El diseño de la sarta de perforación consiste en seleccionar componentes de una lista de elementos disponibles para cumplir objetivos específicos. El proceso de diseño debe buscar tres metas principales:
Mantener el esfuerzo máximo en cualquier punto de la sarta por debajo del límite de fluencia, ajustado por un factor de diseño.
Configurar los ensamblajes para retardar la fatiga de manera económicamente práctica.
Proporcionar equipos resistentes al sulfuro de hidrógeno () si se espera su presencia.
1. Factores a Considerar
El diseño es un proceso de varios pasos que generalmente comienza en el fondo de la sarta y avanza hacia arriba. Se deben considerar:
Profundidad total, tamaño del hoyo y ángulo de inclinación.
Peso del lodo, sobre-tensión (overpull) y componentes del BHA.
Pesos y grados del acero de la tubería.
Entorno corrosivo y capacidad de recuperar herramientas en caso de pegadura.
2. Definiciones de Nomenclatura para Diseño en Tensión
Para seleccionar los grados de tubería, se debe mantener al menos el Margen de Sobre-tensión (MOP) deseado en todos los puntos de la sarta:
Capacidad de Carga a la Tensión (P): Es el esfuerzo calculado para alcanzar la fluencia del cuerpo del tubo.
Factor de Diseño en Tensión (DFT): Factor usado para reducir la capacidad nominal y obtener la Carga Permisible ().
Margen de Sobre-tensión (MOP): Capacidad de tracción adicional por encima de la carga de trabajo para compensar arrastre, pegaduras y efectos de presión.
Carga de Trabajo (): Es la tensión máxima esperada durante operaciones normales.
Nota: Al diseñar, se debe usar siempre el "peso ajustado" o "peso al aire", no el "peso nominal".
3. Pasos del Cálculo
Calcular la Carga Permisible (): .
Definir el MOP: Se basa en condiciones locales o política de la empresa. Se incluye el efecto de la presión de circulación () sobre la tensión.
Calcular la Carga de Trabajo (): .
Calcular Longitudes de Secciones: Se empieza desde el BHA hacia arriba, añadiendo una junta de tubería a la vez del grado más bajo hasta alcanzar . Luego se cambia a un grado superior.
4. Consideraciones Críticas
Aplastamiento por Cuñas (Slip Crushing): Las cuñas ejercen compresión circunferencial que puede deformar el tubo. Debe verificarse que la carga de trabajo no exceda la capacidad de compresión de las cuñas.
Presión de Colapso (Collapse) y Estallido (Burst): Se debe calcular la presión diferencial neta y corregir los valores tabulares API según la tensión axial aplicada.
Resistencia Torsional de las Conexiones: Es esencial asegurar que el torque de perforación no exceda el torque de apriete (Make-up Torque) ni la resistencia torsional de las uniones (tool joints).
Pandeo (Buckling): Se simplifica ignorando las fuerzas de estabilidad mientras hay circulación sin peso en la mecha. Sin embargo, si la caída de presión en la mecha aumenta con peso sobre ella, puede ocurrir pandeo inducido por presión. Regla de oro: Si aumenta el caudal de bombeo con peso en fondo, levante la sarta hasta notar ganancia de peso para liberar la tensión.
5. Diseño para Pozos Direccionales, Horizontales y de Alto Ángulo
En estos casos, entran en juego dos factores adicionales:
Fuerzas de fricción: Entre la sarta y el pozo.
Capacidad de proporcionar WOB (Peso sobre la mecha): Sin pandear la tubería.
El diseño debe asegurar que la carga aplicada no exceda las limitaciones mecánicas del ensamblaje. El cálculo del peso máximo sin pandeo se divide en dos:
Debajo del punto de tangente.
Por encima del punto de inicio de desviación (kickoff point).
Este marco de diseño garantiza que la sarta de perforación sea estructuralmente capaz de soportar las exigencias operativas y ambientales durante todo el proceso de perforación.
.MAS INFORMACION
- Drill String Design Calculations Steps
- Plan Well
- BHA Design In Drill String
- Drill Pipe String Design
- Tension Design Nomenclature
- Definitions
- Calculate Allowable Load
- Set Maximum Over Pull
- Calculate Working Load
- Calculate Maximum Length Of The Drill Pipe Sections
- Slip Crushing In Drill String Design
- Drill Pipes Collapse Pressure
- Drill Pipes Burst Pressure.
- Tool joint Torsional Strength
- Stability Forces and Drill Pipe Buckling In String Design
- Heavy Weight Drill pipes
- Directional Drilling String Design for Deviated wells
- Drill String Design for High Angle and Horizontal Wellbores
Well Blowout
Well blowout is an uncontrolled release of flowing fluids (e.g., gas, oil, water, and mud) from a well once pressure control systems such as BOP Stack are completely lost. This uncontrolled flow will end up with a well kick that increases in severity and may result in a “blowout”. The well control can only be recovered …
Well Control On Rigs: 15 – Checks & Tests
Check(s): Comments: BOP Control Unit pressures & leaks: Check pressures of accumulator (3000 PSI), manifold (1500 PSI) and annular (between 700 and 1500PSI subject to ‘requirements’). Check air pressure to air pumps (125 PSI). Look and listen for any leaks of air or oil. Remove the two inspection caps from the reservoir and look along …
Shallow Gas Drilling Procedure
We need to study the technical and operational aspects of top-hole drilling in the planning phase of a well. This will greatly help us provide practical shallow gas procedures for that particular well. The comprehensiveness of these drilling procedures depends on the chance of encountering shallow gas. The summary of wells with a higher probability of …
Bottom Hole Pressure In Drilling
If you’re involved in drilling operations, you know how important it is to understand the concept of “bottom hole pressure.” This term is critical for drilling supervisors, drillers, drilling engineers, and all rig personnel, as it directly impacts well control. In fact, if the BHP drops below the formation pressure, it can cause a kick …
Formation Pore Pressure In Oil & Gas Wells
Formation pore pressure is the pressure exerted by the formation fluids on the walls of the rock pores. The pore pressure supports part of the weight of the overburden stress, while the rock grains take the other part [Rabia, 1985]. Formations are classified based on the magnitude of their pore pressure gradients. In general, two …
Background Gas In Drilling Oil & Gas Wells
Background gas enters the mud circulating system as the formation is drilled by the drilling bit and usually maintains a steady but low level. Additionally, as shales are circulated up the hole, the reduction in pressure explodes the shale particles releasing gas into the drilling mud. These are the most common sources of gas. Pressure …
Shut In Drill Pipe & Casing Pressure
After taking an influx, closing the BOP stack & shutting in the well, pressure will build up on the standpipe and casing gauges. This is because of the hydrostatic under balance (drilling fluid weight too low to balance formation pressure). The pressure on the standpipe manifold is “Shut In Drill pipe Pressure” SIDPP, and what …
Underground Blowout Causes & Killing
An underground blowout is the flow of formation fluids from one zone to another. Most commonly, we can recognize the underground Blowout by a lack of pressure response on the annulus. And this response will be while pumping on the drill pipe or by a general lack of pressure response. The underground Blowout can be …
Relief Well Operations & Planning In Oil & Gas
A relief well is a directionally drilled (Directional Drilling) offset wellbore whose purpose is to intersect a well that has well control blowing out, thus enabling the control of the well blowout. Relief Well Plan The relief well plan shall contain, as a minimum: Relief Well Kill Requirement Limit Rate Modelling A relief well plan …
BOP Rams Types, Applications & Features
The BOP rams are the result of some eighty years of development in the BOP stack system. The first BOP ram was developed in the early 1900s. The ram preventer will only seal on the specific condition for which the ram block is designed. Rams are interchangeable between ram-type preventers of the same design and …
Formation Integrity Test Procedure & Calculation
FIT or formation integrity test can be defined as the application of pressure by superimposing a surface pressure on a fluid column in order to determine the ability of a subsurface zone to withstand a certain hydrostatic pressure. Why FIT? The reason for performing the formation integrity test or formation competency test is to determine …
Well Control Formulas & Illustrated Examples
This article covers all formulas that are used while well control situations on the drilling rig ( Check also: Drilling rigs Types). Pressures Formulas HYDROSTATIC PRESSURE (all depths TVD): Constants: PRESSURE, psi = Mud Weight x Constant x Depth, (TVD) PRESSURE GRADIENT, psi/ft = Mud Weight x Constant OR = Pressure, psi ÷TVD, ft MUD …
Kill Sheet Calculation Steps, Formulas & Calculators
Kill sheets are used to calculate the mud weight, mud quantities, and pumping times required to bring a well back to primary control after a gas kick. A description of how to complete kill sheets will be discussed in this article. The kill sheet is a printed form that contains blank spaces for recording information …
BOP Accumulator Requirements & Inspections
The system used for closing the BOP’s is a high-pressure hydraulic fluid accumulator unit. Hydraulic fluid is stored under pressure, the pressure being provided by stored nitrogen. When hydraulic oil is forced into the accumulator by a small volume, high-pressure pump, the nitrogen is compressed, storing potential energy. When the BOP’s are activated the pressured …
BOP Control System Components & Recommendations
A Blowout Preventer (BOP) Control System as one of the drilling rig components, is a high-pressure hydraulic power unit fitted with directional control valves to safely control well kicks and prevent blowouts during drilling operations. A typical system offers a wide variety of equipment to meet the customer’s specific operational and economic criteria. The following …
Well Control Problems & Solution While Operations
Always Be Prepared for Complications & Problems During Well Control Operations Note: If a problem develops while killing a well, “NOTE and RECORD” the drill pipe and casing pressure, stop the pump, shut in the well, and then, evaluate the situation. Well-controlling pressure is provided by using the horsepower of the mud pumps and the …
Bullheading In Drilling Oil & Gas Wells Full Guide
Bullheading is a technique that may be used in certain circumstances during drilling operations to pump an influx back into the formation. In other words, it is a term to denote pumping into a closed-in well without returns. A major concern with this technique is that it may result in fracturing any exposed formation. Bullheading …
Trip Tank in Drilling Applications & Tips
We usually use a calibrated trip tank in drilling to measure mud volumes accurately and change mud volumes while tripping. It must be available on all rigs & must have a level indicator easily readable from the driller’s position. Such an indicator must be accurate to within one-half barrel volume. It is unsafe to trip …
Flow Check | What, When, How-To & Recommendations
Unexplained changes in the readings on the Flow Show and PVT recorders should be investigated promptly. This usually takes the form of a flow check. In other words, They are implemented to guarantee that the well is stable. it should be carried out with the mud pumps off to check the well with Drilling ECD …
Choke Manifold Full Guide & IADC Recommendations
The choke manifold is an arrangement of valves, fittings, lines, and chokes that provide several flow routes to control the flow of mud, gas, and oil from the annulus during a kick ( Kick warning signs – Causes of kick in drilling). Here you shall learn choke manifold parts, function & IADC recommendations in drilling. …
Inside BOP (IBOP), Kelly Valves Full Guide
The Inside BOP (IBOP) as gray valve is a back-pressure type valve (or float valve) that allows stripping operation using drilling kelly / top drive or running drill pipe into the hole without mudflow upward through the valve. It can be stabbed and made up on the drill pipe only at very low flow rates. …
Annular BOP Preventer | Hydril, Shaffer & Cameron Guide
The annular preventer (also called bag type, spherical, or universal preventer) is the most versatile piece of equipment on the BOP stack since it can close around the casing, drill pipe, drill collars, wireline, and even close an open hole. The rubber packing elements of the annular preventers, which allow this flexibility, are also subject …
MAASP In Drilling Definition, Calculations
During well control operations, the maximum allowable borehole fluid pressure at the casing shoe is normally considered to be the critical factor, based on the assumption that the weakest formation is at the shoe. For practical purposes, the corresponding pressure at the surface (Drilling MAASP or Maximum allowable annular surface pressure) is calculated through specific …
Slow Circulation Rate Definition & Application
Well control operations are performed at reduced pump speeds or slow circulation rate in order to: Operation of the pump at a pressure too close to the setting of its relief valve is dangerous. If the relief valve opens, drilling fluid will flow back through the drill pipe and standpipe manifold. Circulation pressures at the …
Choke Line Friction Loss Problem & Mitigation Methods
In subsea situations, a pressure loss exists when circulating through the choke line due to the friction losses in the extended choke line running up from the BOP. This pressure loss is not accounted for in normal Slow Circulating Rate (SCR) measurements, which are taken while circulating up the marine riser (see Fig 1). In …
Rotating Head In Drilling Oil & Gas Wells
Conventionally, one will drill a well and use heavy drilling fluids to control the well pressures and to control the flow of cuttings from the well. Sometimes, using air or gas as the circulating medium or using light mud to drill in an underbalanced condition is beneficial. You must use a rotating drilling head when …
Kick Tolerance Calculation, Definition & Formula
The kick tolerance can be defined as the maximum volume of kick influx that can be safely shut in and circulated out of the well without breaking down the formation at the open hole weak point. Here In this article, we will explain kick tolerance calculations methods, formulas & the most important considerations. Kick tolerance …
BOP & Well Control Drills Procedure For Rig Crew
The purpose of these BOP & Well Control drills procedures or exercises is to familiarize rig personnel with the various equipment and with the techniques that will be employed in the event of a Well Kick. Here, we explain all well control drills including trip drill procedure, pit drill in drilling, H2S drill, Emergency drills, …
Shaffer BOP Features, Mechanism & Manuals PDF
NOV Shaffer Blowout Preventers BOP stack field proved its efficiency in performing good isolation around the drill pipe, across the open hole, and for performing shearing on the drill string. Here you will be able to understand Shaffer BOP ram and annular preventer type components and function. Also, you can download Shaffer BOP manuals & …
Cameron U II Blowout Preventer Features
The Cameron U II BOP takes all of the features of the U blowout preventer and adapts them for subsea use in the 18-3/4-10,000 and 15,000 psi WP sizes. Like all other Cameron preventers, the preventer rams in the U II BOP are pressure-energized. Wellbore pressure acts on the rams to increase the sealing force …
Cameron U BOP Types & Components
The Cameron U BOP blowout preventers are the most widely used ram-type BOP for land, platform (platform rigs) and subsea applications worldwide and offers the widest range of sizes of any Cameron ram-type BOP. Like all other Cameron preventers, the rams in the U BOP are pressure-energized. Wellbore pressure acts on the rams to increase …
BOP Stack Components & Types
Blowout Preventers (BOP) Stack is one of the rig components used to seal the wellbore and thereby contain a kick ( check drilling kick). Two main types of BOP preventers are used in the industry (both types are discussed below). This article will discuss its BOP blowout preventers stack classification, components & types. API Classification …
IWCF WELL CONTROL – PRINCIPLES AND PROCEDURES
1) FUNDAMENTAL PRINCIPLES OF WELL CONTROL 2) INTRODUCTION TO KICKS WHILE DRILLING WELLS 3) KICK INDICATORS OBJECTIVES The objectives of this section are to review the indication of a kick. Early warning signs will be covered as well as positive kick signs. 4) IWCF- SHUT IN PROCEDURES ON A FIXED RIG 5) METHODS OF WELL …
Stripping Operation In Oil & Gas Well Control
Application During operations on drilling or producing well, a sequence of events may require tubing, casing, or drill pipe to be run or pulled while annular pressure is contained by blowout preventers; such practice is called “stripping operation”. Stripping is normally considered an emergency procedure to maintain well control; however, plans for certain drilling, completion, …
Well Control Methods In Oil & Gas Guide
To cover the methods of well control for fixed rigs, cover the special considerations for subsea rigs (Types of drilling rigs), and look at step-down graphs for deviated and horizontal wells. General Well Control Methods The objective of the various kill methods is to circulate out any invading fluid and circulate a satisfactory weight of …
Volumetric Well Control Method For Gas Kicks
The volumetric method is mostly used in workover and production well control operations. It allows the gas to migrate (gas kick behavior) to the surface under control. The gas needs to migrate at over (approx.) 1000′ per hour. To allow the bubble to expand the casing pressure is held constant for a given volume of …
Wait And Weight Method For Killing Operations
What Is the Wait & Weight Killing Method? The Wait and Weight are sometimes called the Engineers or One Circulation Method. At least, in theory, it kills the well in one circulation. Once the well is shut in (hard shut-in well procedure – Soft shut-in procedure) and pressures are stabilized, the shut-in drill pipe pressure …
Driller’s Method Procedures & Calculations
In Driller’s Method, the Kill is split into two circulations to fully control the well. Advantages Driller’s Method In Well Control Disadvantages Applications This method is mostly used on small land rigs where the Driller (check also: driller job description) may have little help and limited equipment. It is also used on highly deviated and …
Kill Mud Weight Calculations In Oil & Gas
Kill Mud is the drilling fluid with a specific weight that will restore the primary well control and will secure the well on its own without the need of closing the BOP stack or any secondary well control. Balance of Pressures Once the well is shut-in providing nothing has broken down, the pressures in the …
Shut In Procedures For Oil & Gas Well Control
Our objective is to cover the shut-in procedures for a surface BOP Stack in case of well control issues & to cover A.P.I. recommendations for these procedures, which include advantages and disadvantages. When any positive indications of a kick (also check: Kick warning signs) are observed and a check shows that the well is flowing, …
Diverter Drilling System For Well Control Full Guide
The function of a diverter system in oil and gas rigs (Check also types of drilling rigs) is to provide a low-pressure well flow control system to direct controlled or uncontrolled wellbore fluids or gas away from the immediate drilling area for the safety of personnel and equipment involved in the drilling operation. The diverter …
Hard Shut In Procedure & Lineup In Well Control
For a hard shut-in lineup, the choke remains closed at all times other than during a well control operation. The choke line valves are aligned such that a flow path is open to the choking system with the exception of the choke itself and one choke line valve located near the blow-out preventer BOP stack. …
Soft Shut In Procedure On Fixed & Floating Rigs
Soft Shut-in Drilling Definition & Lineup Soft shut-in is one of the procedures of closing wells after it gains a kick to its wellbore. For a soft close-in, a choke is left open at all times other than during a well control operation. The choke line valves are aligned such that a flow path is …
Gas Kick Behaviour, Migration & Expansion
In well control, the gas kick is simply to be detected once enter wellbore in water base mud as once driller (driller job description) shut in the well, the SICP & SIDP start to increase slowly with the same values due to gas migration. Of course, it may be difficult to notice such migration in …
Kick Warning Signs, Positive Indicators & 1st Action
The alertness in determining Kick early warning signs in well control is of the uppermost importance to wellbore safety. Careful observance and positive reaction to these signs will keep the well under control and prevent the occurrence of a good flow situation. This article will also discuss the positive indicators for oil well kicks. The …
Well Kicks Guide While Drilling Oil & Gas Wells
1) OBJECTIVES The objectives of this section are to Highlight the Causes of Kicks and Influxes. 2) INTRODUCTION Primary control is defined as using the drilling fluid to control formation fluid pressure. The drilling fluid has to have a density that will provide sufficient pressure to overbalance pore pressure. If this overbalance is lost, even …
Causes of Kick in Drilling | Major 7 factors
When a well gains a kick, it is a big loss as the drilling supervisor and crew had to waste a lot of time trying to kick it out from the well. In this article, we shall learn the major seven causes for kick-in drilling oil and gas wells. As you get to this page, …
Primary Well Control & Kick Prevention In Drilling Tips
To ensure primary well control is in place & prevention of kicks in drilling, the following procedures and precautions must be observed: The Primary Well Control: Mud Weight Mud into and out of the well must be weighted to ensure the correct weight is being maintained to control the well. This task is normally carried …
Fundamental Principles Of IWCF Well Control
Objective The objectives of this section are to introduce the Fundamental Principles of Well Control. General Information The function of Well Control can be conveniently subdivided into three main categories, namely PRIMARY WELL CONTROL, SECONDARY WELL CONTROL, and TERTIARY WELL CONTROL. These categories are briefly described in the following paragraphs. Primary Well Control It is …
Leak Off Test Procedures & Calculations Sheet
Before starting leak off test drilling procedures, gauges should be checked for accuracy. Also, the upper-pressure limit should be determined. It is so simple to run leak off test drilling but if you exceeded certain pressure, you may break the formation and a loss of circulation may occur. Leak Off Test Best Practice Pre-job Procedures. …
