Successful interpretation of seismic data

Paul Boughton

Powerful software solutions are essential to interpret seismic data successfully. Here we look at what the major players have got. Sean Ottewell reports.

Landmark's SeisWorks 3D software provides innovative 3D viewing and interpretation capabilities and easy-to-use interpretation productivity tools to support and enhance horizon and fault interpretation. The company says that it is the industry standard for 3D seismic data analysis and interpretation. With SeisWorks 3D software, interpreters can work with a 2D project and multiple 3D projects concurrently for great interpretation flexibility. According to Landmark, the SeisWorks product family is the oil and gas industry's leading integrated seismic interpretation and analysis software package, delivering core interpretation functionality to seismic interpreters. The products set the performance measure for the management, access, display, and interpretation of large-survey data.

Through Landmark's OpenWorks data management environment, SeisWorks software offers interpreters cross-discipline data access and integration with a powerful suite of innovative technologies, supporting advanced seismic interpretation workflows.

One major benefit is higher productivity. Interpreters can finish their work quickly with these basic day-to-day interpretation tools and automated tools and processes. SeisWorks 3D tools are easy to use and easy to control, and make it easy to select data. Interpreters never waste valuable time copying, transferring and reformatting data between applications because SeisWorks 3D software is integrated with Landmark's classic products.[Page Break]

In addition, SeisWorks analysis and interpretation tools, combined with integrated applications for poststack processing and attribute analysis, lead to an improved understanding of the subsurface and more accurate interpretations.

The SeisWorks family helps geoscientists understand complex reservoir settings before a well is ever drilled. By examining, testing, and comparing alternative interpretation scenarios with relevant geophysical and geological data, more accurate interpretations and lower prospect risk are possible. The result is better decisions, higher success ratios, lower finding costs and fewer dry holes.

Its 3D tools also allow users to develop a rich, searchable history that is invaluable for calculating reserves, identifying and correcting mistakes, auditing and relating data types together. Users have the choice of automatically capturing the interpretation history or inserting comments on the interpreted data set. Search tools help locate the right types of data using key words. This capability supports the 4D workflow and boosts the superiority of data management.[Page Break]

Poststack seismic processing

The software provides a highly integrated interpretation environment. Multi-discipline data types and cross discipline workflows are immediately accessible to enhance or confirm analysis and interpretations. SeisWorks is highly integrated with Landmark's suite of geotechnical applications for poststack seismic processing, attribute analysis tools, and geological applications. Multiple horizon tracking methods are provided. Automated methods offer rapid horizon picking in any direction across a survey. In difficult areas manual picking provides the ultimate control.

Interpretation from well data is easily incorporated into the seismic interpretation process. SeisWorks reads real-time updates from PetroWorks and StratWorks through OpenWorks. Information from SeisWorks can be sent to StratWorks and PetroWorks via a Pointing Dispatcher (PD) interactive utility. Depth-to-time utilities, integrated display of the well track, geologic tops and curves along the horizontal or recumbent well bore, synthetic overlays, and basic synthetic manipulation combine to leverage geologic data in a seismic interpretation workflow.

PowerView functionality provides a novel and innovative visual analysis environment for viewing maps or cross-sections. Simultaneous displays of virtually unlimited number of map and/or cross-section windows are supported. Cursor movements, cross hairs, zoom control, and polygon selection are shared (mimicked) between all the windows, yet each window can have independent colour ramps to highlight the specific data or attribute in each window.

PowerView map and cross-section views support multiple data layers and RGB transparency control for attribute 'blending', a powerful analysis technique for high resolution spectral decomposition imaging. On-the-fly mathematical operations provide a novel way to look at differences in data. "A perfect analysis tool for a 4-D seismic interpretation," says the company.

Power Calculator creates logical and mathematical equations for operations on horizons. Algorithms and workflows can be saved in a flowchart format then repeated from day to day or from dataset to dataset. The drag-and-drop feature streamlines data input into any flowchart. Output can be previewed before writing out the results to disk.[Page Break]

For its part, Petrel seismic interpretation software from Schlumberger seamlessly combines the workflows of 2D interpretation with the visual and performance benefits of 3D volume interpretation.

Users can leverage an interpretation environment unified with geology, reservoir modelling, and reservoir engineering domains and have the ability to rapidly interpret seismic data and compare the results with other data in a project. Effortlessly move from interpretation to structural model building to property modelling and back, eliminating the gaps and inevitable knowledge and data loss of traditional systems that require handoffs from one technical domain to the next.

The company says that users also unlock more information from 2D seismic data by applying techniques that are typically reserved for 3D interpretation, including opacity control in the 3D canvas. In addition, massive amounts of 3D data can be visualised and interpreted without loading all the data to RAM.

"Combine the traditional line-by-line approach with the latest algorithms and tools, including amplitude- and waveform-based tracking, for 3D volume interpretation. Rapidly identify stratigraphic or structural features, and then interpret horizon and fault though the volumes," says Schlumberger.

Petrel interprets across multiple 3D and 2D surveys - either in the interpretation or in 3D windows - to gain the best understanding in the shortest time. Users can also interpret the same event across multiple surveys, and grid, contour, and map whole or partial events for individual surveys.

While users are able to pick faults in the background, Petrel software grids faults and applies fault connection rules, producing an accurate fault framework for a complex structure. Grid horizon interpretation creates a true water-tight model that can be used in the model or high-quality structural maps: and shortens the time it takes to create a complex model by providing a cleaner interpretation and creating the structural framework in advance.

Finally, using the Seismic Survey Manager to effectively manage 2D and 3D seismic data within a Petrel project, improves user experience when working with large regional areas, thousands of 2D lines with tens of thousands of traces, hundreds of kilometres and coordinate systems, and multiple 3D vintages and surveys.[Page Break]

Cross-discipline creativity

The oil and gas industry today requires more cross-discipline work than ever. Production engineers are responsible for in-depth analysis of microseismic data, performing volumetric calculations and production prediction and monitoring. Drilling engineers are working with geologists and geophysicists in critical geosteering projects like never before.

SMT KINGDOM software helps engineers work more closely with geoscience teams on these cross-discipline workflows. Multi-user simultaneous project access enables better team collaboration and end-to-end, integrated functionality allows everyone to work from the same database.

Benefits include: detailed volumetric calculations and production analysis all done within your project; simple to complex economic analysis easily accomplished for any size of prospect; and microseismic analysis with seismic attribute integration give reservoir engineers an unprecedented view into their reservoir.

In terms of microseismic data analysis, KINGDOM matches seismic data interpretation to microseismic events, generates a better understanding of reservoir to well treatments, and dynamically updates with user manipulation of microseismic events. The software also includes easy tools to lasso or digitise desired subsets in any view in order to cut or crop points, while providing dynamic visualisation of microseismic events by any attribute as applied to colour, size, and visibility.

Lastly, the official release of OpendTect v4.2 is now available from the company's download centre. OpendTect is the first seismic interpretation system to support Wacom digitising tablets. Workflows for horizon tracking, fault interpretation, drawing of polygons and more have been adapted to benefit from the superior hand-eye co-ordination offered by the pen device.

SMT says that the cross-plot tool has been enhanced considerably. It now supports colour-coding of wells and attributes and generation of probability density functions (PDFs) and Bayesian inversion work flows.

Other highlights include: low frequency model building using HorizonCube data; improved Stratigraphic Model building; multimachine batch processing on Windows; gridding using GMT algorithms; improved 2D Viewer (such as added tree, horizon/fault tracking); export of cultural data to GoogleEarth: wells, survey area, 2D lines, random lines, polygons; directional lighting; interactive fault construction from faultstick sets; translation of gui text using Google-translate; and new toolbar icons

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