The depths of the Earth are in a continual stress-strain state. Every kind of impact on the geological environment, whether natural or man-made, sets off various activities in the strata. These are accompanied by energy emissions and wave processes that reach out to the ground surface.
By capturing these microseismic emissions, valuable geophysical data can be collected and interpreted to assess the stress state of the Earth’s crust, detecting the spatial position of its sources and the type of deformation that caused their formation.
Since microseismic events occur mostly on pre-existing fractures or faults, the computation of their location provides a way of delineating active faults. It is, therefore, possible to obtain the geometry and position of these faults and to determine the active fault network in the reservoir, from a sufficient number of microseismic events recorded over a period of 3-4 weeks. TenzorGEO uses Full-Wave Location technology to perform this type of survey. The preliminary knowledge about active fractures network helps operators to:
- design effective hydraulic fracturing operation
- optimise field development
- select optimal position and direction of horizontal or vertical wells
- predict the risks of collapses during mining operations
The survey is completed from the surface without any disturbance to the ongoing operations in the neighbouring wells apart from initial location system calibration from one of the wells, making it much cheaper than alternative monitoring methods from the wellbore. Full-Wave Location technology has high noise resistance and sensitivity, which allows it to be used in areas with high level of man-made noise.
The results obtained during the microseismic monitoring show zones of natural active fracturing and allow to assess the microseismic activity in an investigated volume. They highlight areas with the highest microseismic activity, build a map of the dominant fracture directions and estimate the position of the weakened zones associated with active fracturing.
Over the last decade, Full-Wave Location technology was successfully applied during natural active fracture network mapping for leading Eurasian and Indian operators. For more information, please see our Case Studies section.
DR ROY BITRUS, PhD
DIRECTOR OF SALES