There are predictable relationships between the shape of a growth normal fault and the shape of thwe associated rollover. In other words, if you know fault shape, then you can successfully predict fold shape. How these processes work are described in several of our past and pending publications, although some of our meiihods are proprietary.

One observation we wish to point out is that duplex faults commonly have low dips and therefore may image on record sections (see Figures 9-60 and 9-62, in Applied Subsurface Geological Mapping). These deeper rollovers have steeply dipping beds which do not image on record sections.

We have the "breakthrough technology" to employ the above and other new and tested methods of structural analysis, to locate new structural plays. To explore for new types of plays a company must innovate. A structural expert must be on staff, or available as a consultant, who understands complex structural analysis.

Ongoing economic success often depends on a company's ability to learn, understand, and apply new, productive, and exciting play concepts.

CONTOUR COMPATIBILITY

Structure maps on multiple horizons are often created without regard to the three dimensional validity of the interpretation as a whole. This can result in closely spaced structure maps that imply radical changes in strike, dip or thickness in very short intervals (Figure 2). The mapped horizons are only 90-95 feet apart, but the 7100 foot contours on the two maps look like they may cross just south of the map. This would make the deeper horizon shallower than the shallow horizon. In areas of steep dip, structure maps that are hundreds of feet apart can be miscontoured so that separate horizons cross each other.

When reviewing maps, one excellent QLT is to overlay the maps and verify that any changes in structure are reasonable and compatible in three dimensions. In Figure 3, the closely spaced horizons have similar strikes and dips. In steeply dipping areas, a hand sketched cross section on the mapped horizons can quickly show contouring problems. (Figure 4)

INCREASED WORKSTATION PRODUCTIVITY

Subsurface Consultants & Associates, Inc. would like to introduce our newest associate "Computer Aided Technological Services", specialists in workstation technology. C.A.T.S. has a different approach to 3-D workstation interpretation, managing a project from start to finish wholly within the seismic interpretation environment. Whereas others require two or three different software packages, typically, to interpret seismic data, integrate subsurface information, and construct a depth controlled structure map.

C.A.T.S. uses a proprietary database interface to add subsurface integration capabilities to the standard Landmark seismic interpretation software. In addition, advanced interpretation techniques, and innovative mapping techniques, as presented in the textbook "Applied Subsurface Geological Mapping", increase productivity and allow the production of show quality maps in the seismic environment. This approach allows us to perform the geologic and geophysical tasks in a common software environment. The result is unprecedented integration of geologic and geophysical data, increased accuracy, and lower overall costs. The accompanying display (Figure 5) is a portion of a map produced totally within the Landmark seismic interpretation environment. 'Through our new associate, we can now provide expanded seismic workstation services. The combination of advanced structural methods and innovative 3-D workstation techniques is a hard combination to beat.

ENGINEERING ROLE IN A FIELD STUDY

A field study is a synergistic effort involving engineering, geologic and geophysical personnel in an interactive and joint effort to locate, quantify and develop a plan to deplete the remaining oil and gas reserves on a property. The engineer incorporates production performance into the evaluation of the field. In the process the engineer verifies and modifies the geologic interpretation of the field, the rock and fluid properties, and recovery factors used to determine the reserves in the field.

Finally, the engineer develops a performance oriented plan to produce, workover, re-complete, test and develop all the remaining proved and probable reserves. The optimum plan focuses on maximizing profit and not just recovering reserves.