Control de Error de Herramientas para el posicionamiento de pozo Control de Error de Herramientas para el posicionamiento de pozo. Prácticas de registro para disminuir los errores gruesos. Presentation based on 2 spe papers Joint work by Gyrodata, Statoil & Inteq Work QC through ISCWSA Papers are now merge into one, which have been reviewed & accepted for publication in “SPE drilling & completion”  Spe’s experts recommend the proposed QC policy Autores: Roger Ekseth / Eduardo Ruiz Presentado en: Jornadas de Perforación, Terminación, Reparación y Servicio de Pozos. "Ing. Héctor Giordano“ Interpretación personal de los Trabajos del SPE 103734 y 105558

Para que tomar un registro direccional? Directional drilling can for ease by compared with driving a car in an unknown area The goal is in both cases to hit a target you don’t see at the beginning

Para que tomar un registro direccional? The underlying reason may be different Directional drilling is usually driven by a wish to earn money While driving in a virgin area might be driven of other personal interests for example meeting someone new….

Para que tomar un registro direccional? But in both cases, You don’t want to end up in a dead end This can remove your profit Or make somebody unhappy

Utilización de los registros direccionales The fact that we don’t see the target from the origin makes it necessary with some aiding tools: Driving instructions Drilling / survey program

Utilización de los registros direccionales MWD But that is not enough We need to verify that we are following the instructions Easy when we are driving We may use our eyes to read road signs But we can’t use our eyes in directional drilling They don’t work downhole We need artificial eyes – the MWD

Utilización de los registros direccionales MWD Gyro But it might still be difficult to reach the target The road signs might be missing or misleading It is then nice to have access to additional aids like a GPS Similar, the MWD is not always seeing everything, and sometimes even not the correct thing A gyro is in many ways complimentary to the MWD, And can be looked upon as the directional driller’s GPS

Utilización de los registros direccionales MWD Gyro But road signs and GPS are not giving you any guarantee for reaching the target You may still run into a dead end if you ignoring the traffic regulations Similar, the MWD and Gyro might bring you outside the target if you don’t utilize an adequate QC

SEGURIDAD But loosing your target is not the only negative outcome if you ignore the traffic regulations The risk for ending up in a fatal accident is also higher than normal And ignoring survey QC might result in much more severe results than dry holes

SEGURIDAD This is events we don’t want to happen, It is necessary to take active measures to avoid them This will of course cost money The problem is to find the correct balance between safety and productivity

Seguridad Cinturón de Seguridad MWD QC-test Rotación Shot, Etc. Air bag Registros de Verificación Frenos ABS Medidas de verificación de profundidad Active use of car safety equipment is an alternative that can be used to Seat belt is a typical example of a safety installation that will reduce consequences of unacceptable evens like a car crash But it has to be used MWD QC-tests, rotation shot tests, etc can be looked upon as the seat belt in the directional drilling world Air bag is an additional safety device that further reduces consequences when used together with seat belts and verification surveys are the air bags in the directional surveying ABS brakes are a third example of a common safety device which in our industry has its counter partner verification depth measurements

Las Recomendaciones o requerimientos varían con el tiempo People take nowadays seat belts and air bags for granted Nobody will consider buying a new car without But it has not been like that forever

Las Recomendaciones o requerimientos varían con el tiempo A Swedish engineer at Volvo took patent on seat belts as late as 1959 So buying a car with or without a safety belt did not become a problem it is necessary to consider before after 1959

Las Recomendaciones o requerimientos varían con el tiempo An almost similar history can e give for the air bag It was in the beginning a high cost device in only a few luxury cars And only available for the driver It became then available also for the front passenger seat And is today present both in the front and sides of almost all new cars Our requirements for car safety devices is therefore something that vary with time. It is dependent on the current knowledge on the problem at that time And n recommendations we then are given The same can be said about directional surveying Some one will get new knowledge today And this might necessitate an adjustment of current practices

Fundamentos en la incertidumbre del posicionamiento de pozo Los modelos de incertidumbre nos proveen de un método para determinar cuán lejos podemos estar de un objetivo cuando hacemos una estimación Other vice is the real uncertainty large - The orange ellipsis The problem is , however, that we have no clue about the size of the orange ellipsis But the weaker the QC is, the larger is probably the orange ellipsis It will in the following slides be shown what is needed to fulfill the requirements stated here And thereby return to a world where the purple ellipse of uncertainty is valid To a world where we can trust our safety judgments

Fundamentos en la incertidumbre del posicionamiento de pozo La incertidumbre de la posición del pozo basado en los modelos de error son solo validas si los registros son libres de errores gruesos. Ver trabajos SPE-67616 y SPE-90408 Sin un control de calidad adecuado no se puede asegurar que los datos están libres de errores gruesos Verificar todas las fuentes relevantes de errores Realizar toda la documentación necesaria SPE 67616 = MWD error model paper SPE 90408 = Gyro error model paper  Ellipsis of uncertainty (purple) is only valid when both point are fully satisfed

Fundamentos en la incertidumbre del posicionamiento de pozo La incertidumbre de la posición del pozo basado en los modelos de error son solo validas si los registros son libres de errores gruesos. Ver trabajos SPE-67616 y SPE-90408 Sin un control de calidad adecuado no se puede asegurar que los datos están libres de errores gruesos Verificar todas las fuentes relevantes de errores Realizar toda la documentación necesaria Other vice is the real uncertainty large - The orange ellipsis The problem is , however, that we have no clue about the size of the orange ellipsis But the weaker the QC is, the larger is probably the orange ellipsis It will in the following slides be shown what is needed to fulfill the requirements stated here And thereby return to a world where the purple ellipse of uncertainty is valid To a world where we can trust our safety judgments

Estado actual de los modelamientos de error y controles de calidad Las practicas de control de calidad de registros no están estandarizadas y varían mucho No se entiende ampliamente la importancia de los controles de calidad adecuados El uso de modelos de errores sin el control de calidad apropiado es una solución incompleta. Se necesitan tomar medidas de control de calidad asociadas directamente al modelo de error. But first A brief summary of how the author group consider the current status Within the directional surveying. ::::: ::::: Use slide text This list show that it is a lot of room for improvements A lot of actors are driving cars without ABS breaks and air bags Even to drive without seat belts seem to be quite comon

Test de control de Calidad Verificaciones Internas Basados en los datos del fondo de pozo tomados de una sola estación o de un registro completo Verificaciones externas Basados en datos externos o de registros superpuestos Se necesitan los dos tipos de controles Verificaciones internas mientras se perfora Las verificaciones internas no son suficientes para un control de calidad completo del registro The two QC papers presents a number of QC tests Some of them are new, while others are adjusted versions of pre known tests Both are, however, linked directly to the error model A feature that has not been available in the passed The different tests will not be given here, but are described in the two papers The tests can be divided into two groups ::::: ::::: Use slide text

Verificaciones internas Test de la referencia usada en la medicion Pueden ser simples o multi estación Test del GTotal Verifica la performance de los Acelerómetros Test del campo magnético Verifica la performance de los magnetómetros. Test del campo de rotación terrestre Verifica la performance del gyro ::::: ::::: Use slide text

Test adicionales en la misma profundidad Test de QC Internos Test adicionales en la misma profundidad Posibilidad de hacerlos mientras se perfora Mediciones repetidas Sensores adicionales Test de desalineación con registros de rotación Componentes de desalineación de las herramientas dentro del BHA Test de diferencias con dobles profundidades Agrupa los errores de diferencias debido a la profundidad Para registros con cable que se corren en barras o casing usando CCL. ::::: ::::: Use slide text

Test de control de calidad Externos Test de entrada/salida Verificación de las derivas de los gyros continuos Test de desalineación Test de registros de verificación Test de diferencias de Inclinación Test de diferencias de Azimut Test de diferencias de Coordenadas ::::: ::::: Use slide text

Test de control de calidad Externos ::::: ::::: Use slide text

Test de control de calidad Externos ::::: ::::: Use slide text

Niveles de Control Controles de Calidad Combinados We shall now look at which error sources that are controlled through the different QC tests The QC level will be shown in a traffic light format Red = No control  Stop, this is dangerous Yellow = Some control  Be careful , trouble might arise Green = Good control  Continue, you are safe We will start with MWD Not because is the “bad boy”, but because it is so common and trusted

MWD (Incl. IFR) Terminos de Error Single - Shot Accelerometer errors Magnetometer errors Misalignments Sag error Magnetic reference errors Declination error Depth errors The different error sources are in this table lumped together in related groups Accelerometer-, misalignment-, and sag- errors affect he inclination Magnetometer-, misalignments-, magnetic reference- and declination- errors affect the azimuth And depth errors affect of course the measured depth To trust a single MWD station, even when all available single station tests are applied, is according to this table a risky sport Neither the inclination, the azimuth or the measured depth can be guaranteed free from gross errors The use of In-Field Referencing does not change this picture at all There will still be present red boxes for all three measurements Sin control Algun control Buen control

MWD (Incl. IFR) Error Terms Single - Shot Multi Stat. Cor. Accelerometer errors Magnetometer errors Misalignments Sag error Magnetic reference errors Declination error Depth errors Multi station tests might be run when a number of consecutive stations have been collected This improve on the over all QC situation, But we are far from covered There is still a large number of red boxes And multi station tests have their limitations They can only be used for one survey section (bit run) a time They can give false results in tangent sections and when bent subs are used no control Algun control Buen control

MWD (Incl. IFR) Error Terms Single - Shot Multi Stat. Cor. Rot. Accelerometer errors Magnetometer errors Misalignments Sag error Magnetic reference errors Declination error Depth errors Adding one or more rotation shot per section increases the reliability But does not close the QC gap Sin control Algun control Buen control

MWD (Incl. IFR) Terminos de Error Single - Shot Multi Stat. Cor. Rot. Out Errores de Accelerometros Errores de Magnetometros Desalineacion Error de Sag Errores de referencia Magnetica Error de declinacion Errores de profundidad The same is the case if we run in-run / outrun test, - The last available group of internal tests We do still have 3 red boxes The sag error is red  The inclination may be wrong without our knowledge The declination error  The azimuth may be wrong The depth errors Directional drilling based on only MWD without any external verification is therefore the same as running a car without seat belts, airbag and ABS brakes You may get away with it. Not only once, but many times The likelihood for a disaster is, however, present, and you will sooner or later pick the wrong card, And this might be already tomorrow Sin control Algun control Buen control

GWD Terminos de Errores Single - Shot Multi Stat. Cor. Rot. - Shot In / Out Errores de Acelerometros Errores de Gyro Desalineacion Error de Sag Errores de profundidad GWD is a bit better of - At least if all possible internal tests are run The azimuth can be fully QCed through its own measurements And to some degree also the depth But not the inclination, which is dependent on external verification For a GWD single shot is, however, the situation just as weak as for MWD Sin control Algun control Buen control

Comparacion de Gyros Drop Terminos de Error Single - Shot Multi Stat. Cor. Rot. - Shot Errores de Accelerometros Errores de Gyro Desalinealidad Error de SAG Errores de Profundidad MWD and GWD are the only real time survey alternatives Other survey methods can only be run after the well or parts of the well has been drilled A gyro-compassing drop survey is one example of this type of survey The table shows that nether a drop survey is sufficient to satisfy the QC requirements by itself Sin control Algun control Buen control

Gyro-Compas Con Cable Terminos de Error Single - Shot Multi Stat. Cor. CCL Errores de Acelerometros Errores de Gyro Desalinealidades Errores de Profundidad The same is the case for a wireline based gyro-compassing survey Even if it is run with a CCL Sin control Algun control Buen control

Gyro Continuo Terminos de Error Basic AI + CDC AI + CDC + CCL Errores de Initializacion Errores de deriva Desalineacion Errores de profundidad A continuous gyro survey based on both in-run and outrun data and CCL Is the only stand alone survey method with satisfactory internal QC The survey has to be run on running gears that allows tool rotations So advanced initialization (AI) And continuous drift corrections (CDC) can be run A single in-run or outrun basic continuous survey does on the other hand not have a proper QC Sin control Algun control Buen control

MWD + Gyro Terminos de Error MWD + Drop MS Cont. Errores de Acelerometros Errores de Magnetometros Errores de Gyro (GC, Init., Deriva) Desalineacion Error de SAG Errores Magneticos (Ref., Dec.) Errores de Profundidad Both MWD and GWD are according to what has been shown earlier dependent of verification surveys to justify the use of the error model A verification survey can be a full survey, parts of a survey or just a single shot with an other survey tool This table shows the combined QC level for MWD surveys verified by different gyro surveys A MWD/drop combination is only controlling the azimuth While both wireline and CCL based multi shot surveys and continuous surveys are controlling all 3 They are the seat belts, the air bags and the ABS brakes In the directional surveying world Sin control Algun control Buen control

Programas de registros mínimos recomendados Seat belts, air bags and ABS brakes is not enough to ensure safe driving The safety equipment has to be maintained and used Similar in our industry e

Programa de control de calidad mínimo recomendado en un registro direccional Después de cada estación G-total-, B-total/dip- test No se pueden controlar Desalineación, Declinación, Sag y profundidad Tomar por lo menos uno por sección Test de rotación Hay algún control de des alinealidad Al final de cada sección de registro Corrección Multi estación La validez de msc depende de la geometría del pozo Se mejora la precisión aunque no se pueden controlar mas términos de error. En una carrera intermedia de trepano Registros de verificación independientes EMS - No se controla la Declinación Drop gyro - No se controla los errores de profundidad Wire-line gyro - Se pueden controlar todos los términos de error Es necesario un registro definitivo a la profundidad final Registro de gyro continuo Inicialización independiente Son necesarias ambas carreras de entrada y salida ::::: ::::: Use slide text

Conclusiones Tanto los controles de calidad interno como externos son necesarios para justificar el modelo de error. Los controles de calidad internos protegen de varias fuentes de error y deben usarse siempre Los controles internos no pueden detectar errores de des alinealidad, SAG y declinación. La técnica de Multi-station es una de la mas poderosa técnica de control de calidad interno pero no siempre se puede usar. Los controles de calidad basados en tomas simples con rotación en la misma profundidad son muy débiles pero a menudo la única alternativa. Las verificaciones internas deben ser suplementadas con datos tomados con fuentes externas. Los registros de verificación independientes de Inc., As y coordenadas es la herramienta mas efectiva para detectar errores gruesos. Conclusions from SPE-103734 and 105558 ::::: ::::: Use slide text Following these recommendations means that we can get rid of the orange ellipsis of uncertainty

Conclusiones Tanto los controles de calidad interno como externos son necesarios para justificar el modelo de error. Los controles de calidad internos protegen de varias fuentes de error y deben usarse siempre Los controles internos no pueden detectar errores de des alinealidad, SAG y declinación. La técnica de Multi-station es una de la mas poderosa técnica de control de calidad interno pero no siempre se puede usar. Los controles de calidad basados en tomas simples con rotación en la misma profundidad son muy débiles pero a menudo la única alternativa. Las verificaciones internas deben ser suplementadas con datos tomados con fuentes externas. Los registros de verificación independientes de Inc, Az y coordenadas es la herramienta mas efectiva para detectar errores gruesos And return back to the purple one Which means that we have reestablished control with our drilling project We know how much uncertainty we have in our wellbore positions And can use this information actively to ensure “safe driving” during the entire drilling process, And later in eventually future relief well drillings

No QC = No Safety Belts No Verificación = No Airbag It is important to remember that: MWD or GWD without internal QC is equivalent with not using the seat belts MWD or GWD without verification surveys is equivalent with broken air bags It can lead to a disaster - not necessarily today or tomorrow, but sometimes in the future We don’t want to be responsible for for example an exploding platform We want the platform to remain as a nice picture motive also when the drilling has been completed

Las buenas practicas pueden cambiar con el tiempo An finally Don’t forget that what you today consider as a good practices Tomorrow might become a bad practices No one considered in the past a remote volcano eruption as an important check point in their personal travel QC Everybody know now that this is a factor that can give you a vey unpleasant experience if you are not prepared Well, this presentation should hopefully have a similar effect. Ignoring its recommendations might lead to unpleasant experiences in the future