A time-lapse seismic wavefield monitoring system for a formation includes at least one seismic wavefield source and at least one seismic wavefield sensor to collect seismic wavefield survey data corresponding to the formation in response to an emission from the at least one seismic wavefield source. The seismic wavefield survey data includes first seismic wavefield data collected at a first time and second seismic wavefield data collected at a second time. The time-lapse seismic wavefield monitoring system also includes a processing unit in communication with the at least one seismic wavefield sensor. The processing unit determines time-lapsed seismic wavefield data based on the first seismic wavefield data and the second seismic wavefield data, and performs an analysis of the time-lapsed seismic wavefield data to determine an attribute change in an earth model.

A method for modeling a subsurface volume using time-lapse data includes receiving a baseline seismic dataset, a baseline property model, a monitoring seismic dataset. and a monitoring property model. sorting the baseline seismic dataset and the monitoring seismic dataset into respective common gathers, representing offset, time, and depth point, extracting signal data for a range of depth points for the baseline dataset and a signal data for a corresponding range of depth points for the monitoring seismic dataset, predicting a property model change based at least in part on the signal data for the range of depth points of the baseline seismic dataset and the monitoring seismic dataset, using a machine learning model, and generating a property model representing a subsurface volume based at least in part on the property model change predicted using the machine learning model.

A method for evaluating a wellbore treatment includes inducing an acoustic wave in the wellbore prior to treatment. Acoustic energy propagating as pressure waves in the wellbore is detected. A formation in fluid communication with the wellbore is treated. The inducing an acoustic wave and detecting acoustic energy are repeated. A characteristic of the treatment is determined based on differences between the detected acoustic energy prior to the treating and at the end of the treating. In some embodiments, the observed differences are then also compared to differences observed in prior treatment stages to assess benefit of changes to treatment design. In some embodiments, the treatment design parameters are continuously iterated, adjusted, and improved to maximize the contribution to production of all subsequent stages in same or any other well.

Methods are provided for tracking carbon dioxide (CO.sub.2) migration in a hydrocarbon-bearing reservoir located under a cap rock in a formation. In one embodiment, at least one seismic source and a plurality of receivers are located in spaced boreholes in the formation with the sources and receivers located near or at the reservoir so that direct paths from the sources to the receivers extend through the reservoir. CO.sub.2 is injected from the borehole containing the seismic sources into the reservoir, and the sources are activated multiple times over days and seismic signals are detected at the receivers. From the detected signals, time-lapse travel delay of direct arrivals of the signals are found and are used to track CO.sub.2 in the reservoir as a function of time. In another embodiment, the sources and receivers are located above the reservoir, and reflected waves are utilized to track the CO.sub.2.

A method is described for time-lapse seismic imaging that may include detecting moire patterns in seismic images generated from time-lapse seismic data and identifying geologic features based on the moire patterns. The method may be executed by a computer system.

A method for developing or maintaining a subterranean field includes: parameterizing seismic wave records for each identified seismic event to provide a parameter describing each seismic wave record used to identify each seismic event; generating a reference seismic event data base having the identified seismic events and the parameter; calculating a similarity value for new received seismic wave records with respect to each seismic event in the reference seismic event data base using the corresponding parameter to provide a plurality of similarity values; identifying a maximum similarity value from any of the similarity values in the plurality of similarity values that meets or exceeds a similarity threshold value; identifying a new seismic event at a location of the seismic event in the reference seismic event data base corresponding to the maximum similarity value; and modifying operation of subterranean field-related equipment in response to identifying the new seismic event.

A method and system for identifying reservoir drainage patterns from microseismic data for illustrating flow paths towards ports. The method includes: determining moment tensor data for each of a plurality of microseismic events in the reservoir; inferring crack formation data in the reservoir in dependence on the moment tensor data; and calculating stream lines that represent predicted flow of fluids through the reservoir in dependence on the inferred crack formation data.

The present disclosure describes a computer-implemented method that includes: receiving a seismic dataset of a surveyed subsurface of a reservoir, the seismic dataset comprising observed pressure and production data of the reservoir as well as a set of geological and geo-mechanical parameters representing physical features of the surveyed subsurface; generating multiple realizations of a discrete fracture network (DFN) based on a subset of the set of geological and geo-mechanical parameters; selecting, from the multiple realizations, one or more realizations based on a parameter with a value under a 10% quantile of a full range of likely values; performing a forward simulation for the reservoir based on the selected one or more realizations and the observed pressure and production data; determining that a misfit of the forward simulation is below a threshold based on evaluating an objective function; and producing a model of the reservoir based on the forward simulation.

A method of mapping reservoir fluid in a mature field includes identifying a region of interest within a hydrocarbon field, drilling a plurality of production wells through the region of interest, and collecting mud gas data as each production well is drilled. This mud gas data is used to generate a reservoir fluid property log, such as gas-oil ratio log, along a length of each of the production wells, which is in turn used to generate a refined model based on the 4D seismic data. The refined model permits better reservoir fluid mapping and has an improved vertical resolution at the region of interest than the first model of the field.

The invention relates to a method for processing seismic images containing a reference trace and a control trace. During said method, a reference level and a recording level are defined. Then, the control trace is transformed on the reference level by means of a velocity model. A portion of the reference trace including the recording level is transformed by means of a current velocity model. A portion of the transformed control trace including the recording level is corrected by means of the current velocity model. Finally, an optimised current velocity model is determined.