Full text loading...
-
Probabilistic Interpretation of Microseismic Event Distributions
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
Validation experiments as well as theoretical arguments have shown that in the absence of pre-existing openings the true distribution of microseismic events is closely related to the extension of the fracture network generated by hydraulic stimulation. Due to the limited signal quality, sensor coverage and accuracy of the underlying velocity model the calculated apparent locations of the microseismic events will be different from the true event locations. Given a large number of events these random variations will lead to an inflation of the true underlying event distribution. One approach to discount this inflation effect are clustering or collapsing techniques. Typically these methodologies will use arbitrary rules to move the events within their uncertainty space to generate simpler distributions. The approach shown in this paper avoids such subjective rules and works directly with the probability density functions that represent the solution space for the event location. By using the cumulative probability function of all events the upward and downward fracture growth can be described probabilistically reflecting the true information content in the data. The results of this probabilistic interpretation can directly be used in probabilistic reservoir modeling and is an improvement over a deterministic approach that generates over-confidence in the interpretation.