Well Performance

ENHANCING WELL PERFORMANCE

Edmond NGALEMO

PETROM TECH DAY, SEP 07

AGENDA


WELL PERFORMANCE




WELL PROBLEMS




WELL PERFORMANCE EVALUATION




PRODUCTION LOGGING




OPTIONS FOR ENHANCEMENT

WELL PERFORMANCE




FACTORS EFFECTING WELL PERFORMANCE • • •

RESERVOIR STRUCTURE DRIVE MECHANISM COMPLETION SYSTEM

RESERVOIR

RECOVERY

COMPLETION

WELL PROBLEMS

WELL PROBLEMS

WELL PROBLEMS

WELL PERFORMANCE EVALUATION


RESERVOIR • • •




WELL INTEGRITY • •




Hydrocarbon – water contact Detect thief zone Well test Mechanical problems Channeled cement

COMPLETION • • •

Zonal contribution (injection, production) Water breakthrough, coning Treatment effectiveness

PRODUCTION LOGGING PRODUCTION LOGGING PROVIDES DETAILED INFORMATION ON THE NATURE AND BEHAVIOR OF FLUIDS IN THE WELL DURING PRODUCTION OR INJECTION.

PL MEASUREMENTS


TEMPERATURE




PRESSURE




TUBING/CASING SIZE




FLOW DISTRIBUTION • •

RATE HOLD UP

PL SERVICES

















Thermometer Manometer (sapphire gauge, quartz gauge) Fluid density (gradiomanometer, nuclear) Flowmeters (continuous, fullbore) FloView (digital fluid entry tool) GHOST (Gas holdup optical sensor tool) FSI (floscan imager) Gamma Ray CCL Noise (single frequency, multiple frequency) Caliper Radioactive tracer Water flow logging Gravel pack logging Three-phase holdup Downhole video

SWBS WEIGHT SWRS ROLLER PBMS GR, CCL, Temp, Press

PILS INLINE SPINNER

PGMC GRADIO-MANOMETER

GHOST OPTICAL PROBES

PFCS SPINNER, ELECTRICAL PROBES

THERMOMETER


PRINCIPLE OF OPERATION •

Platinum temperature resistor




First log down 1800 ft/hr




SPECIFICATIONS • • •

Range: Resolution: Accuracy:

– 25 °C to 150 °C 0.006 °C ± 1 °C

TEMPERATURE APPLICATIONS


LOCATION OF FLUID ENTRIES




DETERMINATION OF FLOW BEHIND PIPE




DETECTION OF GAS PRODUCTION




QUALITATIVE EVALUATION OF FLUID FLOW




DOWNHOLE TEMPERATURE INFORMATION




EVALUATION OF FRACTURE TREATMENTS




EVALUATION OF MECHANICAL INTEGRITY OF A COMPLETION

TYPICAL TEMPERATURE LOG

DISTRIBUTED TEMPEATURE SENSOR


RealReal-time monitoring of temperature • • •




Faster, better decisions • • •







water / gas breakthrough, steam management zonal isolation, well integrity injection monitoring, artificial lift performance

Reduced operating costs • •




Continuous data without well intervention. Sensor: fiber optic technology real-time transmission of downhole data

minimizing the need for production logs minimizing production losses

Specifications Depth: Sensing length: Sample spacing: Temp/Press: Resolution: 0.05 degC

up to 30 km 12 km 1m 150oC / 10 kpsi

Not suitable for all wells (Resolution)

PRESSURE GAUGES STRAIN

QUARTZ




STRAIN GAUGE

ELECTRONICS


– PAINE – SAPPHIRE


QUARTZ GAUGE – CONVENTIONAL – COMPENSATED

ACQUISITION FREQUENCY – FAST GAUGES – SLOW GAUGES




RESOLUTION




NOISE

Pressure (psia)

SENSORS

ACCURACY, RESOLUTION, REPEATABILITY SENSITIVITY, TRANSIENT RESPONSE (STABILIZATION)

PRESSURE GAUGE Specification


ACCURACY •




RESOLUTION •







Maximum difference between measurements of the same pressure.

SENSITIVITY •




Minimum pressure change that is detected by the gauge.

REPEATABILITY •




Difference between a measured value and the true value obtained from a reference standard.

Ratio of the induced variation in the transducer output to the change in applied pressure.

TRANSIENT RESPONSES TO TEMPERATURE VARIATIONS TRANSIENT RESPONSES TO PRESSURE VARIATIONS

PRESSURE GAUGES

Specification Accuracy Repeatability Resolution Temperature rating Pressure rating

CQG Quartz Gauge Sapphire Gauge 2.0 psi + 0.01% of reading ± 5 psi + 0.01% of reading 1.0 psi 0.01 psi at 1Hz 0.05 psi at 1Hz 302°F (150°C) 302°F (150°C) 15 kpsi 10 kpsi

PSOI (differential) ± 0.015 psi

302°F (150°C) ± 20 psi

PRESSURE APPLICATIONS


DOWNHOLE PRESSURE INFORMATION for PVT evaluations • • •

Fluid compression – shrinkage GOR Downhole to Surface / Surface to Downhole conversions




DERIVE FLUID DENSITY




RESERVOIR CHARACTERISTICS from pressure transient analysis • • • • • •

permeability(k) permeability thickness (kh), formation skin factor (s) reservoir extent and boundaries productivity index absolute open flow potential (AOFP, see glossary).

SPINNER FLOWMETER Magnet

PRINCIPLE OF OPERATION


IMPELLER ROTATES AS FLUID MOVES




ROTATIONAL SPEED IS MEASURED ELECTRICALLY (RPS)




FLUID FLOW DERIVED FROM CALIBRATION OF RPS

Coils

Spinner blades

APPLICATONS


QUANTITATIVE FLUID MOVEMENT WITHIN THE WELL ON A ZONEBY-ZONE BASIS.

SPINNER FLOWMETER SPECIFICATIONS Flowmeters

Continuous

Fullbore

Tool diameter in tubing (in)

1 11/16, 2 1/8, 2 7/8

1 11/16

Spinner diameter (mm)

30, 42, 61

57, 89, 127, 178

Minimum flow rate (B/D)(1)

400

200

Temperature (°C) (

150

150

Pressure (psi)

15000

20000

(1) (7-in. casing) Minimum flow rates correspond to single-phase flow. Minimum flow rates for multiphase flow vary according to the fluid properties of the mixture.

SPINNER CALIBRATION InIn-Situ Flowmeter Calibration Plot E

E

RPS D C

m

D

B

y

A C

Up

Vt

Down Cable Speed

B

y=mx+c x=(1/m)y+d V=(1/m)RPS+Vt

A 0 + Cable Speed

-

0 RPS

+

Vm = ( RPS / Slope ) + Vt – CS Vm = ( RPS . Pitch ) + Vt – CS

SPINNER – MIXTURE APPARENT VELOCITY

turbulent

laminar

GRADIOMANOMETER FLUID DENSITY TOOL PRINCIPLE OF OPERATION

∆P + ρso ρf = g h cosθ

FACTORS AFFECTING GRADIO TOOL MOTION KINETIC JETTING FRICTION

GRADIOMANOMETER SPECIFICATIONS Differential pressure transducers

PSOI

Manufacturer

Schlumberger

Temperature range

175°C

Overpressure without decalibration

± 20 psi

Accuracy

0.015 psi (1)

Burst pressure

40 psi

Shocks and vibrations (3)

Class 6 (500 g/2 ms)

DST and TCP resistance

Yes

(1)Including P&T hysteresis, fitting error and repeatability (1)

GRADIOMANOMETER PGMC SPECIFICATIONS

Range

0 to 2 g/cc

Accuracy

± 0.04 g/cc (below 20 deviation)

Resolution

0.002 g/cc

GRADIOMANOMETER APPLICATIONS


DETERMINE FLUID HOLD UP •




FROM AVERAGE DENSITY

DETECT ENTRY POINTS

LIMITATIONS


DEVIATED WELLS




FLUID LAYERING




LOW CONTRAST BETWEEN FLUID

ELECTRICAL PROBES PRINCIPLE OF OPERATION

Probe sensitive to fluid conductivity Output is binary Water holdup Hw = White time / Total Time Hydrocarbon Holdup Hh = 1 – Hw Bubble count BBC = Σ bubbles /second

ELECTRICAL PROBES PFCS SPECIFICATIONS

Accuracy

Bubble Count

5 % water (2% when Yw>90)

10% for bubble size > 1mm

Maximum fluid velocity 2 m/s (telemetry), 1m/s (memory) Minimum water salinity 1,000 ppm @ 100degC 2,000 ppm @ 25 degC …. Charts

ELECTRICAL PROBES APPLICATIONS


LOCATING FIRST OIL/WATER ENTRIES, WITH HIGH RESOLUTION




WATER HOLDUP MEASUREMENT ⇒ FLOW RATE COMPUTATION

FLOVIEW LOG

Stratified flow in horizontal well

First oil entry

OPTICAL PROBES

Incident light (Ii)

(Ir) Ir) Reflected light

PRINCIPLE OF OPERATION

Ir/Ii ? Probe sensitive to fluid refractive index Output is binary Gas holdup Hg = Black time / Total Time Liquid Holdup HLiquid = 1 – Hg Bubble count BBC = Σ bubbles /second

OPTICAL PROBES GHOST SPECIFICATIONS

Accuracy

Bubble Count

7% standard probe 5% probes without protectors 1 % If Yg > 98 % or < 2 % 1% for Bubble size > 0.002 in or 0.1mm

Maximum fluid velocity 8 m/s (covers most of velocity ranges)

OPTICAL PROBES APPLICATIONS


LOCATE FIRST GAS/LIQUID ENTRIES, WITH HIGH RESOLUTION




GAS HOLDUP MEASUREMENT ⇒ FLOW RATE COMPUTATION

FLOVIEW – GHOST LOG

GR


CORRELATION • •




Depth matching between separate trips in the well. Providing the depth control needed for cased hole operation

IDENTIFICATION OF RADIOACTIVE ZONES (SCALES) IN PRODUCING WELL

CCL


CORRELATION IN CASED HOLE

Operates in ferromagnetic pipes

PIPE

CCL

MULTIPHASE FLOW

FLOWRATE-VELOCITIES-HOLDUP-CUT Yw

Vw

Yo

Holdup

Yw + Yo = 1

Flowrates

Qw = Yw * Vw * Area Qo = Yo * Vo * Area Qtot = Qw + Qo

Slippage Velocity

Vs = Vo - Vw

Superficial Velocity

Vsupoil= Vsupoil= Qo / Area Vsupwater = Qw / Area

Mixture Velocity

Vmix = Qtot / Area Vmix = Σ Vsup

Water Cut

BS&W = Qw / Qtot

Vo

OPTIONS FOR ENHANCEMENT










WATER SHUT OFF SQUEEZE JOBS TUBING / CASING PATCHES HYDRAULIC FRACTURING MATRIX ACIDIZING SAND CONTROL PERFORATING - REPERFORATION MULTIPLE COMPLETIONS ARTIFICIAL LIFT

THROUGH TUBING CEMENT PLUGS

TOTEA EXAMPLE – PRODUCTION LOG

WELL PERFORMANCE

THANKS

MANOMETER


PRINCIPLE OF OPERATION •




Force summing device

GAUGES • • • • •

Paine gauge Sapphire gauge Hewlett-Packard gauge QuartzdyneTM gauge Compensated quartz gauge