About MTEM

Like all great ideas, the MTEM® method is remarkably simple. By suddenly reversing the voltage between two electrodes a step, or transient, is put into the earth, and the earth's response is recorded between receiver electrodes. By deconvolving (removing) the system (source and receiver) response from the data, an accurate impulse response of the earth is produced. Proprietary processing produces a resistivity cross-section of the earth. High resistors indicate hydrocarbons.

Land acquisition

A series of source and receiver electrodes is pushed into the ground at surveyed positions. The source is connected to two source electrodes and pairs of receiver electrodes are connected to proprietary MTEM acquisition units. The source is fired, and the voltage across the pairs of receiver electrodes recorded. A key element of the patented technique is that the source and receiver performance for every shot is measured and that recording is used as the first step in processing.

As soon as the data is recorded, the voltage is reversed, producing the next MTEM transient, and another shot is acquired. Proprietary software calculates the signal to noise ratio while the data is collected, allowing the operator to know when sufficient data for that layout has been collected. The source and receiver electrodes are then moved down the line building up the subsurface picture.

Reciprocity allows the technique to be used in obstructed areas allowing us to overcome obstacles including power lines, well heads, rivers and buildings. Real Time Appraisal provides a first look at the reservoir in the field within 24 hours of data collection.

After noise removal, deconvolution, stacking and conversion to log-time, MTEM data looks a lot like seismic data. By picking the arrival from the subsurface, in a similar way to velocity picking in seismic, the travel-time for each source-receiver pair is determined.

A simple mapping produces a plot of resistivity against depth which allows the client to confirm the presence or absence of resistors immediately. State of the art inversion methods, using the travel times and absolute amplitudes, are used at MTEM headquarters to produce more advanced products.

The MTEM method provides much greater confidence in the processed result than the conventional techniques because no preconceived model is required. The MTEM processing route allows the client to see the reservoir through the data.

Marine acquistion
The same technique can be used in a marine environment. The fundamental science and approach are the same as on land but a number of alterations and additions are needed to allow for the different conditions and the operational efficiency required for marine operations.

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Technical Articles

 Overview (188Kb)
 Method (164Kb)
 Applications (170Kb)
 R-Land (196Kb)
 R-Marine (163Kb)
 R-Solutions (KB)