We provide Full-Wave Location passive seismic services to determine and manage risks and opportunities associated with faults, fractures and fluid injection. Using technical expertise, advanced passive seismic methodology, sensory equipment, computer simulations and quantitative methods, we identify, evaluate and resolve your subsurface characterisation challenges.

What is FWL?

FWL, or Full-Wave Location, is a geophysical method applied to microseismic data to accurately detect fluid movement and other causes of microseismic activity in the subsurface. It pinpoints the location and type of microseismic events by determining the events’ seismic moment tensor in the presence of strongly correlated noise. This technique has proven a valuable method for facilitating better reservoir management, improving hydrocarbon recovery, monitoring fluid injection operations and establishing potential areas of concern throughout the operational cycle. What is FWL? Watch the “Webinar part 3: Full wave location technology with case studies

Theory

Monitoring of microseismic activity at the surface is a well-known technique in the seismic acquisition community. It is based on phased array antenna technology originally developed for use in military radars. The most common method applied to the technique is the diffraction stack method of seismic migration that uses the integral form of the wave equation. Typically, microseismic events can’t be identified on the raw data set due to the extremely low magnitude of the event. TenzorGEO uses highly sensitive, high grade sensors to detect seismic impulses which are several times lower than the level of surface noises.

The waveform of impulses which arrive at the sensor from a certain point in the geological medium are derived with the use of numerical simulation. The numerical simulation does not use any approximations or estimations, all the existing waves are absolutely determined (P, S, R and others). TenzorGEO locate seismic events based on a maximum likelihood method. This is a method of estimating the parameters of a statistical model and finding the parameter values that maximise the likelihood of making the observations in the specific setting, given the parameters. Solving the problem of locating microseismic events requires a very accurate model of the geological medium in question, however, a single 2D seismic velocity model does not present a sufficient and precise result. To counter this, TenzorGEO asks the operator to provide additional information, such as geological models with a specified standard of  accuracy that incorporate data from structural seismic models, vertical seismic profiles (VSP) data and sonic logs.

The FWL and maximum likelihood method is based on the estimation of seismic tensor components. For this, it is necessary to have awareness of the ‘useful signal’ (simulated responses from deep source). A ‘useful signal’ is a full-wave process registered on three component sensors located at the surface. The responses are calculated by 3D numerical simulation of wave processes in viscoelastic media. The numerical model is created using information from structural maps and vertical seismic profile data.

The source of the Full-Wave Location process is the force applied to the nodes around the point of visualisation in directions determined by components of the seismic moment tensor. This approach is the optimum way to  find and identify the type of event and offers further insight into the characteristics of the event in case a low signal-noise ratio is observed at the receiving channels.

Processing and interpretation

The data collected in the field must be processed, interpreted and presented in a user-friendly way. It is at this final stage that TenzorGEO can fully utilise the leverage of its extensive experience in geosciences, engineering and computer programming to provide an accurate report of the target area.

The main issue regarding microseismic monitoring is the high risk of contaminant noise interfering with the recording of data. This is derived from sources on the surface such as sea waves, passing ships, drilling equipment, etc. At TenzorGEO, we eliminate sources of noise during the data pre-processing stage using the optimisation method of quasi-harmonic noise filtering. Applying the method of maximum likelihood, signals with a high level of surface noise are automatically de-prioritised during the assessment of the most likely amplitude of microseismic event sources.

Processing and interpretation of FWL data includes the following steps:

  • initial static and relief corrections
  • identification of microseismic activity zones based on microseismic event source location
  • production of maps and models displaying the development of microseismic activity zones in the target area

Application

Natural fractures network mapping

As microseismic events occur mostly on pre-existing fractures or faults, the computation of their location provides a way of delineating active faults. Therefore, the Full-Wave Location technology helps to identify the geometry and position of these faults and to determine the active fault network within the reservoir, assuming a sufficient number of microseismic events have been recorded over a long period of time. Being informed about the active fracturing significantly boosts hydraulic fracturing operations, optimises field development, enhances decision making on optimal direction of horizontal wellbores, etc.

CO2 Injection

FWL technology is used for monitoring of CO2 injection-induced microseismic activity. This information is key to maintaining reservoir integrity and identifying any potential areas of concern such as leakage of CO2 from the target storage area

Identification of anomalous objects in geological media

By incorporating Full-Wave Location technology into the acquisition plan, the operator can improve the efficiency and safety of technological operations during the drilling, workover, well abandonment and monitoring of abandoned wells

Fracture Mapping

Deployment of the Full-Wave Location technology can be utilised to map zones of active natural fracking. Mapping areas of high microseismic activity and pinpointing fracture direction can aid in identifying axial lines of predicted faults. Such maps can be used by operators to improve reservoir management or applied in mining operations to reduce the risk of rock collapse associated with loose and fractured zones

Advantages

Advantages of Full-Wave Location technology:

  • The technology requires no additional infrastructure such as wells and downhole sensors. Field surveys are conducted from the surface using highly sensitive broadband seismometers.
  • 3-component event location using full form of wave process is carried out which contains all wave types.
  • The processing method automatically filters contaminate noise out of assessment, increasing the reliability of results.
  • Retrieving of seismic moment tensor and location of seismic events.
  • The implementation of the maximum likelihood method allows microseismic events to be detected even when the signal / noise ratio at the receiving channels is equal to 1/100.
  • Better prediction of fracture propagation pattern to inform engineers on the optimal well design and direction for appraisal, injection and production wells.
  • Improved engineering and mechanical control of the reservoir to maximise hydraulic fracturing impact on the production.
  • Better understanding of the fluid injection impact on the reservoir and precise determination of fluid migration paths.
  • Drilling cost optimisation and reduction in the number of wells required, thus reduces the overhead a client is subject to.

Case Studies

The images above show the results of a natural active fracture network mapping study within a mine. Knowledge of active fracturing can be used to predict the risks of collapses during operations. As microseismic events occur mostly on pre-existing fractures or faults, the computation of their location provides a way of delineating active faults. The results above show both the identification of fractures as well as their respective directions

The model and graphs above show the results from a monitoring operation in an area utilising hydraulic fracturing for the purpose of enhancing hydrocarbon production. The analysis of microseismic events originated from hydraulic fracturing was able to denote the events location and pinpoint the seismic moment sensor, making it possible to identify the directions of fracture propagation

DR ROY BITRUS, PhD

DIRECTOR OF SALES

suitable

Cases

Previous
Next

Talk to your expert

Anti-spam reCAPTCHA Privacy and Terms of Service

DR ROY BITRUS, PHD

DIRECTOR OF SALES

MUTUAL NON-DISCLOSURE AGREEMENT

THIS AGREEMENT BETWEEN:

1. Tenzor Geo Ltd, a Company registered in Scotland with Company Number SC587661 and having its registered office at 13 Queen’s Road, Aberdeen, AB15 4YL (hereafter Tenzor Geo); and

2. [Your Company Name] of [Your Company Address] (hereafter Partner).

Tenzor Geo and Partner agree as follows:

Affiliate means in relation to either party any entity that from time to time, directly or indirectly controls, is controlled by, or is under common control with that party, or that is a successor (including, without limitation, by change of name, dissolution, merger, consolidation, reorganization, sale or other disposition) to any such entity or its business and assets. An entity will be deemed to control another entity if it has the power to direct or cause the direction of the management or policies of such entity, whether through the ownership of voting securities, by contract or otherwise.

Business Purpose means discussions relating to Tenzor Geo introduction, including but not limited to its structure, technology, processes, clients, counterparties, project, plans, etc. Group means each contracting party and its respective advisers, agents and representatives from time to time and its Affiliates and their respective advisers, agents and representatives from time to time.

Information means information in any form (including, without limitation, methodology, software and computer outputs) which is not excluded under clause 4 below, whether written or oral, of a business, financial or technical nature which is marked or otherwise indicated as being or is, or ought reasonably to be, known to be confidential and which is disclosed by one party to this Agreement (the Disclosing Party) or any member of its Group to the other party (the Receiving Party) or any member of its Group or otherwise come to its attention during the parties’ involvement in the Business Purpose. Information includes information relating to the involvement of either party’s Group in the Business Purpose.

1. The Receiving Party agrees:

(a) to hold the Information in confidence and, not without the Disclosing Party’s prior written consent, to disclose any part of it, to any person other than those directly concerned with the Business Purpose and whose knowledge of such Information is essential for such purposes. The Receiving Party will ensure that those persons comply with the obligations imposed on the Receiving Party under this Agreement. The Receiving Party shall be liable for such person’s default;

(b) not, without the Disclosing Party’s prior written consent, to use the Information for any purpose other than the Business Purpose;

(c) to delete from any device containing any Information and/or return to the Disclosing Party upon demand the Information except for one copy of such Information as is required to be retained by law, regulation, professional standards or reasonable business practice by a member of Receiving Party’s Group; and

(d) to use reasonable endeavours to provide the Disclosing Party with prompt notice if any member of the Receiving Party’s Group becomes legally compelled to disclose any of the Information, so that the Disclosing Party may seek a protective order or other appropriate remedy. If such order or remedy is not available in time, the obligation of confidentiality shall be waived to the extent necessary to comply with the law.

2. The Receiving Party agrees that no right or licence is granted to the Receiving Party’s Group in relation to any part of the Disclosing Party’s Information.

3. Neither party nor any member of its respective Group warrants the accuracy or completeness of the Information. Accordingly, neither party’s Group shall have any liability to the other resulting from the use of the Information, save in respect of liability arising from fraudulent misrepresentation.

4. Clause 1 does not apply to Information which:

(a) at the time of disclosure is, or subsequently through no fault of the Receiving Party’s Group becomes, generally available to the public;

(b) becomes rightfully known to the Receiving Party’s Group through a third party with no obligation of confidentiality;

(c) the Receiving Party is able to prove was lawfully in the possession of the Receiving Party’s Group prior to such disclosure; or

(d) is independently developed by the Receiving Party’s Group.

5. The obligations in this Agreement shall be binding on both parties for so long as the Information retains commercial value.

6. Each of the parties acknowledges that a person with rights under this Agreement may be irreparably harmed by any breach of its terms and that financial remedies alone may not necessarily be adequate. Accordingly, a person bringing a claim under this Agreement may be entitled to injunctive or other equitable relief for any threatened or actual breach of its terms.

7. Members of the parties’ respective Groups shall have the right under the Contracts (Rights of Third Parties) Act 1999 (the Act) to enforce the terms of this Agreement. The Act shall not affect any right or remedy available to any member of either party’s Group apart from the Act.

8. This Agreement is made by the Receiving Party on its own behalf and as agent for each member of its Group.

9. This Agreement will be governed by, and construed in accordance with, English law. Each party irrevocably submits to the jurisdiction of the English courts

Partner

Authorised Signatory: [your-name] verified via email

 

Tenzor Geo Ltd

Authorised Signatory: Ivan Starostin