Properties of Celtic Sea Chalk

The aim of this study is to compare water depths measured by manually and PLC from a Class A Pan in field conditions using ultrasonic transducer. The study was conducted in garden of Faculty of Agriculture, University of Kahramanmaras Sutcu Imam in the summer season of 2019. A steel meter was used to measure water depth manually in the evaporation pan. Using the ultrasonic transducer, PLC measured water depth from the evaporation pan between 140 and 223 mm water depth at 8:00 am. An ultrasonic transducer is attached one end of sliding buttress, at which was 50 cm above from its inner-bottom at the center of the evaporation pan. The ultrasonic transducer was set to be able to read water depth and calibrated using sliding buttress. A program was written in CODESYS-ST language to measure the water depth from a Class A Pan using PLC, which was connected the ultrasonic transducer and uploaded to PLC. With the program, digital water depths were converted to millimeter water depths. To be able to read the water depth more accurately, each depth value read by the PLC was determined by averaging 30 measurements made successively at 300 millisecond intervals. In this processes, moving average method was used. Water depth measured by PLC was saved on the SD (secure digital memory) card. In the manual water depth measurements, there were 26 observations. The water depths on the manual measurement dates were matched with the water depths measured by PLC. A regression analysis was performed between the water depths measured by the steel meter and PLC in the pan, and determination coefficient (R2) was result as 0.96. The Mean Absolute Percent Error (MAPE) of these two data sets was calculated as 2.3%. The level of agreement between the two data sets; if the MAPE is below 10%, it is considered “very good”. The results of this study revealed that the PLC could measure the water depth close to the measured manually water depth in the evaporation pan with an ultrasonic transducer.

Water content may have a crucial effect on the petrophysical and mechanical properties of high porosity rocks such as chalk. Consequently, the water fluctuations may significantly influence the behaviour of engineering structures that are constructed in chalks. It is the aim of this study to illustrate how the elastic and strength properties of chalk can evolve considering water content variation using P-wave velocity and analytical analyses. To study the influence of water on the ultrasonic compressional wave velocity (VP), measurements of travel time of three samples subjected to different water content were performed. The Uniaxial Compressive Strength (UCS) in dry and saturated chalk specimens was also estimated. To clarify the possible influence of lithology on the physicomechanical properties of rocks, three samples of phosphatic chalk were studied in thin sections. Automated mineral analysis and textural imaging of the samples were performed using an FEI QEMSCAN®. The analyses of the Ultrasonic tests reveal that changes in the water content are associated with variations in the P-wave velocity. Based on P-wave velocity changes as a function of water content, analytical models have been used to predict the elastic and strength properties. The data indicate that the presence of water significantly reduced the elastic and strength parameters of the chalk, a result that is in agreement with the UCS laboratory tests. The derived equations can be used for predicting the elastic and strength properties of high-porous chalk from the P-wave velocity as a function of water content. This approach may avoid the necessity for time-consuming laboratory testing.

Control of modern dinoflagellate cyst distribution in the Irish and Celtic seas by seasonal stratification dynamics

ABSTRACTPrevious studies using commercial airborne electromagnetic equipment that is not optimized for marine surveying have demonstrated the use of airborne electromagnetic methods for measuring water depth and estimating sediment thickness. A new prototype helicopter time‐domain airborne electromagnetic system, SeaTEM(0), is now under development for bathymetric surveying. The first sea trial of the SeaTEM(0) system took place over Broken Bay, New South Wales, Australia, in shallow water up to ∼30 m in depth. Broken Bay was chosen because the separate paleodrainage systems for the Hawkesbury River, Brisbane Water and Pittwater, which join in Broken Bay give rise to paleovalleys infilled with unconsolidated sediments, ranging in thickness between 0 m (bedrock outcrop) and ∼200 m. The survey area also included a tombolo with a beach either side, which provided the opportunity to measure water depth through a surf zone. Sediment thickness and water depth is predicted from stitched layered‐earth inversion of data based on a simplified two‐layer model that represents seawater and sediment overlying a resistive half‐space basement (bedrock). The resulting bathymetric profiles show agreement typically to within ∼±1 m and ∼±0.5 m with known water depths in areas less than 20 and 6 m deep respectively. The inverted depth profile of the second (sediment) layer is noisy; however, the profiles reveal coarse topographic features of paleovalleys to depth limits of ∼60 to 80 m below sea level in 20 to 30 m water depth, as well as resolving bedrock ridges and exposed reefs in shallow waters.

Accumulated oil production from the Troll field offshore Norway will reach one billion barrels of oil in the spring of 2005. At 315-340 meters water depth, Troll is an oil and gas field with approximately 1,700 billions Sm3 of gas and four billion barrels of oil in place. Troll consists of two main structures, Troll East and Troll West, the latter divided into an oil and gas province. The oil is located primarily in Troll West in thin oil layers of 4-27 m. This article describes how the Troll West field has been developed from a gas field with no commercial oil to a gas and oil field with accumulated production surpassing one billion barrels of oil during the spring 2005. Introduction This article describes the multi-disciplinary success story of the Troll West oil and gas field. Originally, the Troll field's thin oil layer of 4-27 m thickness was considered to have no commercial value. The development of horizontal drilling technology combined with early testing and oil production from a floating platform (FPSO) led to the conclusion that Troll West oil could be commercially produced. The most productive part of the field is the Troll West Oil Province (TWOP) with 22–27 m oil thickness. It was first developed by the installation of five subsea clusters and the Troll B FPSO in 1995. Drilling and production performance led to further development of the even thinner oil layers (4–14 m) in the Troll West Gas Province (TWGP), and installation of the separate Troll C platform, which began producing in 1999. The Troll field is one of the largest subsea developments in the world with 107 wells currently in operation. Increased oil recovery from the thin oil layers in Troll West has been possible by gradually increasing the length of the horizontal sections and introducing multi-lateral wells to reduce cost and increase the sweep area. Advanced drilling and completion technology have been developed and implemented. Seismic and geological methods determine the location of the high-permeable sands with high accuracy. The drilling and completion operations have been significantly more efficient, resulting in a higher drainage area per invested capital. Continous production drilling with up to four floating drilling rigs has been carried out since production start in 1995. More than 30 multi-branched wells with zonal control are in operation. Five three-branched, two four-branched and one five-branched well are currently in production. Figure 1. The Troll Field is located some 80 kms west of Bergen, Norway. (available in full paper) The Troll Field The Troll field is located some 80 kilometers west of Bergen, off the coast of western Norway. The water depth is 315-340 m. The Troll field consists of Troll East, mainly covered by production license 085, and Troll West, mainly covered by production license 054, see Fig. 1. The Troll license partners are:ConocoPhillips Norge 1.62374 %Total E&P Norge AS 3.69096 %A/S Norske Shell 8.10145 %Norsk Hydro Produksjon AS 9.77914 %Statoil ASA 20.80471 %Petoro AS (Norwegian state) 56.00000 %

Introduction The Na Kika project is among the most complex subsea developments executed by our industry and faced a number of unique flow assurance challenges due to the extreme water depth (5800 to 7600 ft), distributed well layout, variability in produced fluids (from six distinct fields), offsets of up to 26 miles and relatively low temperature reserves. Flow assurance strategies thus were a key driver to system selection and overall assessment of project profitability. This paper gives an overview of the development of the fully integrated dynamic simulator that incorporated flow assurance and other novel processes into a unique training strategy for successful operation of the Na Kika host and subsea systems. Background The Na Kika project consists of six oil and gas fields in the Mississippi Canyon area of the Gulf of Mexico that are tied back to a semi submersible based floating production facility in 6350 ft of water. Water depths range from 5800 to 7600 ft. The individual fields in the Na Kika base development are Ariel, Kepler, Fourier, Herschel, and East Anstey, each of which will be developed as subsea fields with produced fluids routed back to a floating host roughly located in the center of the development area. See Figure 1. The sixth field, Coulomb, will be produced by a single flowline back to the Na Kika processing facility. Offset distances from the host are in the range of 5 (Ariel) to 26 miles (Coulomb). The Na Kika subsea layout consists of a single, 10" × 16" pipe-in-pipe flowline loop for those fields north of the host (Ariel and Kepler). On the south side, there are two flowline loops, an 8"x12" pipe-in-pipe insulated oil loop for the Herschel and selected Fourier wells, and an 8" un-insulated gas loop for the East Anstey and selected Fourier wells. The subsea system at Fourier includes the flexibility to allow wells to produce back through either the gas or the oil flowlines, particularly with jumper reconfiguration. Production from the Coulomb wells, which lie south of the host, will be transported by a single 26-mile flowline back to the host. This subsea architecture deviates significantly from earlier projects through the use of flowline loops, as opposed to dual lines to a manifold, and the use of a single flowline for the Coulomb gas wells. Hydrate Control and Remediation Strategy All deepwater subsea projects have hydrate concerns due to the fact that hydrocarbon systems fall into the hydrate stability regime at the typical seabed temperature of 39 ºF when pressures exceed 400 to 600 psig. Hydrate control and remediation is a particular concern for Na Kika due to the extreme water depth at the location, which leads to high hydrostatic head, and the downward slope of the flowlines on the north side of the host. The single flowline tieback for the Coulomb gas wells introduces additional hydrate risks and concerns, including the effectiveness and safety of single sided blowdown for hydrate remediation.

The results of three decades of seafloor research provide the most reliable information on the importance of water depth in massive sulfide formation. Available data from over 130 occurrences show that water depths of seafloor vent sites vary with plate tectonic setting and the regional magmatic and volcanic environment. The shallowest hydrothermal systems in subduction-related settings are hosted by arc volcanoes. These shallow vent sites have a number of features in common with subaerial epithermal systems. Massive sulfide occurrences in arc-related rifts, the most likely setting for many ancient analogs, are generally restricted to water depths from ~700 to 2,000 m, with rifts developing within old arc crust at the deeper end of this range. Back-arc spreading centers proximal to arcs host massive sulfide deposits at depths of ~1,500 to 2,000 m. The deepest hydrothermal systems occur along mature back-arc spreading centers distal to volcanic arcs where water depths range from ~2,000 to 3,700 m. These deeper vent sites probably represent the best modern analogues of ophiolite-hosted massive sulfide deposits. Boiling of the hydrothermal fluids is common at volcanic arcs and in arc-related rifts. In these environments, elevated magmatic gas contents of the hydrothermal fluids can contribute to the widespread occurrence of phase separation and associated gas loss. By contrast, the high ambient pressures in deep marine hydrothermal systems along mature back-arc spreading centers prevent fluids from boiling during their ascent to the seafloor. Boiling controls the maximum temperature at which hydrothermal fluids discharge at the seafloor and, therefore, influences the metal content of seafloor sulfide deposits. Copper-rich massive sulfides typically occur at water depths exceeding ~1,000 m, whereas Zn- and Pb-rich occurrences may form at any water depth. Boiling can be an important control on Ag and Au grades but is not the only factor controlling precious metal enrichment in massive sulfides. Shallow marine hot spring deposits can be highly enriched in trace metals such as As, Hg, and Sb. Submarine volcanic arc and back-arc settings are geologically complex and significant variations in water depth can occur over short distances. Paleoenvironmental reconstruction of these environments in ancient volcanic terranes is hampered by the lack of unequivocal volcanological or sedimentological criteria that indicate water depth. The relationships established here using modern seafloor observations provide important constraints on the paleoenvironmental setting of ancient volcanic-hosted massive sulfide deposits.

<p>The calculation, analysis and interpretation of seismic attributes is an important tool in reservoir seismology and has been used since the 1950’s to improve the characterization of oil and gas fields around the world.</p><p>Recent applications of seismic attributes in the near surface use the coherency attribute to detect faults as well as average and normalized frequencies and similarity to map ground instability and image sinkholes. Seismic attributes are also used to assess unconsolidated oil sand reservoirs, to evaluate ocean/lake bottom responses from unconsolidated sediments, and to visualize the internal structure of mass transport deposits. In unconsolidated near-surface sediments seismic attributes are rarely used. This is likely due to the high variability present in the near surface.</p><p>Combined P-/S-attributes are difficult to obtain because of the large difference between P-wave and S-wave velocity, as well as frequency and resolution. Therefore, the most important step to obtain these combined attributes is performing depth conversions for the P- and S-wave reflection profiles that perfectly match horizons and features in the depth domain.</p><p>We present commonly used attributes calculated from a shear-wave reflection profile imaging the dome structure of an esker. Attributes calculated from the compressional-wave reflections are compared to the shear-wave attributes which benefit from higher resolution than P-wave attributes. We highlight the attributes which best enhance the general subsurface structure and list new information gained from different attributes.</p>

In order to develop three new deep water fields using the FPS that haveproved technically efficient and cost effective over the last 16 years, Petrobras has had to find new ways of installing export pipelines for existingdevelopment in water depth of up to 725 meters using economically attractiveand technically sound methods. The hybrid rigid/flexible combination export pipeline method was engineeredand successfully put into practice in less than 8 months for the deepest gasexport line ever installed. After the successful installation of the 8 inch gas line in 625 meters ofwater depth on the Marlim field, 5 other such pipelines are to be installed in1993, ranging from 12 inch in 340 meters to 8 inch in 725 meters waterdepth. This paper presents the various phases of engineering, fabrication andinstallation consisting in recovering a prelaid steel pipe in a "J"configuration to add in the final segments of flexible flowline and riser withany above surface connection. The method was based in using available vessels and standard tooling, toavoid costs and risks linked to the development of new deep water connectiontools and technology. The operational and economical benefits of the method are addressed as wellas its potential evolutions. Introduction Petrobras has become over the last 16 years, the leader in deep waterproduction technology, starting with the development of the Enchova field in100/150 meters water depth back in 1977 to the present Marlim/Barracuda/Bijupira and Albacora developments in the 600/900 meters water depth range. Such increase in water depth has not been attained without substantialinnovative thinking, fast decision making and a certain credence in applicationof new technology. The true pioneering spirit is alive and well at Petrobrasand has proved efficient over the years. Stepping out the continental plateau in water depths far and beyond diveraccess, further and further away from existing production and gatheringnetworks has required innovative thinking to remain cost efficient, pushingexisting and proven technology to new frontiers.

Water on road surfaces significantly degrades the available skid resistance. Indeed, 25% of injury accidents occur on wet roads in France due to lack of skid resistance. Some research results advocate an exponential decrease in skid resistance with increase in water depth. The above conclusions show the importance of knowing the water depth present on road surfaces during and after rainfall events in order to evaluate the available skid resistance for driver safety. In this paper, a prediction model of water depth on road surfaces during and after rainfall events is presented. This model takes into account the road surface characteristics such as macrotexture, slope and porosity, and weather conditions such as temperature, wind speed, relative humidity and rainfall rate. The model is based on the kinematic wave simplification of the Saint Venant equations, which represents the balance of flows from rainfall, run-off, infiltration and evaporation. The model is validated from comparisons to experimental measurements of water depth performed on four different surfaces of the IFSTTAR test track. The experimental device for the validation is composed of sensors that measure water depth, rainfall intensity, wind velocity, air humidity and temperatures. The model predictions on these four surfaces are very satisfactory.

In the current energy shortage and transition context, gas represents an alternative to provide an affordable, reliable and less GHG emissions issuing energy than other available fossil energies. Flow Assurance studies have been launched for a series of gas fields to identify optimal subsea processing functional requirements for a subsea to shore export. The objective is to confirm the robustness of subsea processing architectures identified in previous studies and to evaluate their sensibility towards water depth, step-out, fluid composition and bathymetry. First, real gas fields were selected, the portfolio was completed with notional cases constructed on analogs to reach a good mapping in depth and distance to shore. For each case, bathymetries and PVT models were established. Ledaflow® was used to construct flow models and define the necessary pipeline size based on early and late life flowrates (based upon Erosion Velocity Ratio, Turn down and hydrate risk). When the multiphase export required several pipelines in parallel, an alternative architecture was studied consisting of multiphase pipeline at early life and then gas/liquid separation plus single phases export (separated gas pipeline and liquid pipeline) for late life. Compression and boosting requirement were evaluated. More than one configuration is technically possible. The solution of "multiple multiphase export pipelines" is usually in competition with a "single multiphase pipeline at early life coupled with a subsea separation at late life". The first configuration favors operational flexibility, while the second one favors reduced installation time and cost and allows decreasing the well head back pressure to increase reserves. However, this last solution still requires the installation of a liquid line at late life. Regarding boosting requirements, each configuration has compression needs at late life. The first architecture allows to optimize the compression requirements and increase the process efficiency, while the second one present the drawback of high boosting requirements for the liquid line for great depth and longer step out. For the multiphase export, and a field with very low CGR, the governing parameter for the pressure loss and the compression requirements is the step-out, not the water depth, while, for the subsea separation scheme, the water depth becomes detrimental for the boosting requirements of the liquid line for the great water depths. This large study confirms the feasibility of subsea to shore architectures for gas fields and allows identifying the limitations of the existing technologies and anticipating future technological developments.

Although large-scale transformation of Everglades landscapes has occurred during the past century, the patterns of association among hydrologic factors and southern Everglades freshwater marsh vegetation have not been well-defined. We used a 10-year data base on the aquatic biota of Shark Slough to classify vegetation and describe plant community change in intermediate- to long-hydroperiod Everglades marshes. Study area marsh vegetation was quantitatively grouped into associations dominated by 1)Cladium jamaicense, 2) a group of emergents includingEleocharis cellulosa, Sagittaria lancifolia, andRhyncospora tracyi, 3) taxa associated with algal mats (Utricularia spp. andBacopa caroliniana), and 4) the grassesPanicum hemitomon andPaspalidium geminatum. During the decade evaluated, the range of water depths that characterized our study sites approached both extremes depicted in the 40-year hydrologic record for the region. Water depths were near the long-term average during the mid-1980s, declined sharply during a late 1980s drought, and underwent a prolonged increase from 1991 through 1995. Overall macrophyte cover varied inversely with water depth, while the response of periphyton was more complex. An ordination analysis, based on plant species abundance, revealed that study area vegetation structure was associated with hydrologic patterns. Marsh plant community structure showed evidence of cyclic interannual variation corresponding to hydrologic change over the decade evaluated. Lower water depths, the occurrence of marl substrates, and high periphyton cover were correlated. These factors contributed to reduced macrophyte cover in portions of the study area from which water had been diverted.

Many plots for soil loss measurements are equipped with a sequence of tanks for measuring runoff volume and sediment concentration. The stored water volume is easily determined by a water depth measurement while the sediment concentration is often measured by collecting samples of the mixed suspension. In this paper, using the Π-theorem of dimensional analysis, the functional relationship describing the mixing of the suspension in the tank is expressed in a dimensionless form. The recognized dimensionless groups allow the establishment, for given soil and water depth in the tank, of the relationship (calibration curve) between the actual and the measured concentration. The calibration curve, using measured concentration values obtained from sampling taps located at different heights on the vertical of a tank wall, is shown to be linear. For a given soil, the slope of the calibration curve is related to the water depth. We also show that the same dimensionless groups allow the deduction of a scale-up procedure and the possibility of using a small tank, similar to the field one, for investigating additional effects neglected in the theoretical analysis. The effects of the following factors on the calibration curve are examined: (1) sampling direction along the vertical, i.e. starting the sampling from the upper tap to the lower one or vice versa; (2) mathematical shape of the concentration profile; (3) representativeness of the calibration cufve; (4) sampling volume; (5) water depth into the tank (i.e. filling level); (6) suspension mixing time; (7) grain size distribution of the eroded soil particles for given soil type; (8) time between the end of the erosive event and the starting of the sampling procedure (delay time). Finally, an attempt is made to define a simpler sampling procedure based on a single measurement with a dipped sampler. Copyright © 1998 John Wiley & Sons, Ltd.

This paper discusses pre-lay survey work and the difficult conditions found along the deepwater portions of the Jolliet pipelines. Water depths range from about 1760 ft at the TLWP in Green Canyon Block 184 to about 616 ft at the CPP in Green Canyon Block 52, a straight-line distance of about 9 miles. Several surveys were required to adequately define conditions and find acceptable routes. A total of 380 line-miles of geophysical survey work was done during two surveys in 1986 and 1987, and 30 piston cores were taken. A small amount of geophysical survey work was done in 1988, and an ROV survey for visual confirmation of conditions in a rocky area was done in 1989. Difficult conditions include: irregular, rocky seafloor with sharp relief of tens of feet; fault scarps as much as 240 ft high; and areas of possible landslides. Because of these difficult conditions, the original proposed pipeline route was changed and the length of flexible pipe was increased. Geophysical survey tools included: a narrow-beam water-depth recording system with velocipede calibration; a scale-corrected side-scan sonar system; a 3.5-kHz shallow-penetration profiler; a one-kilojoules intermediate-penetration profiler; and a seismic Control Module to reduce vertical exaggeration in rugged topography and increase horizontal resolution. A 10- to 20-ft-Iong piston corer was used for soil sampling. The difficult conditions encountered on this project are expected to be common in some other deepwater areas. Simple, straight-line pipeline routes connecting two points will not always be feasible. Consequently, schedules and approaches that have become customary for pipeline route surveys in less than 600-ft of water in the Gulf of Mexico may not be adequate for many deepwater pipelines. Careful planning, special survey tools, more detailed surveying, and more time for data collection and analysis may be needed. INTRODUCTION This paper discusses the planning and execution of the pre-lay geohazards pipeline route surveys for the deepwater portions of the Jolliet pipelines and the analysis of difficult conditions found along the routes. This paper also discusses why the conventional approach to pipeline route surveys will not always be adequate in deepwater, and points out considerations for future deepwater pipeline route investigations. In this paper the terms "deepwater" and "continental slope" are used interchangeably and indicate water depths in excess of 600 ft. The term "continental shelf" refers to areas where water depths are less than 600 ft and the seafloor is generally flat and featureless. This paper is mostly restricted to discussion of the geophysical survey work and piston coring for the process gas and process oil/ water pipelines extending about 12.2 miles between the Tension Leg Well Platform (TLWP) production platform in Green Canyon Block 184 and the Central Processing Platform (CPP) in Green Canyon Block 52 (Figs. 1 and 2). Geophysical survey work was carried out in 1986, 1987, and 1988. Visual inspection of a rocky section of the route was done in 1989 using an ROV, but detailed discussion of this ROV work is beyond the scope of this paper. Difficult conditions along the deepwater portion of the 12-in.

Effects of nutrients and water levels on emergent macrophyte biomass in a prairie marsh