The Nan Yi Shan feature is a northwest trending anticline formed as a result of compressional tectonics during the early Quaternary orogeny. The structure is located in the south west corner of the Qaidam Basin approximately 2500 kilometres west of Beijing, People's Republic of China. It is associated with the crest of a large northwest plunging anticline 35 kilometres long and 7 kilometres wide. A total of ten deep wells and numerous shallow slim holes have been drilled on the Nan Yi Shan structure with mixed success.
From 1987 to 1988 a 3-D seismic survey was recorded over the crest of the Nan Yi Shan structure to define the structural and stratigraphic controls for local hydrocarbon accumulation and to determine the lateral extent of an overpressure zone that had been responsible for two major well blow outs. This thesis emphasises the results of a comprehensive structural and stratigraphic interpretation of this 3-D seismic data volume. A unique region of fracturing and associated velocity sag is discussed. In a deeper geological interval, seismic amplitudes were used to delineate the spatial limits of overpressuring. An improved understanding of the Nan Yi Shan structure and stratigraphy has resulted from the greater lateral detail provided by the 3-D method. A more accurate velocity model for depth conversion has also been possible. Based on this interpretation, it is concluded that the Nan Yi Shan anticline is a complexly folded and faulted oil and gas productive structure with potential for extended hydrocarbon production.
Areas of further work and optimum well drilling locations for the continued exploitation of hydrocarbons are recommended as a result of this project.