Introduction to

Wave Propagation Resistivity (WPR)

Why Resistivity?

• Primary evaluation measurement– Correlation

– Resistivity based real-time Pore Pressure trend analysis

– Hydrocarbon zone ‘Quick-Look’

– Oil/Gas-Water contact– Oil/Gas-Water contact

– Geosteering

• Uses Resistivity contrast between formations or

zones

• Distance to bed calculation

• Optimize borehole position in reservoir

2

Fundamentals

Gamma Ray – Lithology and reservoir rock ID

Resistivity – Fluids in the rock oil/gas/water

3

Resistivity – Fluids in the rock oil/gas/water

Gamma Ray Logging

• Measure of the rock’s natural gamma ray emissions to distinguish reservoir from non reservoir rock

• Isotopes of K, U, Th emit gamma rays

Sands

Shales• Generally – Reservoir rocks

(Sandstone (SiO2), Limestone (CaCo3)) have low amounts of K, U, Th while traditional non-reservoir rocks (Shales) have higher amounts, particularly K

http://www.kgs.ku.edu/Dakota/vol1/petro/petro03.htm

Shales

More information is often required…

What is needed next?

Roadmap for Resistivity

• Customer– Scope of Work

• Define and confirm customer’s needs and applications

• Tool size, hole size, logging section requirements, and mud type

• Data requirements – Real-Time, Memory

• Equipment– Lead time considerations

– Downhole tools & back-ups w/spares

– Surface kit – Current computers and software

• Rm meter, cabling, test gear

• Plotters, paper, and ink

5

Roadmap for Resistivity

• Develop Support Personnel– Training

• WPR School – In-house intro and detailed instruction w/ hands-on

practice

• Coordinators – Ops coordinators need to understand

configuration, air hang QC, operation and log interpretation

6

configuration, air hang QC, operation and log interpretation

• Onsite FSE – SW operation, tool configuration and rig up, air

hang acquisition and evaluation, data dump and processing, log

presentation and base level interpretation

• R&M - Maintenance technician training, maintenance levels and

schedules

Roadmap for Resistivity

• Operations– Prewell planning – Define deliverables daily updates, log scales

and types, data transmission in real time with optimized rates,

digital data formats and end deliverables

– PreSpud – Confirm configurations, objectives and data flow

– Execution – Perform LWD operation

7

– Execution – Perform LWD operation

• People and Tools to the rig on time

• Data delivered as planned

• First well may require APS FSE assistance

Roadmap for Resistivity

• Closing the Loop

– Final Log preparation, review, and acceptance QC

– End of Well Reports and digital deliveries

+ ▲ Objectives met for the customer?+ ▲ Objectives met for the customer?

• Lessons learned - Improvements to be made

8

WPR Project’s Conservative

Design Philosophy

• Use field-proven design concepts; team

incorporated experience from four previous

propagation resistivity designs

• Use field-proven materials and technologies

• Re-use circuit designs and software from

other APS products wherever possible

WPR Basic Requirements

• Safety: No hands under metal

• Industry-standard frequencies and antenna

spacings

• All components 31 ft. (9.5 m) or less• All components 31 ft. (9.5 m) or less

• Field-replaceable batteries (in separate collar)

• Easy to make-up and test @ shop and rig

• Operationally robust by design (TMC)

WPR Basic Specifications

• Nominal sizes: 3.5 in. (89 mm), 4.75 in. (121 mm), 6.75 in. (171 mm), 8.0 in. (203 mm)

• Interfaces to APS SureShot™ MWD system via RS-485 interface

• Two operating frequencies: 2 MHz and 400 kHz

• Power: 10 W operating; 2 W quiescent

• Memory: 32 MB

• Runs on 2x – 3x 36v batteries or 1x turbine/alternator with 0x – 2x batteries

WPR Basic Specifications

• LWD and standalone “Measurement After Drilling” (MAD) modes

• Intrinsically safe RS-485-like test/programming/data dump porttest/programming/data dump port

• PWD option

• Max. temperature: 150°°°° C (175°°°° C option)

• Max. pressure: 20 kpsi (1,361 atm; 137.9 MPa)

WPR™ Theory -

Electromagnetic Spectrum

http://zebu.uoregon.edu/~imamura/122/images/electromagn

etic-spectrum.jpg13

WL 20 kHz, WPR 400 kHz and 2 MHz

T R1 R2

Amplitude Ratio

WPR™ －－－－Theory

Phase Difference

Phase Difference & Amplitude Ratio measurements are proportional to formation

conductivity and insensitive to borehole environment

WPR Compensation Method

• Symmetrical antenna design provide for optimal compensation

• Compensation improves

T2

T1

• Compensation improves accuracy

• Centrally located receiver antennas eliminate time lapses between measurements

T4

R2

T3

R1

SureShot ™ MWD

DG-MWD / LWD Platform

SureShot DG + WPR System