Cased Hole Logging

Cased Hole Logging

Cased Hole Logging

Dr. Ir.

Cased Hole Logging

• Completion Evaluation • Cement Evaluation

• Corrosion Tubular Evaluation • Perforating

Why Log?

• Fluid contact detection and movement

(material balance)

• Other water/gas movement • Injection frontal advance • Water salinity

Special Applications

• Gravel-pack monitoring

• Channeling behind casing

Formation Evaluation

Logs for cased hole formation evaluation

– Gamma ray – NGS log

– Neutron log – Sonic log

– Thermal decay time log

GR SIGMA RATIO NEAR & FAR COUNTS

TDT

Completion Evaluation

Production logging applications

– Well performance – Well problems

– Well testing

– Single and multi phase flow – Flow anomalies

Completion Evaluation

• Detecting mechanical problems,

breakthrough, coning

• Providing guidance for workovers,

enhanced recovery projects

• Evaluating stimulation treatment

effectiveness

• Monitoring and profiling of production

Completion Evaluation

cement

• Single layer and multiple layer well test

evaluation

• Determining reservoir characteristics • Identifying reservoir boundaries for

Completion Evaluation

Production logging tools

– Spinner flow meters

– Radioactive tracer tools – Fluid density tools

– Nuclear fluid density tools – Temperature tools

25% 65% 75% 100% PLT GR OH GR 9300 9200 9100 9400 9500 9000 CAL Gamma Ray 0 API 500 2 7 0 28000 Caliper Inches Pressure 4000 PSIA 4200 Total Flow BPD 0.2 1.2 Density g/cm3 0 28000 Total Flow 240 245 Temperature °F 240 245 Temperature °F 0 28000 Flow Rates BPD Diphasic Analysis 0.2 1.2 Density g/cm3 Flowing Shut-in Flowing Shut-in

Weights PCM/CCL Telemetry 10” motorized centralizer Gamma ray Fluid density Temperature Pressure

10” Bow spring centralizer Continuous spinner flowmeter

Fullbore flowmeter Gradiomanometer Thermometer/ Strain-gauge Centralizer In-line flowmeter

Quartz pressure gauge Caliper Telemetry cartridge, including GR detector Collar locator Thru-tubing guide (Centralizer) Weights Cable head

The Schlumberger Simultaneous Production Logging Tool (PLT).

Completion Evaluation

– Continuous flow meter – Fullbore spinner

S p in n e r ro ta ti o n , rp s

Viscous and mechanical losses

µ increase Ideal response

Mechanical losses

(bearing friction, etc.)

ρ increase

v_th

0 2 4 6 8 10 0 40 80 120 160 200 240 280 320 Fluid velocity, ft/minute

S p in n e r s p e e d , rp s re v /s e c

(A) Continuous flowmeter

(small diameter) Ide al slo pe = 0 .05 rp s slo pe = 0 .040 rp s/(f t/m in) V f = 3 .5 f t/m in Gas at 1 4.7 psi slop e = 0.02 5 rp s/(ft /min ) Vf= 50 ft /min Wat er 0 2 4 6 8 10 0 40 80 120 160 200 240 280 Fluid velocity, ft/minute

S p in n e r s p e e d , rp s re v /s e c

(B) Fullbore continuous flowmeter

Gas under pre ssur e slop e = 0.0 40 r ps/(f t/m in) Vf= 12 ft /min Wat er s lop e = 0.04 3 rp s/(f t/m in) Vf= 3 ft /min

Electrical connection Lower bearing Upper bearing Magnet Pickup coil Spinner Schematic of Schlumberger/Sondex type continuous flowmeter spinner

Spinner

Basket Basket flowmeter opened

CCL Electronic cartridge Spinner section Packer spring Packer bag Pump Filter Packer spring Packer bag Pump Filter Packer tube Comumicatation CCL cartridge Electronic cartridge Flowmeter Water-cut meter Densimeter Fluid entrance port

Shut in three days Well Sketch Continuous Flowmeter, rps Temperature

0 20 40 40°C 60°C 80°C “F” “E” “D” “C” “B” “A”

Shut in one day

During injection Flowmeter before treatment 11.000 B/D Flowmeter after treatment 23.000 B/D

Review of Flowmeter Types

• Stationary

• Continuous

– In-situ calibration (takes

time but arguably more valid than a chart as it takes actual tool

characteristics into account)

– Medium to high

flow-rates. Poor sensitivity to low rates, especially in multi-phase flow – Interpretation becomes difficult in multi-phase flow, especially in inclined pipe – Point measurements – Lab-derived response chart

– Low to medium flow

rates. (pressure

differential across the sealing element induces leaks and eventually

moves the tool)

– Converging effect tends

to homogenize fluid mixture in relatively

narrow tool body - better interpretation in multi-phase flow.

Completion Evaluation

– Can be placed into the following two

categories:

Ê Gamma ray tools without

downhole ejectors for releasing radioactive material

Ê Gamma ray tools with downhole ejectors and multiple gamma ray detectors

First detector

10.5 seconds

Second detector

6 seconds Background

GR Lower Formation GR

Cable speed _Temperature

GR Upper _Tracker ejection

∆ Depth

Presumed path of annulus water 4900 4000 5000 5100 0 500 1000 Flow rate, B/D Ejector Near d e tect o r Far detec tor CCL 51.5” 59.0” A B C D E F G H I

Completion Evaluation

– Gradiomanometer tool

– Pressure-temperature tool – Nuclear fluid density tool

Transducer Upper Sensing Bellows Slotted Housing Floating Connection Tube Lower Sensing Bellows Bellows Expansion 38.9 32.0

8200 8300 8400 8500 0.7 0.8 0.9 1 1.1 1.2 Fluid density, GM/CC D e pt h, f e e t 5 1/2” Flowing Shut-in

8200 8300 8400 8500 1600 1800 2000 2200 Oscillator frequency, Hz D e pth, fe e t 5 1/2” Water Shut-in Oil O/W Contact

Shielding 2 Feet CS 137 Source Gamma ray detector Counter Fluid density instrument Gamma ray source

Completion Evaluation

• Temperature Tools

– Detection of gas production via the cooling

effect of expanding gas

– Qualitative evaluation of fluid flow indicated

by departures from the geothermal gradient

– Temperature information for PVT equations – Evaluation of fracture treatments

– Evaluation of mechanical integrity of a

Completion Evaluation

– Two types of noise logs

Ê Single frequency Ê Multiple frequency

Cement Evaluation

• Variable density log (VDL)

• Compensated cement bond log • Cement evaluation tools (CET)

Cement Evaluation

– The CBL, later combined with the

VDL waveform, has been for many years the primary way to evaluate cement quality. The principle of

measurement is to record the transit time and attenuation of an acoustic wave after propagation through the borehole fluid and casing wall.

Cement Evaluation

– A newer generation tool that is lighter

and more flexible for use in deviated holes. The principle of the

measurement consists of recording two sets of receiver amplitudes and computing their ratio. This ratio is then used to compute attenuation.

Cement Evaluation

– This tool evaluates the quality of the

cementation in eight directions with very fine vertical resolution.

Perforating

• Wireline Perforating Guns • Tubing Conveyed