Abstract:
A housing for a seismic sensing element (3) for use on the earth's surface comprises connecting means (5) for connecting the housing (3) to a support cable (2) so as to allow relative movement between the sensor housing (3) and the cable (2). This de-couples the sensor housing from the support cable, and improves the fidelity of the sensor.The connecting means (5) preferably comprises resilient connecting elements, to prevent the transmission of vibrations between the support cable and the sensor housing.The sensor housing (3) preferably has a flat base (1), so that there is good coupling between the sensor housing and the earth. Alternatively, the sensor housing can be fitted with a base member ((24a, 24b, 24c) that has at least one flat face (26, 26a, 26b, 26c).
Abstract:
A technique includes towing a particle motion sensor in connection with a seismic survey and controlling the survey to cause a notch in a frequency response of the particle motion sensor to substantially coincide with a frequency band at which aliased vibration noise appears in a seismic signal acquisition space of the particle motion sensor.
Abstract:
To calibrate an accelerometer, a seismic cable that carries the accelerometer is rotated. Data measured by the accelerometer as the seismic cable is rotated is received, and at least one calibration parameter according to the received data is computed. The at least one calibration parameter is for use in calibrating the accelerometer.
Abstract:
A method of matching the impulse response of a hydrophone and the impulse of a geophone accelerometer comprises performing a calculus operation upon the response of one of the hydrophone and the accelerometer. A filter is then derived from the output of the calculus operation and the response of the other of the hydrophone and the accelerometer. The filter may then be used to match seismic data acquired by the one of the hydrophone and the accelerometer to seismic data acquired by the other of the hydrophone and the accelerometer. The calculus operation may comprise differentiating the hydrophone response, or integrating the accelerometer impulse response.
Abstract:
A technique includes obtaining different sets of data, which are provided by seismic sensors that share a tow line in common. Each data set is associated with a different spatial sampling interval. The technique includes processing the different sets of data to generate a signal that is indicative of a seismic event that is detected by the set of towed seismic sensors. The processing includes using the different spatial sampling intervals to at least partially eliminate noise from the signal.
Abstract:
A method of matching the impulse response of a hydrophone and the impulse of a geophone accelerometer comprises perfroming a calculus operation upon the response of one of the hydrophone and the accelerometer. A filter is then derived from the output of the calculus operation and the response of the other of the hydrophone and the accelerometer. The filter may then be used to match seismic data acquired by the one of the hydrophone and the accelerometer to seismic data acquired by the other of the hydrophone and the accelerometer. The calculus operation may comprise differentiating the hydrophone response, or integrating the accelerometer impulse response.
Abstract:
A method of performing a seismic survey of a hydrocarbon reservoir in the earth formations beneath a body of water includes deploying a seismic cable from a drum carried by a remotely operated vehicle on the seabed. The cable is deployed into a lined trench, which is formed either concurrently with cable deployment or during a previous survey, to ensure good repeatability of successive surveys of the reservoir, in order to enable changes in characteristics of the reservoir, eg due to depletion, to be monitored.
Abstract:
A method of performing a seismic survey of a hydrocarbon reservoir in the earth formations beneath a body of water includes deploying a seismic cable from a drum carried by a remotely operated vehicle on the seabed. The cable is deployed into a lined trench, which is formed either concurrently with cable deployment or during a previous survey, to ensure good repeatability of successive surveys of the reservoir, in order to enable changes in characteristics of the reservoir, eg due to depletion, to be monitored.
Abstract:
A method of performing a seismic survey of a hydrocarbon reservoir in the earth formations beneath a body of water includes deploying a seismic cable from a drum carried by a remotely operated vehicle on the seabed. The cable is deployed into a lined trench, which is formed either concurrently with cable deployment or during a previous survey, to ensure good repeatability of successive surveys of the reservoir, in order to enable changes in characteristics of the reservoir, eg due to depletion, to be monitored.
Abstract:
The present invention provides for cable motion detection. In one aspect of the instant invention, a method is provided for cable motion detection using orientation sensor. The method includes determining at least one initial inclination of at least one orientation sensor coupled to a seismic cable, determining at least one current inclination of the at least one orientation sensor, and determining whether the at least one seismic cable has moved from the at least one initial inclination and the at least one current inclination.