MARINE SEISMIC

MARINE SEISMICGian Angga Ginanjar

WISFIROUTLINECHAPTER I1.1The Seismic StreamerHydrophoneElectronic modules/ digitizing bubble1.2Depth Control Unit/ Bird1.3The Seismic Source1.4The TailbuoyReferencesThe seismic streamer/cable detects the reflected energy that travels from the seismic source, through the water layer, down through the earth layer, and back up to the surface using hydrophones

1.1THE SEISMIC STREAMERThe Streamer has diameter 7cm and length depends on the depth surveySource: Ensiklopediseismik

The streamer is composed of several different pieces

HydrophonesElectronic modules/ digitizing bubbleDepth control unit/ bird

1.1THE SEISMIC STREAMERa.HydrophoneA device designed for use in detecting seismic energy in the form of pressure changes under water

Active streamer100 m sectionsGroup length options: 6.25 and 12.5 mHydrophone groups overlap between sections16 hydrophones in one 12.5 group

Source: Seismic acquisition recordingb.Electronic modules/ digitizing bubbleElectronic modules, which digitise and transmit the seismic data

Digitizing bubble:Diameter as streamerReceiver signals group, process and convert them to digital signalsThe bubbles also help to control depth-control bird of the streamer in the waterSource: Geco-prakla1.2DEPTH CONTROL UNIT/BIRDDepth control units/birds are used to control the depth of the streamer

Source: IAGC1.3THE SEISMIC SOURCEThe output of an airgun is directly proportional to the operating pressure of the airgun (2000-2500 psi)The output of an airgun increases as the cube root of the volume

Source: IAGC

1.4THE TAILBUOYTail buoy is connected to the end of each streamer to provide hazard warning of the submerged towed streamer

Source: IAGCReferencesInternational Association of Geophyisical Contractors (2011). An Overview of Marine Seismic Operations. Jurnal of OGP, No. 448.