Cased Hole Logging

Cased Hole Logging Dr. Ir. Dedy Kristanto, M.Sc

Cased Hole Logging • • • • •

Formation Evaluation 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 • • • •

Old wells Gravel-pack monitoring Channeling behind casing In-situ petrophysical properties

Formation Evaluation Logs for cased hole formation evaluation – Gamma ray – NGS log – Neutron log – Sonic log – Thermal decay time log – Gamma ray spectrometry tool

NEAR & FAR COUNTS

SIGMA GR RATIO

TDT ANALYSIS

Completion Evaluation Production logging applications – Well performance – Well problems – Well testing – Single and multi phase flow – Flow anomalies

Completion Evaluation • Evaluating completion efficiency • Detecting mechanical problems, breakthrough, coning • Providing guidance for workovers, enhanced recovery projects • Evaluating stimulation treatment effectiveness • Monitoring and profiling of production and injection

Completion Evaluation • Detecting thief zones, channeled cement • Single layer and multiple layer well test evaluation • Determining reservoir characteristics • Identifying reservoir boundaries for field development

Completion Evaluation Production logging tools – Spinner flow meters – Radioactive tracer tools – Fluid density tools – Nuclear fluid density tools – Temperature tools – Noise tools

Gamma Ray 0

9000

2

API Caliper Inches

CAL

Pressure

500 7 0

4000 PSIA 4200 Temperature Density Total Flow BPD 28000 0.2 °F g/cm3 245 0 1.2 240

Diphasic Analysis

Total Flow 0

Flow Rates BPD 28000 0.2

Temperature 245 °F

28000 240 Density g/cm3 1.2

Flowing

100%

9100

Shut-in

75%

PLT GR 9200

65%

9300

OH GR

25% Flowing

9400 Shut-in

9500

Cable head Weights

Weights

Thru-tubing guide (Centralizer) Collar locator

PCM/CCL Telemetry

Telemetry cartridge, including GR detector

10” motorized centralizer

Caliper

Quartz pressure gauge

Gamma ray

Fluid density Temperature

In-line flowmeter Centralizer Thermometer/ Strain-gauge Gradiomanometer

Pressure 10” Bow spring centralizer Continuous spinner flowmeter

Fullbore flowmeter

The Schlumberger Simultaneous Production Logging Tool (PLT).

Atlas Wireline’s SPL tool.

Completion Evaluation • Spinner Tools – Continuous flow meter – Fullbore spinner – Inflatable diverter

Spinner rotation, rps

Ideal response

ρ increase µ increase

Mechanical losses (bearing friction, etc.)

Viscous and mechanical losses

vth Fluid velocity, vf

W at e V r sl f = op G 3 as ft / e = m 0. in 04 sl und o 3 V pe er rp f = pr s/ = 12 0 es (f t /m ft/ .04 su in m 0 re ) in rp s/ (ft /m in )

10

lop

6

slo

2

f

s p i r ps 25 7 4. 0.0 in 1 at pe = ft/m s 0 Ga slo = 5 Vf V

W

at e

r

4

t / (f

/m

) in

Spinner speed, rps rev/sec

p ps = e= 3.5 0. ft/ 040 m in rps /( f t/m

e=

0. 0 5r

8

Ide al s

Spinner speed, rps rev/sec

in

)

10

8

6

4

2

0

0 0

40

80

120

160

200

240

Fluid velocity, ft/minute

(A) Continuous flowmeter (small diameter)

280

320

0

40

80

120

160

200

240

280

Fluid velocity, ft/minute

(B) Fullbore continuous flowmeter

Electrical connection

Upper bearing Magnet Pickup coil

Spinner

Lower bearing

Schematic of Schlumberger/Sondex type continuous flowmeter spinner

Peco type spinner flowmeter

Spinner

Basket Basket flowmeter opened in production well

CCL Electronic cartridge

Comumicatation CCL cartridge Electronic cartridge

Spinner section

Flowmeter Water-cut meter

Packer spring

Densimeter

Packer spring Packer tube

Packer bag

Packer bag Pump Filter

Fluid entrance port

Pump Filter

Well Sketch

Continuous Flowmeter, rps 0

20

40

Temperature 40°C

60°C

80°C

“F”

“E”

“D”

“C”

“B”

“A”

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

Shut in one day Shut in three days During injection

Review of Flowmeter Types •

Continuous – In-situ calibration (takes time but arguably more valid than a chart as it takes actual tool characteristics into account) – Medium to high flowrates. Poor sensitivity to low rates, especially in multi-phase flow – Interpretation becomes difficult in multi-phase flow, especially in inclined pipe

•

Stationary – 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 multiphase flow.

Completion Evaluation • Radioactive Tracer Tools – 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

Background

First detector 10.5 seconds

Second detector

6 seconds

Formation GR Cable speed CCL

Temperature GR Lower GR Upper

Tracker ejection ∆ Depth

Flow rate, B/D

4900 Presumed path of annulus water

A

5000

B C D E F G H I

Near detector 51.5”

Ejector

1000

CCL

500

Far detector 59.0”

4000

0

5100

Completion Evaluation • Fluid Density Tools – Gradiomanometer tool – Pressure-temperature tool – Nuclear fluid density tool

32.0

Transducer

Upper Sensing Bellows Slotted Housing Floating Connection Tube

38.9

Lower Sensing Bellows

Expansion Bellows

8200

Flowing

Shut-in Depth, feet

8300

8400

5 1/2” 8500 0.7

0.8

0.9

1

1.1

Fluid density, GM/CC

1.2

Oil

Water

Depth, feet

8300

O/W Contact

Shut-in

8200

8400

5 1/2” 8500 1600

1800

2000

Oscillator frequency, Hz

2200

Gamma ray source

Fluid density instrument Counter

Sampling channel

2 Feet

Gamma ray detector

Shielding

CS 137 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

Completion Evaluation • Noise Tools – Two types of noise logs Ê Single frequency Ê Multiple frequency

Cement Evaluation • • • •

Cement bond log (CBL) Variable density log (VDL) Compensated cement bond log Cement evaluation tools (CET)

Cement Evaluation • The cement bond log (CBL) – 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 • Compensated Cement Bond Tool – 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 • Cement Evaluation Tool – This tool evaluates the quality of the cementation in eight directions with very fine vertical resolution.

Perforating • Shaped Charges • Wireline Perforating Guns • Tubing Conveyed Perforating Guns