The Saudi Arabian Oil Company (Saudi Aramco) first employed 3-D seismic as a field development tool in 1978. Since that time, improvemems in the technology of 3-D seismic acquisition, processing and interpretation have brought the process to new levels of quality assurance, integration and value. Geophysical service companies, computer hardware manufacturers and industry-related software developers are all challenged by the pace and demand for new advances in 3-D seismic. Worldwide utilization of 3-D seismic in both field development and exploration continues to grow. This trend is also part of the Saudi Aramco experience.
Confronted by giant oil field development and the scale of 3-D seismic projects in Saudi Arabia, new "systems" of technology and people have evolved within Saudi Aramco to manage large volumes of data, analyze the information it contains and formulate economic decisions from the results. This new technology direction is driven by corporate objectives and the cost-effective identification, evaluation and implementation of the "systems" required to meet those goals.
Since the start of modem 3-D seismic recording and processing in Abu Jifan Field in 1991, Saudi Aramco has conducted 3-D seismic surveys in Hawtah, Ghinah, Hazmiyah, Nuayyim, Ghawar, Shaybah and Marjan fields. During 1992, land seismic reflection crews recorded 1746 square kilometers of 3-D seismic data. In the marine area, 1063 square kilometers of 3-D seismic data were recorded in Marjan Field. Through 1993, these activity levels remained the same with 797 square kilometers of 3-D seismic data being recorded in, Marjan and 1540 square kilometers of 3-D seismic data being recorded for onshore field development.
In 1994, 3-D seismic crews will conduct land surveys in Shaybah, Ghawar and Abqaiq Fields resulting in approximately 2845 square kilometers. In the offshore area, an estimated 75o square kilometers of 3-D seismic data will be recorded in Zuluf Field during 1995. These levels of activity demonstrate the successful transfer of 3-D seismic technology to Saudi Aramco (Table 1).
TABLE 1:3-D SEISMIC SURVEYS(Available in full paper)
Exploration and field development in Saudi Arabia cover both structurally and stratigraphically complex environments with large areal extent. Seismic data is often characterized with strong multiple energy combined with surface and scattered waves which mask primary reflection events. In order to attack these problems and properly image the target reservoirs, Saudi Aramco's Geophysical Research & Development Division has implemented a series of proprietary algorithms for processing 3-D seismic data. These algorithms are currently developed on Saudi Aramco's Cray YMP-8E supercomputer and are routinely used by the production processing groups. This section presents two methodologies based on these algorithms which aim to improve the quality of 3-D seismic data as well as obtain reservoir characteristics from seismic derived attributes.
The first methodology aimed at extracting signal from noisy surface seismic data is based on a proper decomposition of the data via successive RADON transforms. Pre-stack signal-to-noise improvement is accomplished by applying linear and parabolic RADON transforms in succession on shot and CMP sorted data respectively.
