the Northern Cascadia megathrust is most likely fully locked.

Some geotechnical soil properties of western bank of Khor Al-Zubair channel coast at Khor Al-Zubair Port location, southern Basrah, Iraq

Five Offshore Boreholes have been drilled by the National Construction Center at Basrah with cooperation the Marine Science Center/Basrah University, together with three Onshore Boreholes at the western bank of Khor Al-Zubair channel during July 2009. The drilling machine of Auger type has been used for drilling. Representative soil samples were taken at appropriate intervals ranged between 0.5 and 2.0 meters depth or where the stratum has been changed. Onshore boring depths ranged from 19.0 – 20.5 m, from natural ground surface, while, the offshore borings were from 7-16 m from the bed level. The depths of drilling reached the bedrock which is hard enough to require N-value of more than 50 blows. Standard Penetration Test (SPT) has been carried out for each 2m depths. Grain size analysis, moisture content, Atterberg limits of these soils were also determined. The results show that there are two main strata making up the coast bank of the navigational channel of Khor Al-Zubair. First is Marly silty Clay or fat clay soil which has of a thickness18 m, and gradually changes from very soft- m.stiff to stiff-v.stiff which belongs to the Hammar deposits. The second is Silty Sand layer which has two types of sandy soil, these are: (1) borrowed Back filled layer as surficial compaction soil with of a thickness 2.0 m, and (2) are interacted lenses stratum between the gray stiff silty clay and the hard brown silty clay in the near and onshore Boreholes which belongs to the Dibdiba formation.
 

New insights on source rock maturation in the southern Gulf of Gabes (Tunisia) via 1-D modeling: effect of combined corrected borehole temperature and thermal conductivity on heat flow distribution

Effective quantitative modeling of petroleum generation processes requires a reasonable knowledge of various factors controlling the transformation of organic matter into oil or gas. Nevertheless, it is widely accepted that thermal conductivity and temperature have the dominant roles in controlling generation. In Tunisia, previous source rocks burial and maturity modeling were mostly carried out using corrected borehole temperature after applying formula which were set to fit domains other than Tunisian basins. The main purpose of this work is to propose a suitable method of temperature correction to fit the studied area but more importantly to emphasize the impact of thermal conductivity on heat flow distribution. For that, a total of 222 temperature values including 170 bottom hole temperatures (BHT) and 52 drill stem tests (DST) were collected from 30 onshore and offshore boreholes. The proposed equation generates corrected temperature close to true formation temperatures. As thermal conductivity depends on the relationships between a sedimentary interval component, two equations were used to determine the conductivity of each unit which are the harmonic and the geometric means. To assess the importance of applied corrections, three scenarios were tested for an Albian source rock using the 1-D Basin-Mod software. The combination of corrected BHTs and thermal conductivity provide higher source rock maturation than when uncorrected data are used. Amounts of generated hydrocarbons are estimated to become two times higher. This would guide for complementary reserves estimations to be applied in the region for better calculation accuracy.

Directional Hydraulic Characteristics of Reservoir Rocks for CO2 Geological Storage in the Pohang Basin, Southeast Korea

This study conducted core sampling of an offshore borehole for geological reservoir characterization of a potential CO2 storage site in southeast Korea. From this, two promising geological formations at ~739 and ~779 m were identified as prospective CO2 storage reservoirs. Injection efficiency and CO2 migration were evaluated based on directional measurements of permeabilities from core plugs. The directional transport properties were determined using both a portable probe permeameter and a pressure cell capable of applying different in situ confining pressures. Both steady state and unsteady state measurements were used to determine permeability—the method selected according to the expected permeability range of the specific sample. This expected range was based on rapid screening measurements acquired using a portable probe permeameter (PPP). Anticipated performance of the prototypical CO2 injection site was evaluated based on flow modeling of the CO2 plume migration pathway including CO2 transport through the overlying formations based on the measured directional hydraulic properties. These analyses revealed that the injection efficiency at a depth of 739 m was double that at 779 m. These correlations among and distributions of the directional permeabilities of the potential CO2 geological storage site can be utilized for the assessment of CO2 storage capacity, injectivity, and leakage risk.

Structural reconstructions of the Eastern Barents Sea at Meso-Tertiary evolution and influence on petroleum potential

Barents Sea basin is the most explored and studied by the regional and petroleum geologists on the Russian Arctic shelf and has approved gas reserves. However, there are many questions in the petroleum exploration, one of them is the structural reconstruction. During its geological evolution, Barents Sea shelf was influenced by the Pre-Novaya Zemlya structural zone that uplifted several times in Mesozoic and Cenozoic. The main goal of the research is to clarify the periods of structural reconstructions of the Eastern Barents shelf and its influence on the petroleum systems of the Barents Sea shelf. A database of regional seismic profiles and offshore borehole data collected over the past decade on the Petroleum Geology Department of the Lomonosov Moscow State University allows to define main unconformities and seismic sequences, to reconstruct the periods of subsidence and uplifts in Mesozoic and Cenozoic. The structural reconstructions on the Eastern Barents Sea in the Triassic-Jurassic boundary led to intensive uplifts and formation of the huge inversion swells, which is expressed in erosional truncation and stratigraphic unconformity in the Upper Triassic and Lower Jurassic strata. In the Jurassic period, tectonic subsidence reigned on the shelf, when the uplifts including the highs of Novaya Zemlya were partially flooded and regional clay seal and source rocks – Upper Jurassic «black clays» – deposited on the shelf. The next contraction phase manifested itself as a second impulse of the growth of inversion swells in the Late Jurassic-Early Cretaceous. Cenozoic uplift of the Pre-Novaya Zemlya structural zone and the entire Barents Sea shelf led to significant erosion of the Mesozoic sediments, on the one hand, forming modern structural traps, and on the other, significantly destroying the Albian, once regional seal.

The Advanced Prototype of the Geohydroacoustic Ice Buoy.

The new-generation geohydroacoustic buoy prototype is designed for simultaneous acquisition of acoustic, hydroacoustic, and seismoacoustic data in various environmental conditions, including onshore and offshore boreholes, yet is specifically targeted for operation in Arctic seas as an element of the distributed ice-class drifting antennas. Modular structure of the geohydroacoustic ice buoy incorporates the advanced data logger and a combination of sensors: vector–scalar hydroacoustic (0.01–2.5 kHz) accelerometer, broadband molecular–electronic (0.03–50 Hz) velocimeter, as well as optional hydrophones. The distinguishing feature of the geohydroacoustic buoy is its low power consumption responsible for consistent autonomous operation of the entire measurement system for at least one week. Results of continuous laboratory tests carried out at the geophysical observatory of the Geophysical Survey of the Russian Academy of Sciences (GS RAS) in Obninsk are presented. It has been confirmed via comparative analysis of recorded time series featuring microseismic noise and teleseismic earthquakes that the prototype well meets the high standards of modern seismology.

Near‐shore geophysical and geotechnical investigations in support of the Trieste Marine Terminal extension

ABSTRACTThe Port of Trieste is an international hub for land and sea trade with the dynamic markets of central and eastern Europe. Thanks to its deep natural draft (about 18 m), the modern high‐capacity vessels can moor to the piers. In view of the foreseen increase in maritime traffic, this harbour is undergoing modernization in order to improve the commercial traffic capability. In this expansion plan, the container Trieste Marine Terminal, Pier VII, is seeking an extension by about 200 m. In support of this feasibility study, multidisciplinary data acquisition was conducted in order to characterize the seabed, the sub‐bottom sediments and the bedrock (flysch formation) in front of the Trieste Marine Terminal. The acquisition of high‐resolution swath bathymetry, side‐scan sonar and magnetometer data allowed a detailed analysis of the seabed conditions from an environmental and safety perspective. High‐resolution seismic reflection data enabled us to characterize the Plio‐Quaternary soft sediments and the underlying bedrock. A static underwater refraction survey was performed using hydrophone array deployed on the sea bottom to obtain seismic velocities and to achieve a reliable time‐to‐depth conversion of reflection seismic data by first‐arrival tomographic inversion. In addition to geophysical investigations, 11 offshore boreholes were drilled for detailed logging. In situ standard penetration tests were performed on core samples with the use of a pocket penetrometer and pocket vane in order to obtain uniaxial compressive strength, undrained shear strength and undrained cohesion values, and assess the cohesive soils. During drilling, 17 undisturbed samples and 12 semi‐disturbed samples were extracted to perform laboratory tests for the identification of the principal geotechnical parameters. The goal was to obtain a reliable geological/geotechnical model in front of the Trieste Marine Terminal – from the seabed to the bedrock. Below the seafloor, a sequence of about 20–30 m thickness, containing Plio‐Quaternary soft sediments, overlies the flysch, which locally presents alteration with rocks of reduced quality. The geophysical–geotechnical integrated approach allowed us to identify and map the top of the bedrock and provided valuable information for planning the pier extension project.

Gamma-ray log correlation and interpretation of Fitton’s and Casey’s stratigraphy with offshore borehole 99/16-1

The Chale Bay type section of the Lower Greensand Group (LGS) Atherfield Clay, Ferruginous Sands and Sandrock formations is characterised by members, bounded by hiatuses, formerly recognised (if not named as such) by Fitton as his ‘groups’ and Casey in defining ammonite zone and sub-zone boundaries. Subsequent work has shown that some of the formations of the LGS are recognised elsewhere on the Isle of Wight, in southern England and in northern France. Likewise, some members of the Atherfield Clay and Ferruginous Sands formations can be recognised beyond the Chale Bay type section. In this work, we have measured outcrop gamma-ray emission from the type section: gamma-ray peaks recognised on all datasets are used to attempt a correlation of the Lower Greensand Group between the Isle of Wight and an offshore borehole (99/16-1). This is partially successful, showing that Fitton and Casey’s stratigraphy maybe recognised basin-wide.

Groundwater salinity patterns along the coast of the Western Netherlands and the application of cone penetration tests

Submarine groundwater discharge is an important part of the hydrological cycle, but remains under-investigated for confined aquifers with no surface outcrop at the beach. This paper considers the offshore directed flow of fresh groundwater in the unconfined and confined aquifers along the coast of the Western Netherlands. Salinity patterns based on hydrological, geological, and geophysical field data are presented in five shore-normal hydrogeological cross-sections, extending from the beach to 4km inland. The offshore continuation of the fresh groundwater is discussed using analytical models and cone penetration tests (CPTs) performed at the beach. All CPTs taken around the low water line of the intertidal zone reveal that changes from saline to fresh groundwater are always associated with a low-permeable layer. Such a low-permeable layer, which can be as thin as a few decimetres, may form the confining layer between the unconfined and confined aquifers, or can occur within of the unconfined aquifer. Due to its high vertical resolution, a CPT is an effective method to detect these variations in salinity and lithology. At each of the investigated locations, freshwater was present in the confined aquifer. Assuming that this fresh groundwater is part of an active flow system, the submarine freshwater tongue is estimated to extend at least a few hundred meters offshore, based on analytical model calculations. Hydrochemical data from an old offshore borehole, however, suggest this may be an underestimate and that the submarine freshwater tongue originates from former times when the coastline was located further westward than nowadays.

Delineation of tunnel valleys across the North Sea coastline, Denmark based on reflection seismic data, boreholes, TEM and Schlumberger soundings

Buried tunnel valleys are elongated depressions eroded into the substratum during the Pleistocene glaciations. Nine such valleys are mapped on- and offshore in a 300 km2 area located at the Danish North Sea coast. The delineation of the buried valleys is based on an extensive data set consisting of on- and offshore 2D seismic data, TEM (Transient Electro-Magnetic) soundings, Schlumberger soundings, and boreholes. The valleys are observed as discrete incisions with three overall orientations: SSE–NNW, ESE–WNW, and SSW–NNE. They have depths between 75 and 185 m, widths up to 1.8 km, and lengths from 7 to 25 km. The infill comprises till, glaciofluvial sand, and glaciolacustrine clay and silt. Younger tunnel valleys are found to often re-use pre-established valleys generating cut-and-fill structures which are clearly revealed on the reflection seismic profiles. Cross-cutting relations, preferred orientations, and morphology support that three of the tunnel valleys cross the North Sea coastline. It is suggested that the nine valleys were formed during at least six events that occurred through one or more pre-Weichselian glaciations.

Proveniência dos arenitos da Bacia de Campos (Andar Alagoas) por meio da composição da granada

Neste trabalho, realizou-se um estudo da composição química da granada para a identificação das principais rochas-fonte envolvidas na proveniência dos arenitos da Bacia de Campos, Andar Alagoas. Em análises obtidas por microssonda eletrônica, dos 17 poços do segmento offshore do estudo, verificou-se a contribuição de diferentes rochas-fonte portadoras de granadas, identificadas como dos tipos A, B e C. Entre elas, predominaram as granadas do tipo B. Um refinamento dessa classificação permitiu categorizar tais granadas em granadas do tipo Bi, derivadas de rochas ígneas ácidas e intermediárias, notadamente granitoides. A ausência ou pequena incidência de zonações composicionais e de inclusões, embora não excluam totalmente as outras categorias, apontam para essa classificação. Granadas do tipo D e E não aparecem em nenhuma das amostras analisadas. A interpretação dos resultados de aproximadamente 4.000 análises das 65 amostras indicou duas contribuições principais para a proveniência desses arenitos: no setor sul da bacia, material derivado do terreno Cabo Frio (rochas metamórficas da fácies anfibolito superior a granulitos, granitos, metapelitos aluminosos e secundariamente metabasitos) e, na porção norte da bacia, derivação do terreno oriental do Orógeno Ribeira (terreno de alto grau e granitoides associados). A direção de suplemento sedimentar mais importante é de sudoeste para nordeste, interpretada como resultado da identificação dessa maior contribuição do terreno-fonte. Os arenitos localizados no setor norte, com granadas derivadas do tipo B e Bi, sobretudo, indicam a presença dominante de rochas granitoides na área-fonte. Essas rochas-fonte geram areias de composição mais quartzosas e/ou quartzo-feldspáticas, com maior potencial para produzirem arenitos-reservatórios de melhor qualidade.

Perfiles de concentración del cloruro reconstruidos debajo del lecho marino en Hong Kong (China) y sus implicancias en los recursos de agua subterránea mar adentro

Offshore hydrogeology has been much less studied compared to onshore hydrogeology. The marine Quaternary system in Hong Kong (China) consists of interlayers of aquitards and aquifers and was part of the Pearl River Delta when the sea level was low before the Holocene. Core samples from six offshore boreholes were collected to measure the chloride concentration in the system by adding deionized water. A method was proposed to convert the sediment chloride into that of the original pore water. A one-dimensional sedimentation-transport model was developed to simulate the historical conservative transport of the reconstructed pore-water chloride. The model integrates present knowledge of stratigraphy and the historical evolution of the geological system. The chloride concentration profiles show that the chloride decreases from an average of 13,800 mg/L in the first marine unit to an average of 5,620 mg/L in the first aquifer. At the bottom of one borehole, the concentration is only 1,420 mg/L. The numerical model shows that the vertical chloride distribution is due to diffusion-controlled downward migration of seawater. The second marine unit obstructs the downward migration, indicating its low permeability and good aquitard integrity. The relatively fresh or brackish water in deep aquifers protected by the aquitard has the potential to be used as drinking water following some treatment, or at least as raw water with much cheaper desalinization compared with using seawater. The methodology and findings in this study are instructional for other coastal areas with similar geology and history in the South China Sea.

Fluvial system development and subsequent marine transgression in Yellow River (Huanghe) delta and its adjacent sea regions during last glacial maximum to early Holocene

Paleotopography of the Yellow River (Huanghe) delta area and the western Bohai Sea during the last glacial maximum (LGM) is important to understand fluvial activities of the Yellow River linked with the LGM climate. By integrating data sets of both onshore and offshore borehole cores and offshore high-resolution seismic profiles, we reconstructed the paleotopography of this area from the LGM to the early Holocene. The fluvial sediment facies of the LGM identified in these cores was characterized by poorly sorted medium- to coarse-grained sands, which shows chaotic patterns in seismic profiles. REE characteristics and clay mineral components of the fluvial sediments suggest that they were derived mostly from the paleo-Yellow River. The basal and top bounding surfaces of the fluvial sediments slope very gently toward the northeast, similar to the present morphology of the North China Plain formed by the Yellow River. No incised valley morphology is detected in the basal topography, because of the long distance from the study area to the paleoshoreline during the LGM, and also because of the very gentle gradient of the paleo-Yellow River from the northern part of North China Plain to the continental shelf area, with concave-upward morphology. Aggradational stacking of the fluvial sediments over the entire North China Plain and in the study area indicates that the Yellow River flowed in these areas during the LGM to the early Holocene. The Holocene marine and coastal sediments onlap onto the underlying fluvial sediments. These basal marine or brackish sediments are diachronous from offshore areas of the Bohai Sea to the Yellow River delta area, with older sediments in the east and younger sediments in the west, which clearly reflects the early Holocene marine transgression from the North Yellow Sea to the Bohai Sea.

Advanced Borehole Seismic Acquisition challenges and Successes in Large LNG Project

In this paper we will describe the operational success of largest offshore borehole seismic job which paved the way for several advance borehole seismic projects in Gorgon, Wheat-stone and other projects. The primary objective of the survey was to obtain true vertical time-depth relation and high resolution 2D image below and around the well path for better understanding of reservoir while secondary objective was anisotropy parameters estimation to improve the reprocessing of surface seismic. The followings were the main challenges to this project: Finding a suitable boat/crane for deployment of sources at safe distance from boat hull. Acquisition sequence was switching between different surveys i.e Walkabove and Walka-ways, which made acquisition quite complex. Finding a properly trained navigator for the job. Minimizing rig time Noise attenuation The followings are main conclusions and recommendations VSP modelling was essential for survey design Survey lines were optimized to minimize the rig time Good prejob planning is a key of operation success Poor coupling noise have successfully attenuated during processing Successful acquisition of a comprehensive Walkabove & Walkaways data sets. Combined Walkabove and Walkaway VSPs and Surface Seismic helped to better under-stand the reservoirs. Integration of different data sets multiply the value of each of the elements. Reliable time, depth and velocity information was achieved from Walkabove data set. Recommendations for future acquisition work based on lesson learned on first well.

Scientific Drilling

Abstract. The Motion Decoupled Hydraulic Delivery System (MDHDS) is a new downhole tool delivery system that is deployed by wireline and uses drillstring pressure to advance a penetrometer (or other downhole tool) into the formation at the bottom of offshore boreholes. After hydraulic deployment of the penetrometer, it is completely decoupled from the BHA; this eliminates the adverse effects of ship heave. We tested the MDHDS at Site U1402 (the location of Site 1073, ODP Leg 174A), offshore New Jersey, during two days of ship time during Integrated Ocean Drilling Program (IODP) Expedition 342. In one deployment we emplaced a penetrometer successfully and documented that it was decoupled from drillstring movement. Based on this successful field test, the MDHDS has been certified by the U.S. Implementing Organization (USIO) for shipboard use. The MDHDS will replace the previous deployment system, the Colletted Delivery System. The MDHDS is an IODP-funded engineering development led by The University of Texas at Austin, in conjunction with the USIO and Stress Engineering Services. This sea trial was the culmination of a seven-year development effort that included extensive engineering design and fabrication. doi: 10.2204/iodp.sd.15.07.2013

Applications of engineering seismology in urban areas

I present two case studies which describe applications of engineering seismology in urban areas: High-resolution shallow offshore 3D seismic survey for the Bosphorus Subsea Road Tunnel Project, and seismic, geotechnical, and earthquake engineering site characterization for a residential project in Istanbul. In Case study 1, I conducted a 3D high-resolution shallow seismic survey in 2011 to confirm the geometry of the future Bosphorus Subsea Road Tunnel traverse. I processed the data to obtain 3D PSTM and PSDM volumes, and interpreted these image volumes and correlated the interpretation results with the offshore borehole data. With the recoverable signal band of 30–960 Hz, I attained a vertical resolution of less than 1 m.

The Motion Decoupled Delivery System: A New Deployment System for Downhole Tools is Tested at the New Jersey Margin

The Motion Decoupled Hydraulic Delivery System (MDHDS) is a new downhole tool delivery system that is deployed by wireline and uses drillstring pressure to advance a penetrometer (or other downhole tool) into the formation at the bottom of offshore boreholes. After hydraulic deployment of the penetrometer, it is completely decoupled from the BHA; this eliminates the adverse effects of ship heave. We tested the MDHDS at Site U1402 (the location of Site 1073, ODP Leg 174A), offshore New Jersey, during two days of ship time during Integrated Ocean Drilling Program (IODP) Expedition 342. In one deployment we emplaced a penetrometer successfully and documented that it was decoupled from drillstring movement. Based on this successful field test, the MDHDS has been certified by the U.S. Implementing Organization (USIO) for shipboard use. The MDHDS will replace the previous deployment system, the Colletted Delivery System. The MDHDS is an IODP-funded engineering development led by The University of Texas at Austin, in conjunction with the USIO and Stress Engineering Services. This sea trial was the culmination of a seven-year development effort that included extensive engineering design and fabrication. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.15.07.2013" target="_blank">10.2204/iodp.sd.15.07.2013</a>