Use of Collaborative Visualization Environments for Complex Depth Imaging
Authors: Hobbs Robert S. 
Published: October 2008

The advent of large non-exclusive pre-stack depth migration has made necessary the development of unique workflows and technologies. In the deepwater Gulf of Mexico, the construction of high-resolution salt models is critical for accurate depth imaging under laterally extensive and rugose salt sheets. The most critical aspect to assuring an accurate depth image is the integrity of the input velocity model. These non-exclusive depth imaging projects involved the participation of multiple stakeholders. Therefore, it was critical to provide the ability for each stakeholder to have input into construction of the velocity model. A unique interpretation environment was created that allowed all involved client interpretation teams to visualize and interpret extremely large 3D project areas. The size of these projects and the short time schedules that were required for their completion, dictated that unique workflows be developed to enable the most efficient interpretation of these structurally complex areas. This paper will discuss the unique aspects of the interpretation environment created for this project. It will also discuss the workflow designed to construct these complex velocity models and describe the process for assuring the maximum collaboration necessary for the satisfaction of multiple stakeholders. Additional projects that are being completed in these environments will be mentioned and a service company's perspective on the use of visualization will be delivered.

Introduction

Pre-stack Depth Migration (PSDM) is currently widely used for subsalt imaging improvement in the deepwater Gulf of Mexico. PSDM is a method of more accurately positioning seismic events in areas of complex subsurface structure. The advent of this seismic imaging technology has played a significant role in the growth of recent deepwater subsalt exploration activity. Exploration wells have recently been drilled in water depths of as much as 3100 meters for targets lying under thousands of meters of salt in this play. This salt canopy play lies predominately in water depths greater than 1000 feet. The Sigsbee Escarpment, a bathymeteric feature created by the southern edge of large allochthonous salt canopies, marks the southern extent of the play (Fig. 1). These salt bodies are believed to have been implaced in their current position through the vertical and lateral movement of salt up the stratigraphic section in response to differential loading of overlying, denser clastic material1. The availability of highquality non-exclusive 3D seismic data over large areas of the deepwater Gulf of Mexico has made access to PSDM technology and the subsalt play attainable to a wider variety of companies, some of which did not have access to the play previously.

The trend within exploration companies to outsource noncore activities has encouraged some seismic service companies to invest in the computing and manpower resources necessary to provide PSDM services. Service companies are taking this technology even further by providing nonexclusive, or multiclient, PSDM in areas where they have ownership in the data. The study area for this paper includes one such large project of 5000 km2 in size (Fig. 1).