Post on 18-Dec-2015
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NUEVAS TECNOLOGIAS PARA LA CEMENTACIN DE POZOS PETROLEROS
Que es nuevo en Cementacin?Se ha estado avanzando en...Sistemas de Cementos LigerosNuevos aditivos para Cemento y espaciadoresAutomatizacin de los equipos.Simuladores de Tiempo realTratamientos para estabilizacin de pozos y perdidas de circulacin.Registros para la evaluacin de un cementoConceptos relacionados a la migracin de gas.
TEMAS A DISCUTIRRe-descubrimiento del cemento espumado.Solucin para las perdidas de circulacin.Nuevas consideraciones para disear espaciadores.
Redescubriendo el Cemento espumadoEn los aos 80 se lanz el cemento espumado pero su aplicacin perdi fuerza por su dificultad operacional aplicando la tecnologa del momento.
Que es un Cemento espumado?Es un sistema conformado por una lechada de Cemento base, surfactante espumante, y un gas (usualmente Nitrgeno).
Cemento EspumadoGenerador de EspumaGas NitrgenoLechada de Cemento BaseDescarga de Cemento Espumado
Buscamos una espuma estableMantenga sus burbujas separadasSea porosa pero no permeableSu gas no migre formando canalesMantenga la densidad deseada
Beneficios conocidos de los cementos espumadosPodamos llegar a bajas densidadesAlta resistencia segn su densidadEs una solucin Econmica Cementar en una etapaMantener topes de cemento despus de cementarEvitar sellar las fracturas naturalesFacilitaba hacer forzamientos de cemento frente a formaciones dbiles
Dificultades conocidas de los cementos espumadosDificultad operativa para mantener la relacin deseada de Cemento/nitrgeno/espumanteEra casi imposible realizar trabajos para obtener una columna de cemento con densidad constanteNo haba verdadera tecnologa de registros para evaluar estos cementos
Nuevos beneficios de un cemento espumadoDescubrimos.DctilAislamiento de calorEstable a altas temperaturasBuena remocin de lodo.Previene la migracin de gasSe expande (Comprensible)Automatizando los equipos, se hace operativamente mas factible
Cemento Ultra-Ligero (4-10 ppg)Se ha usado para cementar formaciones con bajos gradientes de fractura previniendo perdidas de circulacin durante y despus de cementar
Excelente relacin densidad-resistenciaResistencias a la compresin (24 horas) Clase HClase AClase A + EconolitePSI12.0 11.4 12.011.5 11.5 89o 90o 90o 71o 60o Clase H + EconoliteClase H + WG-17ConvencionalEspumado
Mejor Remocin del lodo
Aumenta la erodabilidad del lodo gelificado o inmvilDisminuye la tendencia a canalizacin.Mejora la capacidad de limpieza del pozoAumenta el contraste reolgico entre lodo/espaciador/cementoAlta Viscosidad
Previene la migracin de GasFlujo a travs de canales irremovidos de lodoFlujo MicroanularPercolacin del gas en cemento sin fraguarTipos de migracin anular de gas
Percolacin del gas en el Cemento sin fraguarSe pierde columna hidrostticaDeshidratacin del cementoPoca Gelificacin del cementoGrandes tiempos entre el estado Liquido y slido
Perdida de presin hidrostticaCementoFluidoCementoGelificandoCementoEndureciendoCemento fraguadoPresin de poro de la formacinPresin desobrebalanceTiempoPresin Hidrosttica
Cemento EspumadoCementoFluidoCementoGelificandoCementoEndureciendoCemento fraguadoPresin HidrostticaPresin desobrebalancePresin de poro de la formacinTiempo
Tiempo de estado plstico9Minutos vs HorasTiempo de Transicin - MinutosTiempo de Transisin - Horas
Flexibilidad del CementoCemento ConvencionalSe presuriz ciclicamente varias veces hasta presentarse una fracturaEl impacto del Caoneo puede fracturar el cemento
El cemento espumado es ms dctilNo se observ fracturas Slo ligera perdida de adherenciaSe presento deformacin sin fracturarse por su naturaleza elstica
Debido a que contiene burbujas de Nitrgeno, el cemento espumado tiene una menor conductividad trmica.El cemento espumado es aislante del calor
Mejor diseo de cementos espumadosEngineering DesignMejor medicin de los parmetros del pozoAditivos mejoradosSimuladores Mejorados
Total Automatizacin e integracin de los equiposUnidad de NitrgenoUnidad de Cementacin Unidad de Inyeccin
Las herramientas ultra-snicas pueden diferenciar el contraste de impedancia de los materiales detrs de la tubera, y a travs de un nuevo software crear imgenes detrs de la tuberaHerramientas avanzadas para evaluacin de el cemento
Limitaciones del Cemento espumadoCoiled Tubing.Poco volumen de cementoPozos sin informacin de caliper (algunos casos)
Perdidas de Circulacin:
Frecuencia de las perdidas deCirculacin5* API Worldwide Cementing Practices, 1st Edition, January 1991RevestimientoPorcentaje de frecuencia por Pozo*USARNAMundialSuperficie242421Intermedio242523Produccin242424Liner182619
Perdidas de Circulacin Las causas para las perdidas de Circulacin son :Fracturas naturales o inducidasFormaciones con espacios vacosFormaciones de alta permeabilidadCanales en zonas dbiles
Perdidas de CirculacinSoluciones comunesMateriales sellantes en el lodoBenGum SqueezeTapones de Cemento + SilicatoRevestimiento.Sus caractersticas son:Requieren varios tratamientosRealizar viajes adicionalesInvolucran tiempo y perdida adicional de lodo (Dinero).
Perdidas de CirculacinUna nueva Solucin Los materiales de FlexPlug son polmeros diseados para reaccionar con cualquier lodo produciendo un material sellante en la cara del pozo o en la entrada de la fractura. La reaccin instantnea permite continuar perforando tan pronto se haya finalizado el tratamiento y no requiere cambios en el ensamblaje de fondo.
Servicio de FlexPlugSM Ventajas sobre los metodos de LCMPuede ser bombeado a travs del BHA presente - Broca y motor, MWD/LWDTrabaja con lodos base agua y aceiteEl sello obtenido no depende de la perdida del fluido Reacciona instantneamenteSe pueden sellar mltiple zonas en un solo tratamiento sin viajes adicionales
8Reaccin del FlexPlug 10 a 60segundos1 horaReaccin BengumServicios de FlexPlugSM
Comparacin de los tiempos de reaccin
Los sistemas Convencionales de LC penetran mas en las fracturasFlexPlugSM sella con poca penetracinTcnicas deLCMTcnicas deLCMFlexPlugPenetracin del tratamiento
FlexPlug lodo base aguaPerfil del productoSe puede preparar con Diesel, Aceites Minerales y/o Sintticos, etc..Reacciona con fluidos base aguaRequiere un espaciador base aceiteSe puede agregar Cemento para mayor resistencia final.
FlexPlug lodo base aceitePerfil del productoSe prepara con aguaReacciona con fluidos base aceiteRequiere un espaciador base agua
January 20, 19979Tcnica de aplicacin
Informacin para el diseo del trabajoTipo de lodoSeveridad del problemaProfundidad de la(s) zona(s) de perdidaGeometra del pozo y la sartaHistoria de tratamientos previos en la zonaDatos de Pruebas de integridad y gradientes de fractura
Volumen del tartamientoRinde el doble !
Chart1
10.242953691912.917159763316.622448979616.782006920418.252028123319.700957934220.879437869820.038049940520.21289062521.359183673522.65625
10.242953691912.917159763318.622448979618.782006920420.252028123321.700957934222.879437869822.038049940522.21289062523.359183673524.65625
10.242953691912.917159763320.622448979620.782006920422.252028123323.700957934224.879437869825.038049940525.21289062526.359183673527.65625
10.242953691912.917159763322.622448979622.782006920425.252028123327.700957934228.879437869830.038049940530.21289062531.359183673532.65625
10.242953691912.917159763324.622448979626.782006920429.252028123331.700957934232.879437869836.038049940536.21289062537.359183673538.65625
10.242953691912.917159763326.622448979628.782006920431.252028123334.700957934237.879437869840.038049940541.21289062542.359183673543.65625
10.242953691912.917159763328.622448979630.782006920433.252028123339.700957934243.879437869847.038049940548.21289062549.359183673550.65625
10.242953691912.917159763330.622448979633.782006920439.252028123345.700957934250.879437869854.038049940555.21289062556.359183673559.65625
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Page &P
5
6.5
7
8.5
10.75
12.25
13
14.5
16
17.5
20
Estimated Rate of Losses, bbl/hr
Additional Final Product, bbls
Recommended Additional Reacted Treatment Volume
Sheet1
Volume of holeAdd'l Vol. forAdd'l Vol. forAdd'l Vol. forAdd'l Vol. forAdd'l Vol. forAdd'l Vol. forAdd'l Vol. forAdd'l Vol. for
per 10 ft of zone10 to 3030 to 6060 to 100100 to 200200 to 300300 to 400400 to 500500 to 1000
0.251010101010101010
0.46.51313131313131313
0.571719212325272931
0.78.51719212327293134
1.110.751820222529313339
1.512.252022242832354046
1.6132123252933384451
2.014.52022253036404754
2.5162022253036414855
3.017.52123263137424956
3.9202325283339445160
&A
Page &P
Sheet1
00000000000
00000000000
00000000000
00000000000
00000000000
00000000000
00000000000
00000000000
&A
Page &P
5
6.5
7
8.5
10.75
12.25
13
14.5
16
17.5
20
Estimated Rate of Losses, bbl/hr
Additional Final Product, bbls
Recommended Additional Reacted Treatment Volume
Sheet2
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Page &P
Sheet3
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Sheet4
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Sheet5
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Sheet6
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Sheet7
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Sheet8
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Sheet9
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Sheet10
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Sheet11
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Sheet12
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Sheet13
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Sheet14
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Sheet15
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Sheet16
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Casos Histricos
FlexPlug SM W Service
Application
Treatment Size
Results
UG Blowout - 30,000 BSW/D
82 bbls
Sealed fluid exit zone
UG Blowout - 1,000 BSW/D + gas
46 bbls *
Sealed influx & exit zone
Lost Circulation - 60 bbl/hr
25 bbls
Squeezed zone to MW + 2 ppg
Lost Circulation - 20 bbl/hr
19 bbls
Refractured zone while POOH
UG Blowout - Rate undetermined
UG Blowout - Rate undetermined
10 bbls
10 bbls
Sealed gas zone
Sealed 2nd gas zone
UG Blowout - Total mud loss
50 bbls
Sealed zone to regain circulation
Lost Circulation - 10 bbl/hr
Lost Circulation - 10 bbl/hr
10 bbls
10 bbls
No squeeze pressure - continued losses
Pumped away - squeezed with cement
Lost Circulation - 20 bbl/hr
Lost Circulation - 10 bbl/hr
25 bbls
25 bbls
Sealed multiple zones - reduced losses
Sealed additional zone & drilled ahead
Lost Circulation - 15 bbl/hr
25 bbls
No squeeze - No cement behind casing
Lost Circulation - 20 bbl/hr
Lost Circulation - 20 bbl/hr
25 bbls
25 bbls
Squeezed zone to MW + 1 ppg
Squeezed 2nd zone to MW + 1 ppg
Casos Histricos
Fallas comunes del tratamientoNo seguir el procedimiento recomendadoInsuficiente volumen bombeadoDesconocimiento del mecanismo de perdida (Formaciones vugulares)Inducir nuevas fracturas al incrementar el peso de lodo equivalente
Consideraciones para disear espaciadores
Tecnologia de espaciadoresLa remocin de lodos ha sido nuevamente evaluada bajo la teoria de ERODABILIDADNuevos espaciadores se han desarrollado con mejores perfiles reolgicosUna nueva tecnologa para medir la humectabilidad del agua dejada por los espaciadores al desplazar lodos base aceite.
Por que naci la Erodabilidad?A menudo las condiciones del pozo no permiten altas tasas de bombeo o flujo turbulentoLas bajas tasas de bombeo no son las mas recomendadas en revestimientos excntricos.La mayora de espaciadores se diseaban bajo reglas empricas (10 minutos de tiempo de contacto o 1,000 ft de espaciamiento)
Propiedades del lodoLavadores/EspaciadoresEjecucin de la operacinCompatibilidad de los fluidosCentralizacinMovimiento de la tuberaFactores que ayudan en la remocin del lodo.
Que es la Erodabilidad?
Viejos Conceptos
Considera un esfuerzo de corte mnimo para erodar el lodo parcialmente gelificado o deshidratado.Los factores presentes son:Velocidad del fluido (Geometra, tasa de bombeo, excentricidad)Reologia de los fluidos (Geles, VP/PC, revoque del lodo, densidad).Esfuerzo de corte del fluido a ErodarConsideraciones de la Erodabilidad
Reducir el esfuerzo de corte del fluido a remover (Dilucin, bajar reologias, tiempo esttico)Mejorar la velocidad de los fluidos (Tasa, centralizacin)Aumentar la reologia del fluido removedor (no siempre buscar turbulencia)Tcnicas para facilitar la Erodabilidad
Calculo de la Erodabilidad
Disear la reologia del espaciador de acuerdo a cada aplicacin (Usando simuladores o modelos de erodabilidad)Preparar un espaciador con caractersticas similares al laboratorio bajo las condiciones de fondoSimplificar el diseo del espaciador segn los requerimientos de erodabilidadUn Nuevo Espaciador (Tuned Spacer)
No exista un mtodo directo para medir la humectabilidad al agua.Los surfactantes y sus concentraciones eran definidos por pruebas de compatibilidadAlgunas veces se usaba mas espaciador del necesario, o no se lograba cambiar a un 100% humectabilidad al agua (Pobre adherencia de cemento y mala interpretacin de registros)Humectabilidad
Anlisis de la Humectabilidad
Chart1
000
0014.2857142857
0025
0033.3333333333
0040
0043.3962264151
0043.8202247191
115044.4444444444
150044.6494464945
165044.8529411765
180045.0549450549
190045.2554744526
197045.4545454545
200046.4285714286
49.1525423729549.1525423729
501250
52.3809523812552.380952381
53.84615384627253.8461538462
54.54545454559554.5454545455
55.22388059712055.223880597
55.882352941213555.8823529412
56.521739130414856.5217391304
56.772334293915256.7723342939
57.142857142915557.1428571429
57.746478873216057.7464788732
58.333333333317558.3333333333
58.563535911618358.5635359116
58.791208791218758.7912087912
59.016393442619059.0163934426
59.239130434819559.2391304348
59.459459459519759.4594594595
59.677419354819959.6774193548
6020060
Spacer #1
Spacer #2
Spacer #3
% Spacer by Total Volume
Meter Reading
11.0 ppg PetroFree Mud
First Instrument
WETR Readings
cc's Spacer% Spacer, bvSpacer #1Spacer #2
00.000
50250
80400
1005000
110551
1206010
12562.518
1306526
1386927
140700
15075280
172862
19597.52
215107.57
22011011
225112.516
23011524
235117.526
24012027
245122.528
Spacer #1: 1.2 GPB each of Cleanbore A, SEM-7, and AS-5.
Spacer #2: 0.6 GPB each of Cleanbore A, SEM-7, and AS-5.
Mud: 13.5 ppg NovaPlus Field Mud
First Instrument
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
100% Water-Wet at 28
Spacer #1
Spacer #2
% Spacer By Volume
Wettability Reading
Wettability Test at Ambient Temperature13.5 ppg NovaPlus Mud
New Instrument-PetroFree
300 cc's of 11 ppg PetroFree Field Mud Mud
Spacer1Spacer2
cc's Spacer% Sp., by Vol.MicroAmpsMicroAmps
0000
5014.300
10025.000
15033.300
20040.000
23043.400
23443.800
24044.41150
24244.61500
24444.91650
24645.11800
24845.31900
25045.51970
26046.42000
29049.25
30050.012
33052.425
35053.872
36054.595
37055.2120
38055.9135
39056.5148
39456.8152
40057.1155
41057.7160
42058.3175
42458.6183
42858.8187
43259.0190
43659.2195
44059.5197
44459.7199
45060.0200
Base Spacer: 13.5 lb/gal Tuned Spacer
Spacer1: 1.2 GPB each of Cleanbore A/SEM-7/AS-5
Spacer2: 0.6GPB each of CleanBore A/SEM-7/AS-5
New Instrument-PetroFree
Spacer #1
Spacer #2
Spacer #3
% Spacer by Total Volume
Meter Reading
11.0 ppg PetroFree Mud
Synthetics
300 cc's of 9.0 ppg NovaPlus (IO) Lab-Prepared Mud
170 F Testing
Tuned Sp.NovaDrilNovaDrilEsterLinear Paraffin
cc's Spacer% Sp., by Vol.MicroAmpsMicroAmpsMicroAmpsMicroAmpsNovaPlusTuned Sp.NovaDril
00.000MicroAmpscc's SpacerMicroAmps
10025.000000
13030.2010100
13430.9024130
14031.8042134
14432.4062140
15033.3095144
15634.20120150
16435.30142156
17036.20150164
17637.00160170
18438.00166176
19239.00170184
20040.00174192
22042.30176200
24044.40182220
25045.500240
26046.4018502500
29049.200187260
30050.002900
32051.610101910300
34053.11819732010
33052.4272710340
34053.1404033027
35053.8575734040
36054.593932002035057
37055.212012036093
38055.915315320062370120
39056.517917987380153
40057.11901900105390179
41057.7195195128400190
42058.3197197410195
43058.919919950176420197
44059.5200200430199
45060.0200135192440200
46060.5200450
47061.0200175196460
48061.5200470
50062.5200197198480
200500
Synthetics
IO
LAO
Ester
L. Paraffin
% Spacer by Volume
MicroAmps
9 lb/gal Synthetic Muds,11 lb/gal Spacer, 170 oF Testing
VersaDrill
% Spacer by Volume
Meter Reading
Nova Dril Wettability
300 cc's of 16.8 ppg VersaDrill Field MudSP1: Laredo, SP2: Alice
170 F Testing
Spacer1Spacer2
cc's Spacer% Sp., by Vol.MicroAmpsMicroAmps
00.000
5014.300
10025.000
12028.600
12629.620
12829.910
13030.233
13230.626
13430.95936
13631.27247
13831.58763
14031.810070
14232.111276
14432.412285
14632.712993
14833.0132104
15033.3136111
15433.9155126
15834.5170137
16034.8175
16235.1177146
16435.3182
16635.6186155
16835.9186
17036.2189163
17436.7169
17837.2195172
18638.3200
18838.5184
20040.0190
21041.2195
22042.3198
23043.4200
Base Spacer: 17 lb/gal Tuned Spacer
Spacer1: 0.4 GPB SEM-7 & Dual A, 0.5 Dual B
Spacer2: 1.2 GPB Musol A, 0.85 GPB SEM-7, 0.2 GPB Dual A, 0.1 GPB Dual B
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
Surfactant 1
Surfactant 2
% Spacer by Total Volume
MicroAmps
16.8 lb/gal VersaDrill, 17 lb/galTuned Spacer - 170 oF
Anlisis de la Humectabilidad
Chart2
0
15
40
125
125
130
130
130
140
140
142
145
146
146
146
148
150
150
148
146
145
145
140
TUNED SPACER
VOLUMEN DE SURFACTANTES
MOJABILIDAD (Hn)
PRUEBA DE MOJABILIDAD
Chart1
0
15
40
125
125
130
130
130
140
140
142
145
146
146
146
148
150
150
148
146
145
145
140
TUNED SPACER
%ESPACIADOR
MOJABILIDAD (Hn)
PRUEBA DE MOJABILIDAD
Sheet1
PRUEBA DE MOJABILIDAD DE LODO
LAS MOROCHAS,REF : WET-00-0008
PARA:ING. PABLO SOLANOCOMPAIA:MOBIL
DE:LABORATORIOPOZO:CEIBA-5X
FECHA:9/10/00
FLUIDOS:DENSIDAD:
LODOLbs/gal
TUNED SPACER11.5Lbs/gal
LECTURAS DE MOJABILIDAD EN AGUA DE LODO BASE ACEITE EN UNIDADES HOGAN Hn PARA
PROPORCION 55:50 DE LODO Y ESPACIADOR, SE FUERON AGREGANDO CANTIDADES IGUALES
DE CLEANBORE A Y CLEAN BORE B HASTA OBTENER UNA MAXIMA MOJABILIDAD
Hogan (Hn)cc cleanboreAcc cleanboreB
011
152220
4033415
12544640
125558125
1306610125
1307712130
1308814130
1409916130
140101018140
142111120140
145121222142
146131324145
146141426146
146151528146
148161630146
150171732148
150181834150
148191936150
146202038148
145212140146
145222242145
140232344145
46140
OBSERVACIONESLa mxima mojabilidad alcanzada fue de 85.7% con 34 cc de Surfactante
(Wettability fue calibrado para obtener un 100% de mojabilidad a 175 Hn)
Nellie RussoKarina Caraballo
AnalistaSuperv de Laboratorio
Sheet1
TUNED SPACER
VOLUMEN DE SURFACTANTES
MOJABILIDAD (Hn)
PRUEBA DE MOJABILIDAD
Sheet2
Sheet3
Permite calentar los fluidosMedida directaSimpleEquipo para medir la Humectabilidad
Foaming significantly increases the viscosity of the base fluid. In general, viscosity increases as foam density decreases (as the nitrogen ratio or foam quality increases).
Foamed fluids (muds, spacers, and preflushes as well as cement slurry) is effective at removing mud and filtercake for several reasons. Firstly, just pumping a viscous fluid past the mud imparts shear or drag energy to mud made less mobile due to static gel strength development, dehydration or being in the small annular volume behind decentralized pipe. In general, thick fluids do not tend to channel through thinner fluids. having the cementing or precement fluids more viscous than mud lessens channeling (mud bypass), further improving mud removal. Foams are to viscous they can lift cuttings often more efficiently even at low pump rates, that normal drilling muds can at high circulation rates. Increased cutting and mud removal equals increased cement coverage.
The increased viscosity of spacers lessens intermising between fluids, minimizing any detrimental chemistry effects that could ensue.
By maintaining stable viscosity and pressure during pumping or even while sitting static (i.e. being thixotropic), water and gas intrusion are minimized or prevented. Again, the net result is a more competent cement sheath and improved zonal isolation.
It's very important to have a foam generator. The Foam Generator is a Tee with a choke nozzle. Typically, we like to see a 500 psi - 1000 psi pressure drop at the choke in order to generate the proper mixing necessary to create a true Cemento Espumado. In order to get the required pressure drop we can vary the choke size depending upon pump rates.A major application of foam cement is a single-stage cement job across weak formations. This is done to prevent lost circulation, save rig time and save money. Foam cement can also be used to squeeze across weak formations. This prevents lost circulation during the squeeze jobs and maintains surface pressure indication throughout the job. Foam cements can also be used for injection conformance or water control treatments.913353535313132The length of time that a slurry begins to develop crystals to the time it possesses compressive strength is the Transition Time. Throughout a slurries transition time, pressure exerted on the zone of interest is decreasing. This allows for the potential influx of fluid or gas. Limiting the transition time of a cement slurry is very critical in the prevention of water and gas flows.Halliburton measures transition time to 500lb / 100 ft2 of slurry gel strength. At 500 lb /100 ft2 of gel strength, the influx of transient fluid or gas migration cannot occur. Flow Stop System I has typical transition times of at or below 30 minutes. At cool temperatures and low cement density this transition time is exceptional when compared to that of typical low density, water expanded slurries. This picture shows the results of a test performed in Duncan on 5 1/2 pipe cemented inside 7 5/8 casing. The inner pipe was pressured in stages until cement failure was indicated at 4500 psi by longitudinal permeability of the cement sheath. When foamed cement was used in the casing annulus and tested in the same way, cycling the internal pressure as high as 10,000 psi caused no radial cracks in the cement sheath. Only a slight amount of debonding was indicated by permeability tests. The foamed cement was able to deform and absorb expansive energy without failure due to its elastic nature.Customized blend is most often is simply neat cement and the surfactants required to keep the foam stable.23On a ZoneSeal job, data is captured and displayed real-time as the job is pumped. This is accomplished by connecting data cables first from the cement unit to the injection skid, then to the nitrogen unit, and finally to a laptop computer. This data acquisition allows the Halliburton certified personnel on location as well as the customer to monitor various properties of the fluids and gases being pumped downhole. For example, we can monitor slurry rate, volume, and pressure, surfactant rate and volume, and nitrogen rate, volume, pressure, and temperature. This data is also captured and saved for later review.
Las perdida de circulacion es un problema que involucra perdida de fluidos del pozo mientras este es perforado o completado.Este problemas, en sus diversas formas, puede demorar las operaciones agregando costos adicionales. En la industria petrolera se han probado y usado diversos tipos de materiales y tecnicas para solventar esta situacion obteniendose diversos niveles de exito.45Esta estadistica nos muestra que tan frecuentes pueden ser las perdidas de circulacion.El servicio de Flexplug es una nueva solucion para controlar las perdidas de circulacion.
Este nuevo servicio de Halliburton ha sido desarrollado como un medio efectivo para controlar las perdidas de circulacion en fracturas naturales o inducidas, formaciones con grandes espacios vacios, con altas permeabilidades y canales en zona de bajos gradientes de fractura,FlexPlug suministra varias ventajas las cuales pueden ayudarlo a solucionar su problema de perdida de circulacion rapida y efectivamente.
FlexPlug ahorra tiempo de taladro...FlexPlug puede ser bombeado a traves del BHA incluyendo broca, motor, MDW y LWD... FlexPlug elimina viajes adicionales necesarios en otros tratamientos de LCM... FlexPlug reacciona instantaneamente. La perforacion puede continuar tan pronto se ha obtenido la presion de Squeeze. No existe Tiempo de espera en un tratamiento de FlexPlug.781110La figura ilustra las diferencias entre otras soluciones para perdidas de circulacion y Flexplug.Los Metodos Convencionales de LCM requieren perdida de fluido a traaves de la cara de la formacion para llenar las fracturas.
FlexPlug W : Es un sistema de Aceite que reacciona con fluidos de perforacion/completacion de base agua o aguas de formacion sin importar su salinidad o pH.
FlexPlug W puede ser preparado con diesel, kerosene, aceites minerales o sinteticos y esteres. En algunos casos se adiciona cemento al sistema con el fin de obtener una mejor resistencia final.FlexPlug OBM : Es un sistema preparado con agua que reacciona con fluidos base aceite (Lodos invertidos base aceite, Lodos sinteticos, etc.).99Procedimiento en un tratamiento de FlexPlug Coloque la sarta arriba de la zona Ladrona (A una distancia igual a dos veces la altura del tratamiento del FlexPlug) Bombear espaciadores compatibles adelante y atras del FlexPlug. Circule el FlexPlug hasta la punta de la sarta. Bombear por lodo por el anular y Flexplug en directa simultaneamente para obtener una mezcla de 50:50 Haga forzamiento de la zona de perdida segun la maxima presion permisibleEsta grafica ayuda a definir los volumenes adicionales de tratamiento que se recomiendan segun la severidad de las perdidas.
Los volumenes para el tratamiento de FlexPlug varian de acuerdo a la severidad del problema. El volumen minimo es el volumen del pozo en el intervalo de perdida de circulacion
Por experiencia se recomienda un volumen absoluto de 10 bbls.
Despues de mezclar el FlexPlug con el lodo, la cantidad final del tratamiento sera aproximadamente el doble del volumen de FlexPlug que fue bombeado.
High-rate, turbulent flow has and always will be the preferred displacement technique. However, drilling conditions often do not afford us this luxury. Low-rate pumping with thin fluids in eccentric annuli is not a preferred cementing technique when the mud is in poor (gelled) condition. The Erodibility Technology was developed to address this concern, and Tuned Spacer was developed to compliment the total package. {This does not mean we recommend Tuned Spacer over other systems (such as water) when such systems are proven for a given situation.}
Before we start, lets take a look at some of the displacement best practices. The practices should include: Mud conditioning, mechanical aids, centralization.[Fluid velocity] Pumping in turbulence is most desirable because of maximum mud removal. However, in some cases, this is not feasible. Therefore, the cement slurry with the best possible rheological properties will be pumped at the highest rate possible. [Spacers and flushes] A good spacer should 1). Adequately separate and be compatible with all well fluids it contacts 2). Remove both mud and filter cake and protect the formations encountered, and 3). Not adversely affect the properties of the cement slurry or the drilling fluid.Model studies reveal that any decrease in viscosity of the drilling fluid increases the displacement efficiency.
Pipe centralization helps create a uniform annular flow area and thereby equalizes the pressure distribution around the pipe. This defines the percent standoff and displacement efficiency. The % standoff tells how well the pipe is centralized and displacement efficiency tells how well the mud is displaced. It is recommended to have at least 70% standoff over the zone of interest. This minimum stress can be obtained from either running the static gel strength test on the mud in the Mini Macs or from running the Erodibilty cell to get the E factor. The current model doesnt take into account the reciprocation and chemical aids added to condition the mud prior to displacement. Therefore, the results obtain will be the worst case scenario since reciprocation and chemical aids will help condition the mud which would lessen the required stress.Put into the Force Model with the measured minimum stress obtained from either the Mini Macs, Macs or the erodibility cell. Also, fill in the known information in the shaded area.Then let the model circulate the mud in the hole and evaluate the ability of the mud to clean itself up. If the mud can circulate the hole clean, then the spacer design will be based upon the YP of the flowing mud. If not, the spacer design will be based upon the minimum shear stress obtained from tests mentioned above. The information of the spacer obtained from the force model will be inputted into a proprietary spreadsheet to give material requirements to mix the desired tuned spacer ( if needed, open the Excel file that contains this Spreadsheet. It is too big to put it in Powerpoint and still can see clearly.)After inputting the required information (shaded boxes), the model will give the flow rates needed to achieved a desired percent displacement efficiency at a given % standoff. Note that these flow rate for each fluid is determined from the required shear stress input in the box on top. If for example, the flow rate of cement is needed to displace the spacer, then the yield point of the spacer should be input as the required shear stress.Our goals were to develop a new spacer system which would allow an easy customization of rheological properties with improved wellbore displacement. The design of the spacer would require the use of the erodibility concept to get maximum benefits.Improve compatibility by lowering system reactivity and use of synergistic components. The use of spreadsheet give a simplified design of spacer based on both the desired YP and density.This graph illustrates when an 11 ppg PetroFree mud inverted to a water-wet condition. The dark blue line represents a 13 ppg Tuned Spacer containing 1.2 gal/bbl each of Cleanbore A, SEM-7, and AS-5. The purple line is the same spacer with only 0.6 gal/bbl of each surfactant.The spacer with 1.2 gal/bbl surfactant loading completely inverted the emulsion after about 45% by volume spacer addition and did so almost instantly. The spacer with 0.6 gal/bbl surfactant loading completely inverted the emulsion after about 60% spacer addition. Current wisdom indicates that the emulsion should probably be inverted between 40-70% spacer addition. Inverting the emulsion sooner can create solids settling problems and inverting later may not allow enough volume to completely leave surfaces water-wet. The meter consists of a customized stainless steel Waring blender jar with an internal heater and thermocouple to allow operation at BHCT. A Eurotherm controller on the left front of the box assures constant temperature control. The meter dial on the right front of the box displays the microamperage conducted across the electrodes. A potentiometer below the dial allows calibration for the various fluids to be tested.
It is relatively compact and easy to transport to remote locations.It is designed to be used in any lab with 110 volt supply (all HES labs have Waring blenders).