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AssigneesInstitut Francais du Petrole, Gaz de France (Service National)
InventorJean-Pierre Deflandre
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The invention is a method for facilitating discrimination and identification of seismic or microseismic events by means of permanent pickups in an underground zone under development. The method comprises permanent installation of, in one or more wells, elastic wave receivers, geophones and hydrophones leaving the wells clear for development of the zone, at least one reference pickup with direct acoustic coupling with the technical zone development equipment (pickup pressed against a production string for example) for detection of events directly connected with the operation of the wells (valve opening and closure, etc.), acquisition of the signals coming from the various receivers and from each reference pickup in response to the waves received, and comparative analysis of the signals associated with the receivers and with the reference pickup(s), in order to classify the records into different families according to whether the events in the underground zone are independent of the events detected by each reference pickup or depend directly or indirectly thereon, and for each family, application of specific processings. The method can be used for long-term monitoring of fluid production of storage reservoirs, such as hydrocarbons, various waste products, geothermics, etc.
A method for facilitating identification of seismic or microseismic events relative to the development of an underground zone, comprising coupling permanent receivers with a wall of at least one well for sensing first elastic waves coming from the underground zone in response to the seismic or microseismic events, positioning at least one reference pickup with a direct acoustic coupling with elements of equipment used for the technical development of the zone for sensing parasitic elastic waves directly generated by the technical development, acquiring and recording first signals sensed by the permanent receivers and second signals sensed by each reference pickup and comparatively analyzing the first signals sensed by the permanent receivers and signals sensed by each reference pickup, sorting the recorded signals into different families according to whether the first signals only depend on seismic or microseismic events in the underground zone or directly or indirectly depend on parasitic elastic waves directly generated by the technical development.
A system for facilitating identification of seismic or microseismic events in an underground zone under development, comprising permanent receivers for sensing elastic waves coupled with the walls of at least one well, at least one reference pickup with a direct acoustic coupling with elements of an equipment used for the technical development of the underground zone for sensing parasitic elastic waves directly generated by the technical development, a device for acquiring and recording first signals sensed by the permanent receivers and second signals sensed by each reference pickup, a transmission device for transmitting the first and second signals to ground and an acquisition and processing unit comprising a computation device programmed for comparatively analyzing the first signals sensed by the receivers and signals sensed by each reference pickup, which sorts the recorded signals into different families according to whether the first signals only depend on seismic or microseismic events in the underground zone or directly or indirectly depend on parasitic elastic waves directly generated by the technical development.
Dependencies are inferred from the claim text.