4D time-lapse monitoring of Chirag Field

摘要

This paper outlines the 4D time-lapse monitoring of Chirag Field through 3D seismic surveys acquired in 1995 (before the 1997 startup of production) and 2002. It highlights the processing challenges of two surveys with different acquisition parameters, provides a brief outline of the rock properties, and, finally, summarizes the interpretation results that provide important surveillance data for this billion-barrel field. Overview. Chirag is a one-billion barrel reserves segment of the giant Azeri-Chirag-Gunashli (ACG) Field. ACG lies in 150-450 m of water, about 100 km offshore the Apsheron peninsula of Azerbaijan in the south Caspian Sea. The ACG structure is an elongate anticline—some 50 km in length, over 10 km in width, and 2 km in amplitude. Structural dip typically reaches a maximum of 50° on the flanks, but can reach 80° locally. There are few seismic-scale faults, though a major reverse fault system trends parallel to strike within the oil column along the north flank of Chirag and has a maximum displacement of up to approximately 60 m. The crest of the Chirag structure is approximately 2500 m subsea and the oil column is over 900 m at the principal reservoir levels.