Changes in Annulus Pressure, Increase Oil Production

March 2016

OBJECTIVE

• Show : lab test performed , field experiences for improving production , with an equipment which has an expert system and control valve that automatically control the annular fluid level, obtaining an optimal point.

SAN CRISTOBAL FIELD, LOCATION PETROLERA INDOVENEZOLAANA

Prod. Acumulada petróleo (Nov. 2015): 111,3 MMBN

Prod. Acumulada gas (Nov. 2015): 42,6 MMMPCN

Pozos activos (Nov. 2015): 109

Pozos inactivos (Nov. 2015): 22

Pozos de disposición de agua: 03

Res. Rem. de petróleo (Nov. 2015): 255,7 MMBN

Res. Rem. de gas (Nov. 2015): 52,7 MMMPCN

Unidad productora principal FM. OFICINA

N° de yacimientos oficiales: 4

Profundidad promedio: 2700 pies

Rango de gravedad: 14-18 ° APIProducción actual: 24,6 MBND

Método de producción: BCP

N° de estaciones de flujo: 2

Superficie: 160,18 Km²

SAN CRISTOBAL

GENERAL DATA INDOVENEZOLANA, RESERVOIR PARAMETERS

RESERVOIR OFIH SCR 2, WELL NZZ-196

Pi: 1287 lpcPb. 1090 lpcPactual: 950 LpcTy= 156 °F °API: 16,1Viscosidad: 14,4 cpN° pozos: 19

Introduction

Over 70 equipment of automatic casing control valve have been installed in Venezuela since 1998, with a successful rate around 50% in which incremental production over 10 % have been attained

NUMBER EQUIPMENT WELL YEAR BOPD (BEF.) BBOPD (AFT) ORIGIN1 MAXIPROD UM-113 1998 118 187 WATER CUT REDUCTION2 UM-78 1998 546 872 WATER CUT REDUCTION3 UM-105 1998 288 540 WATER CUT REDUCTION4 UM-114 1998 154 173 WATER CUT REDUCTION5 GG-185 2001-2002 33 263 WATER CUT REDUCTION6 MFB-440 2001-2002 142 400 WATER CUT REDUCTION7 MFB-584 2001-2002 63 960 WATER CUT REDUCTION8 MFB-432 2001-2002 384 1094 WATER CUT REDUCTION9 MFB-595 2001-2002 29 238 WATER CUT REDUCTION

10 JOC-605 2004 190 570 WATER CUT REDUCTION11 MOT-35 2006 1326 2518 WATER CUT REDUCTION12 MOT-58 2006 608 896 WATER CUT REDUCTION13 MOT-59 2006 787 1100 WATER CUT REDUCTION14 LS-2880 2012 67 168 WATER CUT REDUCTION15 LS-2200 2012 98 187 WATER CUT REDUCTION16 SIAP MFB-386 2005-2006 131 170 PUMP EFFICIENCY/GAS 17 MFB-460 2005-2006 58 98 PUMP EFFICIENCY/GAS 18 MEL-170 2006 69 100 PUMP EFFICIENCY/GAS 19 11M-269 2005 1283 1506 PUMP EFFICIENCY/GAS 20 MFB-398 2008-2009 47 56 WATER CUT REDUCTION21 MFB-460 2008-2009 105 115 PUMP EFFICIENCY/GAS 22 MFB-582 2008-2009 79 118 WATER CUT REDUCTION23 MFA-70 2008-2009 17 78 PUMP EFFICIENCY/GAS 24 JOC-627 2008-2009 40 94 WATER CUT REDUCTION25 PCPOS MFB-656 2007-2008 800 900 PUMP EFFICIENCY/GAS 26 MFB-659 2007-2008 780 900 PUMP EFFICIENCY/GAS 27 MFB-670 2007-2008 270 450 PUMP EFFICIENCY/GAS 28 PDVSA MFB-669 2014 190 234 PUMP EFFICIENCY/GAS 29 AWPA NZZ-177 2010-2014 603 772 WATER CUT REDUCTION30 NZZ-217 2010-2014 688 1147 WATER CUT REDUCTION31 NZZ-246 2010-2014 100 270 WATER CUT REDUCTION32 CH-502 2014-2015 689 742 PUMP EFFICIENCY/GAS 33 CH-508 2014-2015 312 355 PUMP EFFICIENCY/GAS 34 SOE NZZ-196 2015 441 518 WATER CUT CONTROL

SUCCESSFUL AUTOMATIC CASING GAS PRESSURIZATION EVALUATION

During the bottom hole pressurization process water flow tends to recede, hence the process of displacement is reversed from drainage to imbibition, reducing the krw.

Water relative permeability reduction by the hysteresis phenomenon in an oil wet porous medium.

Theoretical BackgroundHysteresis of permeability curves

Theoretical BackgroundLab test ,Krw/Kro vs Sw vs P

•Develop a mathematical model to obtain realtive permeability curves as a function of the pressure in a water oil system•Predict the effect of the pressure over the behaviour of the water oil interpahse in the porous media• Design Relative Permeability curves as a function of pressure in a water oil system

0.01

0.1

1

10

100

1000

10000

0 0.2 0.4 0.6 0.8 1

krw/kro

Sw

RP = 2% RP = 20% RP = 50% RP = 80%

LAB MATH MODEL

EQUIPMENT MODIFICATION INPELUZ LAB

CELDA TRIAXIAL

Antes Después

PRELIMINARY RESULTS INPELUZ LAB TESTS

Información General

PRELIMINARY RESULTS INPELUZ LAB TESTS

ko: 33,88 mD

PRELIMINARY RESULTS INPELUZ LAB TESTS

0.1

1

10

100

1000

10000

100000

1000000

0 10 20 30 40 50 60 70 80 90 100

krw/kro, adim.

Sat. de Agua, % Espacio Poroso

Well CompletionWell Completion

DIAGRAMA DE COMPLETACION

.

Operational Schematic automatic casing control

PIP = 390 Psig

Pwf = 450 Psig455 453 450

Pc = 290,1 Psi

ΔP= 1,6 lpc

Pc = 288,5 Psi

Pc = 288,5 Lpc

Poper = 289,3 Lpc

Pc = 290,1 Lpc

Increase in pump Efficiency

PIP: 280 psi

PWF2

PIP :200 psi

PWF1

AGUA

PETROLEO

PETROLEOAGUA

GAS

GAS

Anular

Schematic for automatic valve control

Components of SOE equipment

Functional schematic of a well optimization system

INCREMENT AND WELL

MONITORING OF

VARIABLES IN WELL SURFACE AND GROUND

DOWN

CONTROL OF CASING PRESSURE

 

EXPERT SYSTEM ANALYZES AND MAKES DECISIONS ACCORDING

TO ESTABLISHED

PARAMETERS

CONTINOUS MEASUREMENT

OF WATER CUT   

 

DEFINE OPTIMAL OPERATIONAL

PARAMETERS TO BE PROGRAMMED

PRODUCTION

STABILIZATION

AUTOMATIC CONTROL ON

SURFACE

MUESTRAS POZO NZZ-196

42,6

22

36

26

2016

19

38,48

19

400

26 2832

36

6

1620 20

3432 30

24

34

2824

2024

14

26

2024 24

2024

29

13

40

9

42

05

10

15

2025

3035

4045

50

FECH

A

28-Sep

23-Oct

30-Oct

13-Nov

26-Nov

05-Feb

05-Feb

05-Feb

05-Feb

07-Feb

07-Feb

07-Feb

07-Feb

07-Feb

07-Feb

07-Feb

07-Feb

09-Feb

09-Feb

09-Feb

09-Feb

09-Feb

09-Feb

10-Feb

12-Feb

05-Mar

12-Mar

13-Mar

07/Abr

11/04/15

27/04/15

20/05/15

02/06/15

08/06/15

09/06/15

11/06/15

11/06/15

13/06/15

14/06/15

FECHA

%A

yS

%AyS

Manual Water Cut NZZ-196

Water cut fluctuation due to: single water cut measurement , Water cut average, and continous sampling, manual operation of SOE till June

Electronic measurement of water cut, Sentech

Water cut comparison

Agar utilize a microwave transmitter to measure bulk dielectric properties of the flow stream

Sentech technology, based on an electronic oscillator that is influenced by the dielectric constant of the media surrounding it.

Well test detail Nzz-196

DATE BFPD BOPD WATER CUT

WC MEASUREMENT

SOE CONTROLL TEST EQUIPMENT % OIL

      WC (%)        

05/02/2015 630 440 32 AVERAGE NONE TANK  

               

07/02/2015 690 490 33 AVERAGE MANUAL PORTABLE TANK 11

               

12/04/2015 692 398 43 AGAR MANUAL AGAR -10

               

13/06/2015 756 518 31 AGAR AUTOMATIC AGAR 18

               

30/07/2015 729 517 29 SENTECH/SOE AUTOMATIC SEPARATOR 18

               

12/08/2015 712 491 30,5 SENTECH/SOE AUTOMATIC SEPARATOR 12

               

13/09/2015 708 488 30,5 SENTECH/SOE AUTOMATIC SEPARATOR 11

               

13/10/2015 740 460 35,3 SENTECH/SOE AUTOMATIC SEPARATOR 5

Well tests Nzz-196WELL TEST

0

100

200

300

400

500

600

05/02/2015 07/02/2015 12/04/2015 13/06/2015 30/07/2015 12/08/2015 13/09/2015 13/10/2015

DATE

BO

PD

0

5

10

15

20

25

30

35

40

45

50

WA

TE

R C

UT

(%

)

WC (%)

INITIAL TESTMANUALOPERATIONAUTOMATICOPERATIONSOE

Conclussions

• 1. - After automatic control of casing pressure has been established at its optimal point, SOE has controlled in well NZZ-196 water cut, and improved pump efficiency, increasing oil well production by a 13% average .

• 2.- Best water cut accuracy measurement is obtained through electronic monitoring, using equipment such as Agar or Sentech, if these equipments are not available, then a fair water cut measurement can be calculated by sampling continuously or getting an average, and lastly through a one sample collection at the wellhead

• 3.- Preliminary lab tests have shown a correlation of relative permeability of oil and water with different pressures and water saturation , in order to determine the optimal flowing pressure.