Air-gun source systems are key pieces of equipment used in the offshore seismic exploration of transition zones, which include swamps, water networks, rivers, lakes, beaches, and the shallow and deep seas, among others. In order to meet the requirements for seismic exploration in typical marine and aquatic areas, we need an air-gun source appropriate for the study environment. This article introduces Hai Bao 9, an integrated seismic-source vessel that is suitable for the exploration of enclosed bodies of water, such as inland lakes. This vessel can be assembled, launched, and disassembled at work sites without wharfs and can be transported on roads after disassembly. It is capable of multifunction operation, which includes a large-volume array, towing streamer, etc. This article introduces this air-gun source vessel and discusses the application background, design, and equipment specifications..
Air-gun systems are the main sources used in geophysical exploration in water, and they consist of three subsystems: a compressor, an air-gun controller, and air guns, all of which are integrated at source vessel. As air-gun systems are key pieces of equipment used in the offshore seismic exploration, the ability of the air-gun source vessel to fit the environment affects the feasibility and efficiency of exploration.
Since the 1960s, air guns have been applied to seismic exploration of various offshore areas. After years of development, researchers have created different types of airgun source equipment that can adapt to typical waters, including swamps, water networks, rivers, lakes, beaches, transition zones, the shallow and deep seas, etc., and all of these source systems meet the requirements for seismic exploration.(H.J.Li, 2007).
Generally, an OBC air-gun source vessel—Hai Bao 7 is used as an example—has the following features, as shown in Fig.1.
(1) Length: 47 m and breadth: 9 m, can be completely lifted and transported entirely in water;
(2) Draft 2.5 m, coastal area;
(3) Two air compressors discharge at a capacity of 31 m3 min-1, can be extended to four sub-arrays, maximum volume is 6000 in3;
(4) Side-hanging, side-towing, and rear-towing modes.