Summary We present a semi-analytical method to analyze the multistring response of tubulars in offshore wells with mudline suspension system (MLS). Though governing equations are linear, structural redundancies at hangers (MLH) require one-step iterative solution. The iteration ensures that final MLS and is consistent restrictions wellhead mudline. Our computationally simple can be implemented spreadsheet. apply an well six strings, four which suspended arranged such string transfers its...

Summary Subsea wells use annular-pressure-buildup (APB) mitigation devices to ensure well integrity. We define techniques that control APB by reducing lateral heat loss from the production tubing wellbore as Type I techniques. Mitigation stiffness (psi/°F) of an annulus modifying its contents and boundaries are defined II Although physics is well-understood, reliability a strategy or interaction with other parts not always quantifiable. This partly because lack unified approach analyze...

Abstract Subsea wells use Annular Pressure Build-up (APB) mitigation devices to ensure well integrity. Type I techniques control APB by reducing radial heat loss from the production tubing wellbore. II work controlling stiffness (psi/°F) of an annulus modifying its contents and boundaries. Though physics is understood, reliability a strategy or interaction with other parts wellbore not always quantifiable. This partly due lack unified approach analyze strategies, downhole data after...

In the fundamental (l=2) mode, frequency spectrum of a magnetically levitated inviscid droplet exhibits three distinct peaks. If modes that correspond to each these peaks is known, surface tension may be calculated. experiments make use this principle, there no unambiguous method assigning mode numbers The dynamics oscillating depend on magnetic pressure surface. Consequently, order in l=2 oscillations determined by distribution. paper, distribution calculated as function parameters govern...

Abstract Field-X is a large greenfield high pressure temperature (HPHT) carbonate development located off the coast of Sarawak, offshore Malaysia. The current plan requires each wellhead platforms (WHP) to have multiple high-rate gas wells meet Daily Contract Quality (DCQ) requirements. When closely spaced produce simultaneously, they can perturb local geothermal profile, and affect thermal response individual wells. This also impact platform pile conductor strengths, infill well designs....

Abstract On 20Apr05, while bringing Mad Dog Slot W1 back on production after a brief shut-in, pressure developed the A annulus and persisted despite repeated bleeds. Diagnostic tests logs eliminated number of possible sources pressure, eventually leading to conclusion that 9-7/8 in. tieback had been breached. Further investigative led observation ovalization tubing. This study summarizes efforts team assigned investigate causes tubing casing deformation. The outcome analysis suggests subtle...

Summary During production in prolific high-temperature wells, the forces exerted by inner strings can cause noticeable wellhead motion (WHM). The thermal created are balanced structural casing and friction between formation. Depending on shear-stress profile at structural-casing/soil interface, point of fixity (POF) may lie below mudline, gross subterranean section occur. When shut-in well cools back to undisturbed state, disappear. Because anisotropic nature frictional forces, does not...

Abstract Annular Pressure Build-up (APB) in wellbore annuli is a problem most deepwater wells. If APB induced loads compromise string integrity, the selection and design of suitable mitigation strategy must be pursued. The calculations required for such analyses can tedious, since number cases to identify key variables "what-if" scenarios evaluated. Though analytical techniques evaluate strategies are well understood, there need perform these quickly reliably. This paper discusses...

The design and development of steam-injection fields is a mature subject. Because the tubulars in these wells invariably experience inelastic loading, issues such as effects temperature on static cyclic (fatigue) material properties become important. original papers that address casing-design date back to 1960s. These studies include prediction (Leutwyler Bigelow 1965), casing-stress analysis (Willhite Dietrich 1967), guidelines (Holliday 1969). Though works acknowledge role properties, data...

A method to calculate the Lorentz force on an electrically conducting sphere placed in arbitrary sinusoidally varying magnetic field is developed. The crux of this lies expressing external held and eddy current density terms a "source function" sources "skin depth dependent function". general formula for used derive special case axisymmetric stack circular loops. Numerical results are presented as function geometry. Approximations skin functions practical situations presented. Finally,...

Abstract This paper addresses the nature and assessment of drillpipe fatigue. A detailed examination statistical analysis three published sources S-N curve data supplemented by principles machine design, provides a consistent basis to determine curves for arbitrary size grade. The design approach translates fatigue life characteristics small sample that as larger component. translation accounts size, manufacturing process influences such environment vibrations. resulting behavior agrees with...

Abstract The average geothermal gradient in the subject deepwater field Nigeria is 4.37 °C/100 m, nearly twice most fields. As a result, magnitude of expected annular pressure build-up (APB) during steady state production large enough to threaten well integrity. Therefore, an insulating packer fluid (IPF) was used Annulus A reduce heat transfer outer annuli and regulate APB within acceptable values. To gain confidence thermal analyses estimate efficacy IPF, downhole temperature sensors were...

The excitation coil used in electromagnetic-levitation melting consists of a few turns copper tubing wound over length centimeters. behavior the field and Lorentz force on conducting specimen it are studied for typical coil. equations gradient this obtained by modeling as helix surface cone. Results due to current flowing right circular presented. These results compared with an equivalent stack coaxial loops laboratory It is shown that model more realistic than 'stack loops' model. In limit...

Abstract Barite sag is the undesirable fluctuation in drilling mud density that occurs due to downhole settling of weighting agent. causes problems such as differential sticking, lost circulation, and can lead serious well control events. This paper describes a fundamental theoretical effort describe dynamic muds by considering behavior system particles non-Newtonian Bingham fluid. A continuum mechanics based model an inclined annulus presented terms fluid particle properties. The results...

Abstract Deepwater drilling trends are moving towards deeper water depths as well exploration horizons and reservoirs below the mudline. These have created various operational design challenges. This paper addresses a serious problem pertinent to of landing strings drill for deepwater operations. designed run long heavy casings, tiebacks, or liners (typically including deep intermediate production tubulars). The total weight these may approach exceed 1,000...

Abstract Current models of slip crushing treat the rotary as an axisymmetric wedge that generates radial load on drillpipe lateral surface. However, recent tests strain gauged specimens suggest this model does not adequately capture mechanical response drillpipe. The show is a complex and non-axisymmetric function geometry, friction between bowl in table, mechanics transfer This paper presents new behavior represents system series line loads. Analysis suspended tubular under these forces...

Summary Pressure testing blowout preventers (BOPs) with synthetic-based mud (SBM) requires lengthy times resulting from pressure/volume/temperature (PVT) influences associated SBM. PVT are especially pronounced indeep water and high-pressure test environments. A project was initiated in an effort to better understand the mechanics that transpired during BOP testing. The primary objective demonstrate pressure decline quantified by fluid-PVT behavior, mechanical thermodynamics of...

Abstract This paper describes the material selection for tubing in water injection wells deepwater applications. It details qualification and deployment of an alternative to duplex corrosion resistant alloy (Duplex-CRA) tubing, including testing work that was performed. Also described are operational aspects running resulting product several wells. With advance into expensive subsea wells, along with use produced re-injection historical performance de-oxygenation systems, most recent...

Summary This paper addresses a problem pertinent to the design of landing strings and drillstrings for deepwater operations. These are designed run long heavy casings, tiebacks, or liners (typically deep intermediate production tubulars), total weight may approach exceed 1,000 kilo lbf (klbf) at mudline. Adding string rotary results in serious regarding both itself handling equipment. Slip-based systems work well most instances but lead biaxial loading from tensile radial loads exerted by...

Abstract Exact solutions are presented for the circulating temperature profiles in an arbitrarily complex deepwater HP/HT well. The methodology is based on coupling multiple segments via interface matching conditions, and can handle deviated wells curvature, tortuosity, variable lithology geothermal gradients. Frictional heating both at drillbit due to Negative Joule-Thomson Effect included by flow hydraulics heat transfer. These have been largely neglected previous studies Both forward...

Abstract During production in prolific high temperature (HT) platform wells, the forces exerted by inner strings can cause noticeable Wellhead Motion (WHM). The thermal created are balanced conductor (structural casing), and finally friction between formation. Depending on shear stress profile at conductor-soil interface, point of fixity (POF) structural casing may lie below mudline (ML), gross motion subterranean section occur. When shut-in well cools back to undisturbed state, disappear....

Abstract Pressure testing Blowout Preventers (BOPs) with Synthetic-Based Mud (SBM) requires lengthy times as a result of pressure/volume/temperature (PVT) influences associated SBM. PVT are especially pronounced in deepwater and high-pressure test environments. This project was motivated by an effort to better understand the mechanics that transpire during BOP testing. The primary objective demonstrate pressure decline is quantified fluid behavior, mechanical influences, thermodynamics...

Abstract One of the documents that a drilling operator must submit with Application for Permit to Drill (APD) Bureau Safety and Environmental Enforcement (BSEE) is Well Containment Screening Tool (WCST). The data are submitted via eWell by during APD process. results screening tool used demonstrate well adequately designed contain uncontrolled flow. Worst Case Discharge (WCD) loads considered as survival loads, exposed tubulars satisfy design factor 1.0, both burst collapse loads. Two levels...