The Industry is gradually building up its experience in the use of time-lapse seismic data for reservoir monitoring. At the close of 1997 approximately 50 firm projects are either underway or have been completed, over a wide geographical area (as shown in the map below) and many more are under consideration as “feasibility studies.” The number of these projects which can be called successful commercial case histories is of course still fairly small — probably not more than half a dozen, and many questions about the technique remain to be answered.

In this paper we will give management and technical staff a summary of these questions and go on to answer as many of them as possible, illustrating some of the pitfalls which will be encountered. For example we will demonstrate how difficult it can be to repeat the seismic data product, with a range of examples from both the land and marine environments. But we will also show how older “legacy” data can contribute to the time-lapse science despite repeatability problems. Most important, we will summarise the feasibility studies which are essential in order to put some risk figure on potential time-lapse projects.

We will discuss project costs and timetables, and the value of a successful project. We will show why there is so much industry interest in the method, and we will give a view of the interpretation of time-lapse data results, which is an area of current research in many companies and institutions. This will lead to a statement on expectations and how to manage them.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah