Recent new capability
Elemental Analysis and Chemostratigraphy Services
Ellington & Associates, Inc. and Chemostrat Inc. have formed and alliance to provide elemental analysis and chemostratigraphy from a base in Houston, Texas.
The Houston based lab is the first commercial XRF elemental service based in the U.S.
more..
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Overview
 Based on numerical solution of Maxwell equations.
Greatly improves on current state of EM MWD theory.
Computes signal attenuation based on media properties,
signal frequency, etc.
Allows selection of optimal signal strength and frequency.
Determines electromagnetic field distribution and currents
in surrounding media and along drill string.
Calculates impedance of the entire system.
Determines the optimal EM transmitter gap size.
Allows determination of the most optimal drilling fluid.
Determines optimal parameters of the receiver (including differential receivers).
Accounts for effect of different casing and drillstring configurations.
Accounts for finite resistance and permeability of metal and drillstring joints.
Applications
Designing EM MWD systems.
Interpreting field measurements.
Great sales and marketing tool.
Vertical, directional and horizontal drilling.
Onshore and offshore wells.
Helps understand physical phenomena in the system.
Demonstrated good matching with the field measurements.
Uniqueness
Significant improvements on the current state of EM MWD
theory.
Set up all aspects of drill string, casing and transmitter
geometry.
Specify multiple formations with different resistivity and
permeability values.
Choose various parameters of the drilling fluid.
Pick transmitter signal of desired strength, form and
frequency.
Takes into account the finite resistivity and permeability of
drill string and casing and resistivity of joints.
Example
Screenshots below have been obtained for the following configuration:
Vertical well H=2500 m, ID=0.199 m
Casing H=700 m, ID=0.199 m, OD=0.219 m
Drill string H=2000 m, ID=0.121 m, OD=0.14 m
Transmitter gap at depth H=1800 m, gap size=0.04m
Signal strength 3 Volt, frequency 10 Hz
Signal form factor 0.5 chosen to approximate real-world source with a sine wave
Surface antenna L=200 m away from the well
Drilling fluid Ro=50 Ohm*m, Mu=1.25E-6
Four rock layers:
1. Ro=20 Ohm*m, Mu=1.25E-6, H=609 m
2. Ro=10 Ohm*m, Mu=1.25E-6, H=914 m
3. Ro=15 Ohm*m, Mu=1.25E-6, H=1828 m
4. Ro=25 Ohm*m, Mu=1.25E-6
Well geometry
Casing and drill string are selectable from a range of
pre-determined sizes.
English/metric system switch.
Changes visually demonstrated on the schema in real time.
Setup Source and Receiver
Switch between current and voltage source mode.
Signal form factor controls sharpness of signal front.
Receiver antenna length.
Stop condition allows researching transitional processes.
Setup Media
Drilling fluid resistivity and permeability.
Configure up to 10 rock or formation layers.
Switch selects which layer’s data is edited.
For each layer set up: depth, resistivity, magnetic
permeability.
Results
This page has large buttons that display results of the
calculation.
Each button includes a preview image to indicate the kind of
graph this button opens.
Current Chart
Current Distribution in the Well After Specified Time Period
Signal Chart
Transmitted and Received Signals Vs. Time
Red-transmitted signal.
Blue-received signal.
Allows visualization of:
Signal form
Strength
Phase shift
Transitional processes
Signal dispersion
Electric Field
2D Electrical Field Distribution Chart: E(r,z)
Square in the top-roght corner contains main calculation results.
Arrow direction shows direction of current.
Color shows field intensity.
Note that besides current on electrodes simulator generates
turbulent (Fucoe) currents.
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