3-D Seismic Surveys Impact Significantly on Exploration and Production
Authors: Nestvold E.O. 
Published: October 2008

ABSTRACT
The significance of 3-D seismic data in the petroleum industry during the past decade cannot be overstated. Having started as a technology too expensive to be utilized except by major oil companies, 3-D seismic technology is now routinely used also by independent operators. In the early days of 3-D seismic use the 1970s and early 1980s- surveys were commissioned largely to appraise a discovery, and then only over a small area surrounding the discovery well. Since then, the use of 3-D surveys has grown to include exploration surveys, on the one hand, and surveys over producing fields, on the other. In fact, operators are adding significant value by using 3-D surveys to rejuvenate old fields with declining production profiles. Key technology developments contributing to the success have been multi-streamer, multi-source, multi-vessel marine technology including onboard processing, 3-D depth imaging with parallel computing, and major advances in RISC workstation technology. 3-D seismic data have had an important impact in integrating technologies, because all disciplines ? ic., geophysics, geology, and reservoir engineering are beginning to use 3-D surveys as a basis for reservoir modeling during the entire life history of each field. In many cases, as fields are produced, reservoir models are updated continuosly based on all the field data, including repeat 3-D surveys.

INTRODUCTION
The significance of 3-D seismic data in the petroleum industry during the past decade cannot be overstated. What started as a technology too expensive to be utilized except by major oil companies, 3-D technology is now routinely used by independent operators in the United States and Canada. The purposes of this paper are (1) to point out some significant trends in activity as 3-D acquisition has grown and come to dominate, (2) to cite some examples of 3-D surveys, (3) to identify important technology trends, (4) to summarize industry experience with 3-D imaging ? especially rejuvenation of mature fields with declining production profiles and, (5) to give my view of the impact of 3-D seismic technology.

WORLDWIDE SEISMIC ACTIVITY
Worldwide seismic activity has been cyclical during the last two decades. Activity declined sharply coincident with the oil-price crash of 1986 and 1987. Since then the seismic world has changed dramatically, with marine activity growing more rapidly than land activity. The late 1980's and early 1990's were the boom times for marine 3-D seismic [Farestveit 1992, Morgan 1992]. This was followed by a period of decline in 3-D seismic acquisition expenditures. Three-dimensional proprietary marine acquisition may have peaked in the Gulf of Mexico and the North Sea for the time being because large proportions of prospective acreage have been surveyed. Acquisition capacity in terms of numbers of available streamers is increasing in these and other less mature offshore areas. Thus the market for first-time surveys is expected to decrease in many areas. On the other hand, surveys will be re acquired in many basins when significant improvements in resolution can be demonstrated. The historical seismic surveys repeat rate based on technology advances has been up to ten years.