Page 49 - Acquisition and Processing of Marine Seismic Data

40 2. MARINE SEISMIC DATA ACQUISITION

TABLE 2.1 Different Types of Marine Seismic Surveys, Components of Recorded Data, and General Applications
of the Techniques

Method Dimension Component Area of Application
Towed streamer acquisition 2D, 3D, 4D 1C, 2C, 3C Exploration and development, used by academia and oil
and gas industry
Transition zone acquisition 2D, 3D, 4D 1C, 2C Exploration and development, commonly used by oil
and gas industry
Ocean bottom seismometer (OBS) 2D, 3D 4C Mainly for exploration, commonly used by academia
Ocean bottom nodes (OBN) 3D, 4D 4C Reservoir characterization and monitoring, used by oil
and gas industry
Ocean bottom cables (OBC) 3D, 4D 2C, 4C Reservoir characterization and monitoring, used by oil
and gas industry
1C: one hydrophone, 2C: one hydrophone and one velocimeter, 4C: one hydrophone and three accelerometers for x, y, and z components.

with a time period of several months to several during the acquisition. Fig. 2.2 shows a general
years. This operation is known as time-lapse or block diagram of a marine seismic acquisition
4D seismic. system. These specific systems and equipment
are introduced and their basic specifications
2.1 COMPONENTS OF MARINE are described in this section.
SEISMIC ACQUISITION Before starting the survey, navigation sensors,
including the gyrocompass (the electronic com-
Acquisition of marine seismic data requires pass device) and motion sensor (for heave, roll
several different systems and software packages and pitch data) as well as the single-beam echo-
to compatibly work simultaneously, which are sounder must be calibrated. DGPS (differential
in communication with each other in real-time GPS) signal verification must be performed to

FIG. 2.2 General block diagram and components of a basic towed streamer marine seismic acquisition system.