Back to results
US 8,559,267 B2Granted
Methods and apparatus of borehole seismic surveys
AssigneeSchlumberger Technology Corporation
InventorsJohn Richard Tulett, James Edward Martin, Emmanuel Coste, Colin Wilson
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for borehole seismic survey are disclosed comprising a first seismic source under water at a first location and a second seismic source at a second, deeper location. Seismic signals from the seismic sources are recorded with synchronized sensors located in a borehole and source signature data are obtained by combining the recorded seismic signals such that low and high frequency content of the combined source signature data is extended relative to the source signature of the first seismic source and the second seismic source.
Claims30
A method of borehole seismic survey, comprising:
- deploying a first seismic source and a second seismic source at or near a sea surface at predetermined fixed depths relative to one or more sensors located in a borehole;
- synchronizing seismic source firing with the borehole sensors recording so that seismic waves generated by the seismic sources are received by the borehole sensors;
- firing the first seismic source under water at a first depth at a first time;
- recording first seismic signals from the first seismic source with the borehole sensors, the first seismic signals having a first frequency content;
- firing the second seismic source at a second, deeper location at a second time;
- recording second seismic signals from the second seismic source with the borehole sensors, the second seismic signals having a second frequency content;
- monitoring a propagation velocity of acoustic energy in water in real time;
- controlling a firing sequence of the seismic sources to delay at least one of the first time and the second time based on the monitored propagation velocity;
- generating source signature data by combining the recorded first seismic signals and second seismic signals,
- wherein a low and high frequency content of the combined source signature data is extended relative to the first frequency content of the first seismic source and the second frequency content of the second seismic source.
7 more elements
A borehole seismic survey system comprising:
- at least a first seismic sensor configured or designed for deployment in a borehole;
- a first seismic source configured or designed for deployment under water at a predetermined fixed first location relative to the borehole sensor;
- a second seismic source configured or designed for deployment under water at a predetermined fixed second, deeper location spaced vertically from the first seismic source relative to the borehole sensor;
- a controller operatively connected to the first and second seismic sources and the first seismic sensor and configured or designed to synchronize the firing of the first seismic source at a first time and the second seismic source at a second time with borehole sensor recording,
- wherein the system is programmed to
- monitor a propagation velocity of the acoustic energy in water in real time,
- control a firing sequence of the seismic sources to delay at least one of the first time and the second time based on the monitored propagation velocity,
- record first seismic signals having a first frequency content and second seismic signals having a second frequency content received by the borehole seismic sensor from the first seismic source and the second seismic source, respectively, and to
- generate source signature data by combining the recorded first seismic signals and second seismic signals such that a low and high frequency content of the combined source signature data is extended relative to the first frequency content of the first seismic source and the second frequency content of the second seismic source.
6 more elements
A borehole seismic survey system comprising:
- a plurality of receivers deployed in a subsea borehole;
- a seismic source array aligned vertically in-sea at or near the sea surface such that each source of the source array is located at a corresponding predetermined fixed depth relative to the borehole receivers;
- an in-sea source controller configured to
- synchronize the firing of the seismic source array with borehole receiver recording and to
- sequentially fire the individual sources of the seismic source array such that at least first seismic signals having a first frequency content and second seismic signals having a second frequency content are received by the borehole receivers from a first seismic source and a second seismic source of the seismic source array, the first and second seismic sources being fired at first and second times, respectively,
- monitor a propagation velocity of acoustic energy in water in real time, and
- control a firing sequence of the seismic sources to delay at least one of the first time and the second time based on the monitored propagation velocity,
- wherein the borehole seismic survey system is configured to
- combine the first frequency content and second frequency content such that a low and high frequency content of a combined source signature data is extended relative to the source signature of the first seismic source and the source signature of the second seismic source.
6 more elements
Dependencies are inferred from the claim text.