PRODUCTION LOG INTERPRETED LOG. PRODUCTION LOGGING FOR F.ENG.'S Why should we Production Log Wells?...

Production Logging for Field Engineers

PRODUCTION LOG INTERPRETED LOG

prepared by:

Ahmed Abu-Shloua

PRODUCTION LOGGING FOR F.ENG.'S

Why should we Production Log Wells?

“In the year 2003 seven barrels of water are being produced for every barrel of oil.

This trend is set to continue.” “Oil is a finite reserve, wells are getting older, we have to be more efficient”

“It cost more to produce water than to produce oil”

“The only way to find out what is happening downhole, for sure, is to lower toolsto the bottom of the well and measure what is happening.”

What do we gain?• Information to assist in solving problems now and in the future.

The AIM?• To maximise the ultimate oil / gas recovery.

• To justify the cost of remedial work or even the development of an entire field.


What is the well producing?• OIL• GAS

• WATERWhat do we want?

Definitely Oil, Gas if we have a pipeline but not if it limits oil production.What do we not want?

Water!Water costs more produce than oil because we have to dispose of it!

24%

10%

45%

14%7%

Production Profiling

Injection Profiling

Water Problems

Excessive Gas Problems

Mechanical Problems


KRA 4

0 150GAMMA RAY (API)

-150 150LSP DN 30 Ft/M (RPS)

-150 150LSP DN 50 Ft/M (RPS)

-150 150LSP DN 75 Ft/M (RPS)

-150 150LSP UP 30 Ft/M (RPS)

-150 150LSP UP 50 Ft/M (RPS)

-150 150LSP UP 75 Ft/M (RPS)

0150CCL

-10 40SPNR DN 30 Ft/M (RPS)



-10 40SPNR UP 30 Ft/M (RPS)



260 275TEMPERATURE (DEG F)

1500 1700PRESSURE (PSIA)

4000 0FLUID CAPACITANCE

0 2DENSITY (g/cc)

8100

8150

8200

8250

8300

8350

8400

8450

8500

8550

CCL tells usthe perfs arein the right location

Gamma Rayindicates thatonly the cleanestsands (below 30API) are productive.

Flowmeter showsthat this section ofperfs is not

productive.

Fluid IDtells uswhich fluidsare being produced

An example of: Profiling a New Well

Temperature indicates cooling with gas production

An example of: Production ProfilingTo save money on an Exploration Well

The oil company wanted to confirm the gas oil contact in thisexploration well.

The floating rig was costing$120,000 per day.To test 4 zones wouldbe 10 days = $1,200,000.

A single test taking 2.5 dayscovering all 4 zones with aPLT job cost US$ 300,000

What would happen if the tools failed or the spinner did not work?.This well was making 5000 BOPD. If it was a production well andwe had a mis-run the deferment of 12hrs oil would be $50,000.• Reliability is important financially and for our reputation.

Where is the Gas / Oilcontact?

(Remember gasproduction has acooling effect andvolumes are large)



An Example of: Quantifying Water Production Excess water production will limit oil productionProduction Log Interpreted Data


An example of: Injection Profiling

Spinner shows negativerotation as flow is negative

No apparent injectioninto this zone BUT thetemperature does not returnto geothermal straight awaywhich shows thatthere is a little injectionbut it is not measurable.

This zone is‘HOT’

This zone is ‘NOT’

WHY?

Clue: RadioActive scale depositionoccurs withwater production.A. This well was once a producer and one zone watered out (but not the others)


How our tools are used to measure the flowrates ofoil, gas and water from each zone.

The Magnificent 7:

PressureCCLGamma RayTemperature - Fluid MovementFluid Capacitance - Fluid IDDensity - Fluid IDFlowmeter - Total Flow

Others:CentralisersX-Y CaliperGas HoldupIn Line Spinner Capacitance Array Tool etc

CFSContinuousRoller Bearing SpinnerFlowmeter

CFBContinuous FullboreFlowmeters

PRCRollerCentraliser

PSCSpringbowCentraliser(Open Hole Completions)

FDRRadioactiveFluidDensity

FDDdPFluidDensity

ILSIn-LineSpinner

DBTDiverterBasketFlowmeter

PGRScintillationGammaRayPKJ

ConductingKnuckleJoint

CTFCombinedCapacitanceFast ResponseTemperatureand Spinner rotationpickup.

QPCCombined QuartzPressureCasingCollarLocation

PSJSwivelJoint

MPLMemory PLRecorder

MBHBatteryHousing

For Memory PLT exchange XTUwith MPL and MBH

Monoconductor Wireline

SRO PL AcquisitionSystem

Short Compact StringUsing Notebook PC

Power Supply / TelemetryPanel with Printer

Notebook PCDepthEncoder

XTUUltralink ControllerSROTelemetry Sub

PDCDualX-YCaliper(Bowspringfor Open Hole)

CFJContinuousJewelled Bearing SpinnerFlowmeter

Interchangeable

USB forData

Parallelfor Printer

UltralinkSRO Telemetry

UltrawireTool bus Telemetry


Temperature

Pressure: QuartzCrystal

-The crystal has a natural oscillation.As pressure increases the oscillation decreases.As temperature increases the oscillation increases.We measure the pressurefrequency and crystal temperatureto correct the pressure reading.

CCL-Changes in metal volumemove the lines of magneticflux within a coil. This generatesa voltage.

-Changes in temperaturealter the resistance of a Platinum wire. Consequently There is a varying voltage Differential across the probeWith temperature change.

Theory of operation and use of tools


Gamma RayTool

Sodium Iodide Crystal

Photo Multiplier Tube

High Voltage Power Supply

Detector

Capacitance WaterHoldup

CapacitorPlates

Fluid Path

Hydrocarbons and Water have differentdielectric constants. The speed the capacitorcharges up gives us a:High Frequencies in oil / gasLow frequency in water


High Voltage Power Supply

GammaRay Path

Radio Active Density

Sodium Iodide CrystalPhoto Multiplier Tube

Detector

Americium RadioactiveSource

Fluid Flow Path

Differential Pressure Density (FDD)

Wellbore Inside Tool

2ftSiliconOil

In Gas:

DifferentialPressure is HIGH

Wellbore Inside Tool

2ft SiliconOil

In Water:

DifferentialPressure is LOW

DP Sensor

2ft GAS 2ft WATER


Flowmeters: (The King of the PL tools).All are spinner type. The faster the spinner rotates, the faster the flowrate.Tools are chosen to match the completion

Swab Valve

Crown Valve

Wing Valve

20” Casing

13 3/8” Casing

9 5/8” Casing

Reservoir A

Perforations Packer

End Of Tubing

Cement

Tubing

Tubing Hanger

WELLHEAD

SSD for Circulation

SafetyValve

Reservoir B

In this case we use a CFB

Multiple Zone Completions

Zone C

Zone B

Zone A

Single String Dual String

Sliding Side Door(Sleeve Valve)

TubingIn 9 5/8” Casing4.5-5.5”In 7” Casing3.5”

TubingIn 9 5/8” Casing2.875”In 7” Casing2.375”

SSD’s may be opened andclosed by tools run on

wireline

Dual Completions offermore flexibility such as injecting down one string and producing the other buttubing size is limited.

Short StringLong String

Log in tubing withcontinuous spinners. Log in casing withfullbore spinners.

Dual strings allow production from zonesat very different pressures

Zone D

Nipple for Plug

In this case we use a CFB and ILSSIZE matters!


Production Logging Quantitative AnalysisStep 1: Determine Total Flowrate

In-Situ Calibration at different line speeds.Gives response slope and Intercept (threshold).

Spinner Crossplot

y = 0.0547x + 0.0229

y = 0.0603x - 0.3674

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

-200 -150 -100 -50 0 50 100 150 200

Line Speed

Spi

nner

RP

S

Dow nw ard

Upw ard

Linear (Upw ard)

Linear (Dow nw ard)Line Speed / Fluid Vel

SpinnerRPS

Fluid Velocity = (RPS/Slope + Threshold) - Line Speed

Measure Fluid Velocity is corrected to average velocity allowing for spinner size in relation to wellbore and also for the flow regime.

Single Phase (Oil, Gas or Water) Barrels/Day = Average Velocity (ft/min) x 1.4 x ID”^2

1000 BPD is:9.6 ft/min in 9 5/8” Casing18.6 ft/min in 7” Casing79.8 ft/min in 3 1/2” Tubing


Step 2: Calculate the fraction of each phase in the wellbore (holdup) - 2 Phase flow.

DENSITY vs HOLDUP

0.7

0.8

0.9

1

1.1

1.2

0 0.5 1

Water Holdup, fraction

Log

Den

sity

, g/c

c

Water Density

Oil Density

Heavy Holdup = Density Measured - Density Light Density Heavy - Density Light

Light Holdup =1 - Heavy Holdup

Water Holdup is a direct measurement.

Due to non linearity and othereffects Density is usually morereliable.

Fractional Response CWH vs Water Holdup

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1


Fra

ctio

nal

Res

po

nse

From DENSITY

From CAPACITANCE

Water Freq.

Oil Freq.


Step 2a:Calculate the fraction of each phase in the wellbore (holdup) - 3 Phase flow.

A) Determine Water Holdupfrom Capacitance Tool

B) Knowing water holdup andwater density use theDENSITY data to determineoil and gas holdups

Water Holdup – directly from CWH tool.

Oil holdup, Yo =

((dens meas - dens gas) + Yw (dens gas - dens water)) (dens oil - dens gas)

Gas holdup, Yg = 1 - Yw - Yo


Step 3:Determine the slip velocity

Slip velocity is the difference in velocity between one phase and another.The light phase travels up the well faster than the heavy phase.

This is one of the great unknowns – many different correlations are available.

Slip Velocity vs Holdup

0.0020.0040.0060.0080.00

0.00 0.50 1.00

Water Holdup (Fraction)

Ligh

t Pha

seSl

ip V

eloc

ity

ft/m

in

Oil 0.8 g/cc

Oil 0.7 g/cc

Gas


Step 4: Calculate the superficial fluid velocity of each phase.

If NO slip: Superficial Velocity = Total Velocity x holdupFor example if flow was 100 ft/min and water holdup was 0.5Water flow would be 50 ft/min and oil flow 50 ft/min.

Problem is that THERE IS slip! Oil Superficial Velocity =(Oil holdup x Total Velocity) + Extra Oil flow due to slip

Water Superficial Velocity = (Water holdup x Total Velocity) - Extra Oil flow due to slip

Qheavy ft/min = (Yh x Qtotal ft/min) – (Yh x (Yl x Vslip light ft/min))

Qlight ft/min = Qtotal ft/min – Qheavy ft/min

Step 5: Convert to Downhole Volumetric FlowrateDownhole volumetric rate, BPD = Superficial Velocity, ft/min x 1.4 x ID”^2

Step 6: Convert to Surface Volumetric FlowratesSURFACE volumetric rate = Downhole / Correction Factor to Surface Conditions (FVF)

Oil is travelling up at slip velocity

Water is falling backdown around oilbubbles


Production Profiling: Decision made from log dataAn example interpretation of a production well log

Injection Well Production Well

This production well was producingat 76% water cut.The client presumed that the bottomzone had watered out and wantedto plug off the zone.

Proposed location ofbridge plug

Before performing the job one ofthe engineers proposed a PLT job to check.


The Production Log andInterpretation Method

Using the calibration crossplot theSpinner data gives us total flowrate

When we know the downhole density of oil and water we can use density datato give us the downhole water holdup.

DENSITY vs HOLDUP

0.7

0.8

0.9

1

1.1

1.2

0 0.5 1


Lo

g D

en

sity

, g/c

c

We could also have usedCapacitance for holdup.


The Interpreted Data

WATER IS COMING FROMALL THE ZONES.

OIL IS COMING FROMTHE ZONE BELOW WHEREWE WANTED TO SET THEBRIDGE PLUG

High Gamma Ray indicatesRA scale which is associatedwith water production. Lendsconfidence to the analysis.


The Results of the Interpretation

Zone 1: 89% Water Cut




All the zones have high water cut.

If the client had set the bridge plug:A lot of money would have been spent and 515 BOPD of production fromZone 4 would have been left in the ground.

There would be no gain: The well would remain at 76% water cut (total of zones 1 to 3) and because the water cut is the same the BHP, hence flowrate would say the same.

The total water cut is 76% of which:

Zone 1

Zone 2

Zone 3

Zone 4


Where Next ?: This Horizontal Well Production Log was recorded using memory PL tools on coiled tubing. Why is it so good?Because it is 99% water!

After 8,000,000 bbls oilproduction this is the newoil / water contact.

The CWHtool shows hydrocarbonsonly at thehighestpoint of thewell. The rest of the production iswater.

Horizontal WellTrajectory

1300m TVD

1325m TVD

Depth:


This is what multi-phase logs run using conventional CentreSampling tools look like!

WATERFreq.

GASFreq.

THERE MUST BE A BETTER WAY!


Geometry of CAT Sensors

Simultaneous measurement of sensors close to the casing circumference provides a cross-section in partially segregated multi-phase flows.

GAS

OIL

WATER


Flow profile from Capacitance Array Tool

Bubbles of oil passing through trough

Stream of oil passingby at the top

Gas has enteredthe well


CATview Imaging Software - side viewWater = Blue, Oil = Red, Gas = Yellow


Planning a PLT job

1-WELL INFORMATIONComplete Well bore diagram showing ID's and depths of all down hole hardware.Complete proposed logging program.Shut-in Wellhead Pressure.Flowing Wellhead Pressure. (For each flow rate)Expected Flowrates to be used during logging program.Expected fluid phases.Well Deviation.Pressure Build up/Draw down required.Production rates of Gas/Oil/Water.Sand production.Concentrations of H2S/CO2 present. (Needed for inhibitor considerations and choice of O Ringand cable head boot material).Natural or artificial lift.Type of lift system. (Gaslift, Submersible pump).Special requirements for lift system. ("Y" tool for logging below a submersible pump; Gaslift Side Pocket Mandrels (SPM)).Need "Y" tool plug and hammer.Details of SPM. (Special full bore flowmeter cage required?)


Production Casing data.• Outside Diameter.• Weight/Foot.• Total Depth and date of last T.D. check.• Outside Diameter of tool used to check T.D.• Type of depth measurement, wireline or logging.• Perforated intervals.• Type of charges/carrier used for perforating.• Position of any squeezed perforations.• Gravel pack.

Production Tubing data• Tubing end.• Outside Diameter.• Weight/Foot.• Diameter of the smallest restriction in the well.• Position of other down hole hardware.• ID/OD of protection/separation sleeve. (Protects the seat when DHSV is removed)

Wellhead Connection.• Swab Valve present on tree. (A swab valve is required to shut in the well above the• flowline and permit installation of pressure equipment• without disturbance of the normal well flow.)• Flange or Threaded. (Size and Thread type).• Measurement Reference.

Rotary Table (RT) to Tubing Hanger (TH) measurement.


3.PL Job Planning

Establish with the client the objectives of the job.

Is there a logging program? Write the logging program to meet the objectives

Does the program meet the objectives

Does the well have a history of problems or a hostile environment?

Discuss with the client and plan accordingly.

Estimate the downhole flowrate and flow regime and select which tools to use

No

Yes

No

No

Yes

Perform Tool Lift Estimation

Flow too high?

Start Logging Job

Is well stable and ready to be logged?

Perform Logging Job

Can we add weight?

Limit Flowrate

Wait for well to be stable

No

NoYes

Yes

Yes

Yes

No


Rig Up Tools

EditDepth Menu

Setup Encoderon Wireline / CTU unit

Test depth measurement.Edit setup if necessary

Set Zero and startrecording data

Perform Production LoggingJob

Refine Depth correlationof each pass and logging

stations

Export on-depth LAS data for interpretation and client

and for Sondex crossplots

Make headers, crossplots etc. for API strip log.

Print Log

Edit toolstring configurationEdit Calibration Files

Edit Log Presentation FilesCreate Warrior Database

Check tools are working properly.

Make Pre-job Calibrations and check calculated output

Make Post-job Calibrations and check calculated output

Run In Hole

Depth correlate tools

4. Warrior SRO PLT flow chart


5.Warrior Log Printing Flowchart

Data in Warrior DatabaseWarrior Import

MPL Depth and Time Drive .LAS Files

Surface Readout Acquisition

Data RecalculationSRO data only

Depth Correlateand Shift Curves

Edited Presentation Files .PRS using

Format Editor

Merge Log passesusing Automerge

Add:Annotations,Log Banners,Well Sketch

Export depth correlated LAS

files using

LAS Writer

Make SpinnerCrossplots printout as

.PRN files

Edit Header

Additional ASCIIFiles (logging stationstatistics, log tail, other info etc)

Plot Job Editor to buildthe sequence of logs

PLOT THE LOG

Memory PLAcquisition

Use Service Builder togenerate toolstring

Log toolstringdiagram to Warrior

Database

Edit Warrior Import Filter Files


What can go wrong ??

The order of seriousness as to what can go wrong is:

A. The tools may be lost in hole.B. The tools may fail.C. The client may not get the data he needs.


A) The tools may be lost in hole.

What can you do to minimise the risk of losing your tools?

• Check well history• Your wire line equipment; up-to-the job?!• Pre –job toolbox meeting.• Well trajectory and max. tool straight length.• Maximum restriction.• Tool lift estimation.• Job supervision against unwise suggestions.• Tool catchers & tool traps beside the hydraulic relief valve.• Avoid right angle tips in your downhole string.• Radioactive tools should placed above weak points in your PLT

string.• Avoid running in hole during a sluggy flowing condition.• X-mass valves should be operated under your supervision.

Discuss:What do you do if the tools are stuck in hole?What do you do if the tools are dropped or lost in hole?


B) The tools may fail .

What can you do to avoid tool failure:•Check max. downhole temperature & pressure.•Lower running speeds to avoid tool jerking.•Have a backup string on site.•If running memory tools, check battery specifications and calculate the estimated power consumption under downhole conditions (not on surface..!!)•If running MPL avoid quick bleeding your lubricator after coming out of hole.•Check and replace O’rings to suit your application and to adhere to any possible CO2 & H2S existence.•During surface check; the tool’s raw data (Sensor raw reading)should be monitored before checking the calibrated output in “Outputs” window.•Operation with GLM’s existence:•Use Bow-Spring Full bore-mechanical-spinner sections.•Use the right size to avoid blades extraction while running thru a GLM.•Increase the tool length between full-gauge ancillaries to be more than the GLM length.•If there’s junk in the well, consider running a continuous spinner.

Discuss: Specific precautions pertaining to individual tools


C) The client may not get the data he needs.

•See what if the client required data is attainable by your PLT job. For example: He may need to log fluid contacts behind casing or to flow-profile multiple zones producing thru SSD.

•If you are running MPL job & the Slick line cannot attain a steady speed;the spinner data shall be invalid.Then consider conducting lots of stations,say on a 5 ft intervals.

Run the correct tools•Choose the right spinner mecahinical sections to suit your application and consider having an inline spinner as a backup.•To get good CCL’s use knuckle joints or modify your tools order to be able to de-centralise your CCL as much as you can.•Allow for well stabilisation.•Allow for delays.(i.e. While running MPL,put in mind stabilisation periods in fast and slow sampling rates of your tools.Present the log clearlyDiscuss: Log Quality Assurance.


Finally..

We came to the end of our session….

Before say ‘Good Bye’ we are having a small test….

To tackle your minds and open some channels,in the way you think about Production Logging…

Hope to see you again in a more advanced PL course…

Farewell..!! Ahmed Abu-Shloua

PRODUCTION LOG INTERPRETED LOG. PRODUCTION LOGGING FOR F.ENG.'S Why should we Production Log Wells?...

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Transcript of PRODUCTION LOG INTERPRETED LOG. PRODUCTION LOGGING FOR F.ENG.'S Why should we Production Log Wells?...