Whoc 322

CHANGES IN ANNULUS PRESSURE, INCREASE OIL PRODUCTION

Organized by:

PDVSA

WHOC16-[322]

•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.

OBJECTIVE

NUMBER OF ACTIVE WELLS 102REMAINING OIL RESERVES 255 MM BLSPRODUCED OIL 111 MM BLSAPI 14- 18ACTIVE RESERVOIRS 4DEPTH 2700 FEET GAS RESERVES 58 MMM CFTPRODUCED GAS 43 MMM CFT PRODUCTION 24 MBOPD START UP YEAR 2003

SAN CRISTOBAL FIELD, LOCATION

RESERVOIR OFIH SCR 2, WELL NZZ-196Pi: 1287 psiPb. 1090 psi Pactual: 950 psiTr= 156 ° F ° API: 16,1Viscosity reservoir : 14,4 cpN ° active wells: 19

INTRODUCTION

1.- 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 due to improvement of pump efficiency and water cut reduction

INTRODUCTION

SUCCESSFUL AUTOMATIC CASING GAS PRESSURIZATION EVALUATION

# WELL EQUIPMENT YEAR BOPD (BEFORE) BOPD (AFTER) ORIGIN

15 MAXIPROD 98-2012 360,46 677,73 WATER CUT REDUCTION

9 SIAP 2005-2009 203,22 259,44 PUMP EFFICIENCY / GAS

3 PCPOS 2007-2008 616,66 750 PUMP EFFICIENCY / GAS

1 PDVSA 2014 190 234 PUMP EFFICIENCY / GAS

5 AWPA 2010-2015 478 657 WATER CUT REDUCTION

1 SOE 2015 441 518 PUMP EFFICIENCY / GAS

2.- In order to explain water cut reduction with this Technology , a test was designed with University of Zulia , research Institute Inpeluz with a modified triaxal cell with different core samples by the end of 2015..-

Theoretical Background Lab 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.

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

INTRODUCTIONLAB MATH MODEL

INTRODUCTION EQUIPMENT MODIFICATION INPELUZ LAB

TRIAXIAL CELL

Before After

INTRODUCTIONPRELIMINARY RESULTS INPELUZ LAB TESTS

CORE SAMPLE INFORMATION


ko: 33,88 mD


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Sat. de Agua, % Espacio PorosoWater Saturation

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Water Saturation

KRW

/ K

RO

WATER SATURATION %

Pwf = 450 Psig 455 453 450

Pc = 290,1 Psi

ΔP= 1,6 lpc

Pc = 288,5 Psi

140 Rods 1-1/4”140 Rods 1-1/4”

Pump Pump

Liner @ 4220 ftLiner @ 4220 ft

EQUIPMENT OPERATION

Control valveControl valve

INTRODUCTIONIncrease in pump Efficiency

PIP: 280 psi

PWF2

PIP :200 psi

PWF1

AGUA

PETROLEO

PETROLEOAGUA

GAS

GAS

Anular

INTRODUCTIONComponents of SOE equipment

TEMPERATURE WATER CUT MONITOR

TUBING PRESSURE

COMPUTER

CONTROL VALVE

BATTERIES

CASING PRESSURE SENSOR

INTRODUCTIONFunctional 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

INTRODUCTIONManual Water Cut Measurements NZZ-196

INCREMENT AND WELL

Water cut fluctuation due to: single water cut measurement , Water cut average,

and continous sampling, manual operation of SOE till June

% W

ATE

RCU

T

INTRODUCTION

INCREMENT AND WELL

Electronic measurement of water cut, Sentech

INTRODUCTION

INCREMENT AND WELL

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.

DATE SOE % Lab. STM % AGAR %

02-JUN-2015 29.01 26 -

08-JUN-2015 28.09 18 -

13-JUN-2015 29.65 24 30.1

INTRODUCTION

INCREMENT AND WELL

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



INTRODUCTION

INCREMENT AND WELL

Well test Nzz -196WELL TEST

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INITIAL TEST

MANUALOPERATION

AUTOMATICOPERATIONSOE

INTRODUCTION

INCREMENT AND WELL

CONCLUSIONS

1.- Preliminary lab tests have shown that the effective permeability to water decreases as a differential pressure is applied , so an oil phase moves preferentially over a water phase in a core sample at a constant value of saturation.

2.- Best water cut accuracy measurement is obtained through electronic devices, if these equipment 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.- In well NZZ-196, after automatic control of casing pressure has been established at its optimal point, the equipment has controlled water cut, and improved pump efficiency, increasing oil well production by a 13% average.

Whoc 322

Engineering

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