Fluid Column Research Articles

A venting resonator emitting monochromatic periodic traveling waves in dispersive media

Dynamically stable traveling periodic waves are notoriously difficult to realize experimentally. Manifestations of such waves inherently become unstable in any dispersive medium, whether it be at continuum length scales in fluid mechanics, in electrodynamics, or in nonlinear optics. Here, a simple experimental system is proposed where Stokes waves are emitted from a resonator whose cavity accommodates standing waves of same wavelength that is emitted out. A single characteristic wavelength is found for each driving frequency despite the coexistence of standing and traveling waves, external noise, and potentially parasitic reflections. The system's response is shown to be reliable at very small values of quality factor. A unique utility of this model system is suggested in that such a venting resonator can be used as an inhibitor of modulation instability in dispersive medium where an engineering application demands stable periodic traveling waves. Some parallels are drawn with other unbounded resonators found in society, whereby their leakiness is central to their application, such as the role of air-filled cavity to achieve impedance matching in stringed musical instruments, or energy harvesting from oscillating fluid columns in nature.

Solution Enables Well Surveillance in Stacked Reservoirs With Near-Critical Fluids

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 23912, “Digital Solution for Well Surveillance in Stacked Reservoirs With Near-Critical Fluid Systems,” by Kristian Mogensen, SPE, Carlos Mata, SPE, and Swarjit Samajpati, ADNOC, et al. The paper has not been peer reviewed. Copyright 2024 International Petroleum Technology Conference. _ Fully compositional integrated asset models (FC-IAMs) are being deployed for an increasing number of fields in the operator’s portfolio. The complete paper describes the development of comprehensive digital well surveillance and field-production optimization for an offshore field consisting of four stacked reservoirs, each containing near-critical fluids. Augmenting the FC-IAM with high-frequency sensor data in addition to proprietary tools to actively monitor well performance helps identify and pursue opportunities to maximize oil production from the field, subject to several system constraints. Introduction The field is approximately 120 km offshore Abu Dhabi. During the appraisal phase, eight wells penetrated the structure and confirmed that the predominant lithologies are composed of dolomite and anhydrite, with subordinate limestone. Production of oil and gas comes from four main reservoirs—A, B, C, and D. The ongoing development centers around miscible gas injection along the crestal part of each reservoir and peripheral water injection. Integrated asset models are one of many key initiatives supporting the operator’s Smart Production Growth initiative. Although the calculations identifying scope for improved production rates are firmly founded in science, substantial digitization efforts are required to automate, streamline, and sustain any such digital solution. Fig. 1 illustrates the fact that company database management plays a fundamental role in providing reliable input to keep models updated and fit for purpose. Fluid-Property Modeling Each of the four producing reservoirs contains near-critical fluids exhibiting a steep compositional depth gradient, which means that the solution gas/oil ratio (GOR) is well-specific and may change over time. The GOR trend is governed by several factors. The lightest part of the fluid column may be produced first because of the improved mobility; this would lead to a decreasing solution GOR over time. However, because of the crestal miscible gas injection, significant swelling will result in a gradual GOR increase followed by gas breakthrough. Solution GOR increases because of gas swelling. It is important to make the distinction between solution gas and free gas because the operational guidelines dictate that the reservoir pressure should be maintained above the saturation pressure and above the minimum miscibility pressure. Well-Test Validation Workflow The compositional framework adds an extra layer of complexity because fluid composition needs to be specified at the well level. A robust procedure is needed to first assign an initial reservoir fluid composition to each well. The second key task is to capture changes over time. The method of solution is referred to as a target GOR calculation. For any given fluid system, an equation of state (EOS) model must be tuned to experimental data to convert compositional information to black-oil properties at specific pressures and temperatures. A so-called anchoring fluid composition initially is assigned to the well, and the EOS can then calculate the resulting GOR and other variables from a simulated separator test. The evolved gas and liquid phases are then recombined mathematically to match a measured GOR from a production test. Matching is an iterative process but normally converges very quickly.

Acoustic radiation force on a cylindrical composite particle with an elastic thin shell and an internal eccentric liquid column in a plane ultrasonic wave field

Abstract A model with three-layer structure is introduced to explore the acoustic radiation force (ARF) on composite particles with an elastic thin shell. Combing acoustic scattering of cylinder and the thin-shell theorem, the ARF expression was derived, and the longitudinal and transverse components of the force and axial torque for an eccentric liquid-filled composite particle was obtained. It was found that many factors, such as medium properties, acoustic parameters, eccentricity, and radius ratio of the inner liquid column, affect the acoustic scattering field of the particle, which in turn changes the forces and torque. The acoustic response varies with the particle structures, so the resonance peaks of the force function and torque shift with the eccentricity and radii ratio of particle. The acoustic response of the particle is enhanced and exhibits higher force values due to the presence of the elastic thin shell and the coupling effect with the eccentricity of the internal liquid column. The decrease of the inner liquid density may suppress the high-order resonance peaks, and internal fluid column has less effects on the change in force on composite particle at ka > 3, while limited differences exist at ka < 3. The axial torque on particles due to geometric asymmetry is closely related to ka and the eccentricity. The distribution of positive and negative force and torque along the axis ka exhibits that composite particle can be manipulated or separated by ultrasound. Our theoretical analysis can provide support for the acoustic manipulation, sorting, and targeting of inhomogeneous particles.

A multilayer shallow water model for polydisperse reactive sedimentation

A three-dimensional model of polydisperse reactive sedimentation is developed by means of a multilayer shallow water approach. The model consists of a variety of solid particles of different sizes and densities, and substrates diluted in water, which produce biochemical reactions while the sedimentation process occurs. Based on the Masliyah–Lockett–Bassoon settling velocity, compressibility of the sediment and viscosity of the mixture, the system of governing equations is composed by non-homogeneous transport equations, coupled to a momentum equation describing the mass-average velocity. Besides, the free-surface depicted by the total height of the fluid column is incorporated and fully determined through the multilayer approach. A finite volume numerical scheme on Cartesian grids is proposed to approximate the model equations. Numerical simulations of the denitrification process exemplify the performance of the numerical scheme and model under different scenarios and bottom topographies.

Isolation, characterization and therapeutic potential of a novel furanoid diterpene lactone from Hedychium spicatum rhizomes: Insights into antioxidant, anxiolytic, and circadian rhythm modulating properties

BackgroundHedychium spicatum rhizomes is widely used in ayurvedic medicine and traditional medicine systems around the Himalayas. PurposeStandardization of Hedychium spicatum rhizome SCFE extract by Identification, Isolation, characterization, and screening of pharmacological activity of phytoconstituents. Study designSupercritical fluid extraction, column chromatography, spectroscopic analysis, in-silico, and in-vivo study of compound 1 (3-((E) -2-((1S,8aR)-3,5,5,8a-tetramethyl-4-oxo-1,4,4a,5,6,7,8,8a-octahydro-naphthalen-1-yl) vinyl) furan-2(5H)-one). MethodsA supercritical fluid extract was prepared and further purified to obtain a novel Furanoid diterpene lactone compound 1 (3-((E) -2-((1S,8aR)-3,5,5,8a-tetramethyl-4-oxo-1,4,4a,5,6,7,8,8a-octahydro-naphthalen-1-yl) vinyl) furan-2(5H)-one). It was characterised using IR, LC-ESI/MS, 1H, 13C NMR, 2D NMR-COSY, NOESY, HMBC, and HSQC and thin-layer chromatography. Compound was tested for anxiolytic activity using various animal behavioural model included elevated maze plus test, light and dark box test, social interaction, actophotometer test, rotarod test. ResultsThe compound gives a false Dragendorff's test in favour of the presence of lactone. HPLC profiling was done using DAD using 30 % v/v of o-phosphoric acid (0.1 % v/v) in water and 70 % v/v of acetonitrile (ACN) in the mobile phase. Compound 1 having significant anxiolytic effect tested in animal behavioural model ****p < 0.0001 diazepam as standard. ConclusionFree radical scavenging activity suggested that compound 1 has good potential as an antioxidant, having IC50 values of 75.62 µg and 96.556 µg using DPPH and ABTS inhibition assays. ADMET prediction suggested that compound 1 follows Lipinski's rules of five, absorbed through the intestine, and penetrates the blood-brain barrier and CNS. In-silico studies, suggested that compound 1 has an affinity to bind with GABA, melatonin 1, and glutamate receptor 5 and In-vivo study suggest compound 1 will be a good candidate as anxiolytic agent. It can be used as a promising natural remedy for oxidative stress, mental health issues, and sleep-related disorders, warranting further exploration and clinical investigation.

P‐86: Prediction of Droplet Behavior in Piezoelectric Inkjet Printing Based on Waveguide Theory

In the present study, we numerically investigate the effect of sub‐pulse addition on the applied voltage waveform on the high‐speed jetting procedure of drop‐on‐demand inkjet printing. The concept of a waveguide was adopted to model the reflective and interference properties of sound waves in complex geometrical layout of the pump structure partially surrounded by the piezoelectric actuator. We proposed a nonlinear model in which the mass is concentrated in points by dividing the fluid column and the connecting duct inside the pump section into equal‐sized volumetric elements. A three‐dimensional finite volume numerical simulation was performed for the solution of the Navier‐Stokes equation based on the volume‐of‐fluid method for tracing the fluid interface. The negative part of the bipolar waveform acts as a suction‐removal residual pressure, suppressing the satellite, while the positive voltage repels the meniscus and separates the liquid from the meniscus. The present method based on waveguide theory was successfully applied to evaluate the effect of multi‐step waveform voltage in terms of maximum velocity, size, satellite generation, ligament length.

Anti-Inflammatory and Anti-Arthritis Activity of Quercetin: A Comprehensive Review.

This comprehensive exploration delves into the multifaceted attributes of quercetin, a flavonoid with extensive health-promoting potential. The review navigates through its fundamental properties, encompassing its chemical structure, classification as a flavonoid, and its natural prevalence in various sources. Addressing solubility, stability, and bioavailability challenges, the investigation delves into innovative isolation techniques, including solvent extraction, solid-phase extraction, natural deep eutectic solvents, supercritical fluid extraction, microwave-assisted extraction, column chromatography, and high-performance thin-layer chromatography. Transitioning into pharmacological implications, the study unveils quercetin's roles in anti-inflammatory pathways, antioxidant effects, and immune modulation, reflecting its versatile significance in health management. The review highlights its impact on wound healing processes and its potential to mitigate arthritis, elucidating its holistic contributions. Culminating in an exploration of recent studies, the analysis underscores quercetin's remarkable anti-inflammatory and anti-arthritis activities, reflecting its substantial potential across various ailments. The review concludes by projecting future trajectories, emphasizing prospects for an advanced understanding of quercetin's mechanisms, sustainable extraction techniques, clinical integration, and exploration of synergistic combinations. Collectively, this review investigation underscores quercetin's dynamic role at the intersection of natural compounds and medicinal applications, offering profound implications for well- being and health enhancement.

Sand fill cleanout on wireline enables access to additional perforation zones in gas well producer

An Australian operator wanted to explore options for wireline conveyed sand bailing in one of their offshore deviated ‘S’ shape gas producing wells. The objective was to remove approximately 24 m of sand fill inside 9.625″ production casing, with an internal diameter (ID) of 8.681″. To limit the number of cleanout runs, the latest technology in wireline deployed suction tools with a 4.25″ overall diameter (OD) was chosen, which provided increased recovery volume, plus real-time surface control and monitoring. Because of the tool’s overall diameter, the landing nipple also required milling to allow access. Therefore, a specially designed 4.412″ mill bit was manufactured and run on a milling tool. The electric line deployed milling technology successfully milled through the landing nipple and a ball catcher in four runs, thus increasing the ID sufficiently to allow access for the cleanout tool string. A well fluid column of about seven bars is required to enable operation of the suction tool. The cleanout tool was configured with three bailer sections (seven max) for the first run, to determine sand recovery optimisation. Three different sizes of bailer filters are provided; prior knowledge of debris particle size is therefore advantageous. In this case, a slickline bailing sand sample had been recovered, which immediately aided filter choice. Seventeen bailing runs were conducted over 5 days, successfully recovering a total of 918 L of sand, equating to about 2.4 tons. Ultimately, the process enabled perforation of two additional gas zones to increase production.

Short-period flow oscillation during eruptions of Onikobe geyser, NE Japan: Insights from thermal infrared observation and acoustic measurements

Geysers are episodic features with variable eruption intervals that range from minutes to years. Although many previous studies on geysers have focused on subsurface properties and processes such as plumbing geometry and recharge process, it is known that erupting fluid column exhibits short-term behaviors such as individual water jets from the vent. In the present study, we conducted observations at Onikobe geyser, NE Japan, a relatively small geyser (geysering well) erupting water up to ∼6–8 m every ∼10 min and observed the erupting fluid column using a thermal infrared camera and an acoustic sensor. We succeed in tracking the water jets by analyzing spatio-temporal temperature map obtained from the thermal infrared observation, which clearly shows the eruptions at Onikobe geyser are not completely stationary but rather a series of intermittent jets with a short period interval of <1 s. We estimate the exit velocity by fitting a ballistic model under the air drag condition of inertial resistance to the jet trajectory. The exit velocity and the averaged gas volume fraction of the erupting fluid are estimated to be ∼4–79 m/s and ∼0.93–0.96, respectively. The exit velocity is ∼30 m/s during the first bursts, then it rapidly increases to ∼50–80 m/s for ∼15 s, and then decreases to ∼20–30 m/s until ∼10 s before the eruption ends. Time series analyses of the thermal infrared and acoustic signals during an eruption indicate harmonic spectra with integer multiple peaks. The fundamental frequency showing ∼4 Hz at the beginning gradually decreases to ∼2 Hz for ∼15 s, keeps almost constant in the following 30 s, and then slightly increases near the end of the eruption. These harmonic spectra may be caused by a resonance mechanism, non-linear fluid motion, and/or subsurface two-phase flow. We discuss the case of a closed organ-pipe resonance in a subsurface crack and attribute the frequency decrease to a decrease in the water level in the crack (an increase in the length of the resonating liquid-vapor column) and/or a decrease in the gas volume fraction of the liquid-vapor mixture in the crack. Since such harmonic characteristics are observed at other geysers, further simultaneous observation of the short-period oscillations on the erupting column proposed in this study with seismic observations of harmonic tremor may provide an improved understanding of geyser subsurface phenomena.

Sound escapes any gravity well

The principle of mechanical energy conservation limits the height at which a body of mass m and initial total mechanical energy Ei can get in a uniform gravitational field g, namely hmax=Ei/mg . However, the same conservation principle does not pose any limit to the height reachable by a sound wave in a vertical column of (ideal) fluid in the same uniform gravitational field. Here, we provide two accessible proofs of a counter-intuitive result that can represent an amusing digression from the usual presentation of the topic.

Energy absorption from an oscillating fluid using an engineered acoustic diode

Over the past decade, engineered subsurface structures inspired by acoustic metamaterial configurations have shown promising results in boundary layer control through different energy stabilization mechanisms. Despite the potential shown via numerical simulations, the underlying interfacial dynamics between a fluid column and a compliant metamaterial remain largely unexplored. Our preliminary studies have shown that conventional phononic band gaps are insufficient for effective control since the bulk of the absorbed energy remains confined to the fluid-structural interface, a direct consequence of localized modes associated with band gap truncation resonances. In this talk, we will discuss the mathematical intricacies of impedance boundary conditions (IBCs) at the interface of a one-dimensional fluid and an engineered structure, shedding light on both linear and non-linear subsurface behaviors. Through which, we will present a new pathway to effectively transmit a pressure wave from an oscillating fluid away from the interface, and into a structural medium.

Machine learning‐enabled optimization of melt electro‐writing three‐dimensional printing

AbstractMelt electrowriting (MEW) is a solvent‐free (i.e., no volatile chemicals), a high‐resolution three‐dimensional (3D) printing method that enables the fabrication of semi‐flexible structures with rigid polymers. Despite its advantages, the MEW process is sensitive to changes in printing parameters (e.g., voltage, printing pressure, and temperature), which can cause fluid column breakage, jet lag, and/or fiber pulsing, ultimately deteriorating the resolution and printing quality. In spite of the commonly used error‐and‐trial method to determine the most suitable parameters, here, we present a machine learning (ML)‐enabled image analysis‐based method for determining the optimum MEW printing parameters through an easy‐to‐use graphical user interface (GUI). We trained five different ML algorithms using 168 MEW 3D print samples, among which the Gaussian process regression ML model yielded 93% accuracy of the variability in the dependent variable, 0.12329 on root mean square error for the validation set and 0.015201 mean square error in predicting line thickness. Integration of ML with a control feedback loop and MEW can reduce the error‐and‐trial steps prior to the 3D printing process, decreasing the printing time (i.e., increasing the overall throughput of MEW) and material waste (i.e., improving the cost‐effectiveness of MEW). Moreover, embedding a trained ML model with the feedback control system in a GUI facilitates a more straightforward use of ML‐based optimization techniques in the industrial section (i.e., for users with no ML skills).

Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure

Sustained Casing Pressure (SCP) is the persistent casinghead pressure resulting from the well’s annular integrity loss and migration of gas above the leaking cement sheath. Downhole—intervention methods for SCP removal employ workover rigs to access and plug off the leaking annulus at depth from within the well. The inexpensive rig-less method of Buoyant Kill involves surface injection of immiscible heavy fluid at the casinghead into the well’s annulus to replace the annular fluid column above the gas-leaking cement and stop gas migration. Laboratory and pilot-size testing have shown feasibility of the method. Presented here, is a field-scale demonstration experiment conducted in a pressurized 2750-foot well with water displaced by an immiscible brominated organic fluid over 20-h long operation. Discussed is experimental design supported by fluid selection study, benchtop and pilot tests, and fluid transport model. Also analyzed is the process performance and operational problems. The results confirm feasibility of the Buoyant Kill technique for SCP removal. The overall change of the wellhead and downhole pressures follows the expected patterns indicating partial removal of the simulated SCP. The removal is incomplete due to pumping pressure pulses and wellhead pressure variations resulting in some emulsification of the two fluids and partial loss of the injection fluid into the overflow. The results show that wellhead pressure control and injection pump operation are critical for successful SCP removal using the Buoyant Kill technique.

Refinement of intrathecal catheter design to enhance neuraxial distribution

BackgroundDelivery of therapeutics via indwelling intrathecal catheters is highly efficacious for targeting of pain, spasticity, neuraxial cancer and neurodegenerative disorders. However, current catheter designs have some major limitations. Given limited CSF flow, fixed intrathecal volume and the large distance of the rostro-caudal spinal axis, current intrathecal delivery routes fail to achieve adequate drug distribution. Additionally open catheter systems are plagued with cellular ingrowth and debris accumulation if used intermittently. New method1.We addressed these issues by designing a new catheter that includes micro-valves2.Micro-valves distributed along the catheter open simultaneously upon adequate local transmural pressure, which is evenly distributed along the catheter fluid column.3.Buildup of transmural pressure, prior to microvalve opening, results in increased solute exit velocity.4.Micro-valves are closed when not in use, preventing anything from entering the system, and allowing for long-term intermittent use. Results/comparison with existing method(s)High speed imaging showed micro-valve catheters greatly increase fluid exit velocities compared to typical open-ended catheters, which prevents pooling of injectate proximal to the opening. When implanted intrathecally in rats, small injection volumes (7.5 μL) of dye or AAV9-RFP, resulted in an even rostro-caudal distribution along the spinal axis and robust transfection of neurons from cervical to lumbar dorsal root ganglia. In contrast, such injections with an open-ended catheter resulted in localized distribution and transfection proximal to the delivery site.Our poly micro-valve catheter design resulted in equivalent transfection rates of cervical DRG neurons using 100x lower titer of AAV9-RFP. Unlike open port catheters, no debris accumulation was observed in the lumen of implanted catheters, showing potential for long-term intermittent use. ConclusionsThis catheter platform, suitable for small animal models is easily scalable for human use and addresses many of the problems observed with common catheter systems.

Three-dimensional analytical solution of free vibrations of a simply supported composite plate in contact with a fluid

Background:The quantification of fluid–structure interactions is critical for the design and optimization of marine structures. As composite materials gain more traction in naval construction, there is a dire need of modeling tools to detail the dynamic response of composites in contact with fluids. Current structural theories and finite-element simulations offer promising pathways, but their strong hypotheses on through-the-thickness deformations and high computational cost challenge their practical feasibility. Methods:We propose an analytical three-dimensional solution to the free vibration of a bidirectional composite, separating a fluid column from vacuum. We leverage Pagano’s method to describe the three-dimensional displacement field in each ply of the composite plate and the fluid potential in the form of a Fourier series. Results:An analytical solution to the coupled fluid–structure problem is derived by imposing the continuity of displacement and stress at the ply interfaces, as well as boundary conditions on dry and wetted plies. We specialize the solution to sandwich structures of naval interest, offering insight on how the interactions with water can dramatically affect mode shapes and through-the-thickness profiles of displacement and stress. Discussion:The proposed approach provides the foundations for the design of thick composite plates for use in marine structures.

Evaluation of different well control methods concentrating on the application of conventional drilling technique

Over the past few decades, engineering failures have existed, and lack of knowledge, and safety practices have led to various catastrophic events of blowouts causing countless casualties and injuries to workers and individuals all around the world. Well control is a technique in oil and gas activities specifically when drilling oil and gas wells. Hydrostatic pressure and formation pressure should be a priority to prevent reservoir fluids from infiltrating the wellbore. The primary well control is commonly the primary barrier using the fluid column to prevent uncontrolled formation fluid flow into the wellbore by preserving pressure more substantial than formation pressure. The secondary well control provides the same purpose but involves using a piece of equipment known as a Blowout Preventer. The objective of this paper is to evaluate the effectiveness of different well control techniques of various well control methods, including the commonly used in petroleum engineering focusing on the application of conventional drilling. This study was conducted through a literature review. The analysis of the case studies synthesized to provide a comprehensive overview of the various well control methods. The findings suggested that conventional drilling techniques can be effective in controlling wellbore pressures, however, limitations existed in certain situations. Moreover, the parameters required controlling the well during a kick or a blowout is discussed to succeed in the application of well control methods in the oil and gas industry.

Study on the Formation and Controllable Movement of Polymer Liquid Columns Based on Dynamic Control of Spatial Electric Field Distribution.

Liquid deformation and motion are very common natural phenomena and of great value in various practical applications. In this study, a dielectric fluid column formation and directional flow phenomenon are presented. Dielectric fluid can grow upward to form a liquid column through a spatial electric field and realize directional and controllable operation of the liquid column by regulating spatial electric field distribution. First, the adjustable electric field space is constructed by connecting the two parallel electrodes to the high-voltage DC power supply. Then, the regional electric field distribution was adjusted by the upper plate graphic and power supply regulation to drive the polymer liquid on the lower plate electrode to form a liquid column at different positions. The results show that the polymer liquid column can be driven by the spatial electric field distributed dynamic control method and that the height and the narrowest width of the liquid column are directly controlled by the voltage. With the experiment conditions that the distance between two parallel electrodes is 5-15 mm, the formation of liquid columns with a height of 5-15 mm can be controlled. In addition, the liquid column can be driven by adjusting the on-states of different conductive regions. When the voltage is 10 kV, the liquid column directional movement speed can reach 1 mm/s. The higher the voltage, the faster the directional movement. The research results can be used as producing polydimethylsiloxane stamp, localized heating and temperature control, fabricating a pulsating heat pipe, and so on.

Blowout-Capping-Fracturing-Relief Well: A Full Cycle Workflow

Summary Failed well-capping attempts following offshore-well blowouts undergoing worst case discharge (WCD) can lead to fluid-driven tensile failures (de facto hydraulic fracture initiations). Subsequent propagation of these fractures may lead to broaching of overburden-rock-formation layers and even the seafloor, providing pathways for reservoir hydrocarbons to escape into the seawater. After capping stack shut-in, the pressure buildup in the fluid column inside the wellbore exposes vulnerable locations to tensile (Mode I) failure. If this shut-in wellbore pressure exceeds the formation breakdown pressure (FBP) in any of the exposed-rock-formation layers, a fracture will initiate and will continue to propagate as long as sufficient energy is provided by the reservoir. Scenarios where the propagating fracture(s) broached the seafloor in the past led to severe environmental impacts, disturbing the local ecology. The quintessential example is Union Oil’s 1969 “A-21 Well” blowout in California’s Santa Barbara Channel, where subsequent well-capping attempts led to multiple broaching instances on the seafloor near the well with thousands of hydrocarbon gallons gushing into the seawater (observable from the sea surface as “oil boilups”). In this paper, numerical modeling is performed on a hypothetical case study using deepwater Gulf of Mexico parameters in order to evaluate the likelihood of a similar scenario by modeling a planar-fracture propagation longitudinally-to-the-wellbore, upon well capping. A workflow is developed that integrates post-blowout WCD flowrate and volume estimations, fracture initiation and propagation modeling following the capping stack shut-in, pertaining to a “cap-and-contain” strategy (including predictions in regard to seafloor broaching), along with relief-well intersection followed by kill-weight-mud injection. The casing-shoe depth is the presumed location of fracture initiation, assuming perfect integrity of all casedhole sections above it. Several sensitivity analyses are performed to investigate the impact of the casing-shoe depth, along with the stiffness of the overburden-rock-formation layer, and the post-blowout-discharge duration on the resultant fracture growth. Finally, the mud density and pump flowrate necessary to compensate the oil column to successfully kill the blown well are quantitatively assessed.

Estimation of Temperature Profiles using Low-Frequency Distributed Acoustic Sensing from In-Well Measurements

Summary Distributed fiber-optic sensing for in-well measurements is primarily used for monitoring purposes. Distributed acoustic sensing (DAS) is used to record acoustic disturbances and is sensitive to changes in strain, pressure, and temperature. Distributed temperature sensing (DTS) is used to measure temperature along the fiber. Here, we compare temperature changes measured by DAS and DTS in wells over different time periods. We affirm the linear dependency between DAS’s phase change and temperature, with the derived strain rate being proportional to the time derivative of the temperature response. Given that low-frequency (LF) DAS is sensitive to strain, pressure, and temperature effects, one must choose quiet periods in the well or condition the data to only analyze the effect of temperature on the fiber. We show that LF-DAS data can be used to track temperature changes over several weeks. We then propose a method, using liquid column movements, to invert LF-DAS data for absolute temperature profiles. The temperature profile in a well can be measured using DTS. However, DTS data are not always available, and conventional Raman scattering DTS is not used in subsea wells with long lead-in lengths. Hence, it would be desirable to acquire the temperature response from LF-DAS data to use as a multipurpose tool for in-well monitoring. Here, we show that when purely investigating the response to an initial displacement of the fluid column (i.e., from rest), LF-DAS can be used along with reference sensors, such as the wellhead and downhole temperature gauge data to estimate the depth variations in temperature in production and injection wells.

Vertical Structure of Buoyancy Transport by Ocean Baroclinic Turbulence

AbstractOcean mesoscale eddies enhance meridional buoyancy transport, notably in the Antarctic Circumpolar Current where they contribute to setting the deep stratification of the neighboring ocean basins. The much‐needed parameterization of this buoyancy transport in global climate models requires a theory for the overall flux, but also for its vertical structure inside the fluid column. Based on the quasi‐geostrophic dynamics of an idealized patch of ocean hosting an arbitrary vertically sheared zonal flow, we provide a quantitative prediction for the vertical structure of the buoyancy flux without adjustable parameters. The prediction agrees quantitatively with meridional flux profiles obtained through numerical simulations of an idealized patch of ocean with realistic parameter values. This work empowers modelers with an explicit and physically based expression for the vertical profile of buoyancy transport by ocean baroclinic turbulence, as opposed to the common practice of using arbitrary prescriptions for the depth‐dependence of the transport coefficients.