Category Archives: Servicio de Pozos
Although not part of subsurface equipment , the Christmas tree is usually the first component encountered by a workover/completion crew. The Christmas tree is a series of valves, flanges, choke body and connectors that allow the controlled flow of produced fluids.
Applications usually dictate what type of Christmas tree will be needed. There are many different designs and complexities of Christmas trees. Simple units, such as a pump jack setup, may consist of a stuffing box with
no valves. Complex tress may have numerous master and wing valves. Factors taken into account in tree design include pressure, surface environment and temperatures, other types of produced fluids, down hole envoronment, fluid temperatures and economics.
The tree should be lubricated on a regular schedule. Good maintenance minimizes complications during production. It also leads to smoother repair and removal.
The basic components of the Christmas tree include the following:
- PRESSURE GAUGE: Pressure gauges allow well pressures to be monitored. Tubing pressure and casing or annular pressures are monitored with these gauges.
- GAUGE FLANGE (CAP): Provides a seal for the top of the tree and has provisions for a pressure gauge. When this flange is removed, it provides access to the tubing.
- CROWN VALVE (SWAB VALVE): The crown valve is used to shut off pressure and allow access to well for wireline, coil tubing, workover, etc, units to be rigged up.
- FLOW TEE (CROSS, TEE): The flow tee is used so that tools may be run into the hole while allowing production to the flow line.
- WING VALVE: A wing valve is used to shut off the well for most routine operations. These are the easiest to replace in case of damage or cutting out of the valve.
- CHOKE: The choke controls the amount of flow desired from the well.
- MASTER VALVES: master valves are the main shut off valves. They are open most vof the well’s life and are used as little as possible, especially the lower master valve.
- TUBING HANGER: A tubing hanger suspends or supports the tubing string, seals off the casing annulus, and allows flow to the Chirstmas tree.
- CASING VALVE: The casing valve gives access to the annulus between tubing and casing.
- CASING HANGER: A slip and seal arrangement that suspends, and seals off, the casing in the casing bowl.
- CASING: Casing is a pipe string that supports the wellbore to prevent it from caving in and prevents communication from one zone to another.
- TUBING: A pipe string that contains and allows the flow of fluid produced by the formation.
During a rig move in and rig up, extremme care must be taken not to damage the tree. Carelessness at this point could prove fatal to rig and/ or personnel.
Downhole video was first used in the Coalinga field in 1998. Since then, video technology has been used extensively to record images of casing damage, liner damage, wellbore plugging, and analysis of remediation procedures. In many cases, downhole video technology has become the logging method of choice due to its unparalleled ability to accurately assess the downhole environment. This said, downhole video technology is not applicable in all cases.
The first attempts to use camera technology in a wellbore occurred in the 1940’s at the request of a local pump manufacturer located in the San Joaquin Valley. The early attempts led to the capture of black and white pictures on stereoscopic slides that were used with a viewfinder to create a 3-D aspect. These early cameras were very large in diameter and limited (downhole video limitations) to depths of up to 1000 feet. Technology led to further developments in downhole video deployment in the 1960’s through development of coaxial cable capable of
handling the transmission of high frequency signals required for motion video. In the early 1990’s, an Electro-Opto logging cable was developed utilizing fiber optic technology1. This greatly enhanced the ability of the camera by addressing pressure constraints and opening up new applications in production logging.
The downhole video camera uses Electro-Opto fiber optic technology. This technology produces real time video at 30 frames per second with a working temperature of 257 F to 350 F, depending on tool diameter. The tool is made up of three basic components – the electrical chassis, the centralizer, and the “Backlight” camera. The light source is positioned above the camera in the same housing. This facilitates indirect illumination, as well as creates an unobstructed view of the wellbore. This coupled with a surfactant applied to the camera lens allows the operator to descend into the well through an
oil/gas column of several thousand feet and maintain the ability to image the wellbore where a clear fluid is the primary medium. This technology is routinely applied to pumping wells with minimal preparation. In many cases, by shutting in the well and allowing the fluids to separate, clear real time video can be achieved.
Today, downhole video technology is a viable diagnostic tool for many downhole applications. Downhole video technology has been used for numerous applications including mechanical inspection, open hole logging, formation damage analysis, fishing operations, as well as detection of fluid and sand entry.
Hola a todos los seguidores de Petroblogger, en este escueto post más que teoría quiero mostrarles en forma gráfica lo que sucede en el funcionamiento de los distintos Sistemas de Gas Lift existentes tanto el Continuo como el Intermitente. Las animaciones son bastante versátiles por lo que rápidamente se puede inferir la forma de funcionamiento de este tipo de Levantamiento Artificial asimilando a la vez la variada teoría que existe al respecto.
Modo de Instalación de una Válvula de Gas Lift
Descarga continua gas lift
Descarga de un pozo operado mediante Gas Lift Intermitente con Controlador
Gas Lift Intermitente con controlador
Descarga de un pozo produciendo mediante Gas Lift Intermitente sin Controlador
Gas Lift intermitente sin controlador
Que sucede cuando hay un orificio en la tuberia de produccion de Gas Lift
Orificio en tuberia de Gas Lift
Modo de operación de una Válvula de Gas Lift Continuo
Forma de operación de una Válvula de Gas Lift Intermitente
The general purpose of Production Logging is to evaluate the behavior, and type, of fluids within the wellbore during either production or injection operations. Although there are a number of logging services available to the industry which provide this type of information, a standard group of production logging tools will include a spinner flowmeter device, fluid identification tools, borehole pressure and temperature measurements, along with natural gamma ray and casing collar locators. These logging tools should be combined into one tool string in order to provide simultaneous measurements, thus ensuring that all measurements are made under like conditions.
Objectives of Production Logging
There are objectives associated with production logging of which one primary function is to evaluate the flow of fluid both in the wellbore and outside the pipe. As in most logging applications, we measure certain physical properties and then use interpretation techniques to determine reservoir characteristics and extent of mechanical problems.
Objectives of production logs can be grouped into three broad classifications:
- To monitor reservoir performance efficiency throughout the life of a well.
- To define completion problems which are detrimental to maximum well performance.
- To gauge treatment effectiveness by injection/production profiles.
Figura. Production Logging Curves
Applications of Production Logging
There are many applications in both open hole and cased hole environments. Openhole applications can include locating loss of circulation zones and underground blowouts. Besides flow profiling in cased holes, other uses include locating top of cement, evaluating gravel pack quality, location of perforations, effectiveness of well treatments, and numerous others.
When performing injectivity test, production logs are used to determine where and what percentage of the injected fluid is displaced in the wellbore. This can help determine permeability comparisons, plugged perforations, and the locations of leaks in the casing/tubing and/or plugs and packers.
Production logging measurements usually consist of several types of logs, including temperature, fluid density, fluid capacitance, pressure, and spinner-flowmeter, along with standard casing collar locators and gamma ray logs. The type of flow regime and number of fluid phases will determine whether all of these are indeed necessary. These measurements are usually made in a single logging run for two primary reasons:
(1) to reduce rig time, and
(2) to make all measurements under the same wellbore conditions.
Multiple passes, both up and down, should be logged at different cable speeds to ensure correct spinner-flowmeter operations and eliminate any well instability effects.
- Geometrical Perforating
- Before firing, during penetration
- Clean perforation, Dirty perforation
- Effect of damaged zone thickness on productivity radio
- Effect of perforation diameter on prooductivity radio
- Effect of crushed zone permeability on productivity radio
- Effect of shot density on productivity radio
- Effect of gun phasing on productivity radio
- Channel behind the casing on primary job