Patent classifications
G01V1/3808
Ocean bottom seismometer package
A marine seismic exploration method and system comprised of continuous recording, self-contained ocean bottom pods characterized by low profile casings. An external bumper is provided to promote ocean bottom coupling and prevent fishing net entrapment. Pods are tethered together with flexible, non-rigid, non-conducting cable used to control pod deployment. Pods are deployed and retrieved from a boat deck configured to have a storage system and a handling system to attach pods to cable on-the-fly. The storage system is a juke box configuration of slots wherein individual pods are randomly stored in the slots to permit data extraction, charging, testing and synchronizing without opening the pods. A pod may include an inertial navigation system to determine ocean floor location and a rubidium clock for timing. The system includes mathematical gimballing. The cable may include shear couplings designed to automatically shear apart if a certain level of cable tension is reached.
Variable buoyancy control and recovery system for seismic data acquisition
A seismic apparatus includes one or more seismic cable systems configured to acquire seismic data, each seismic cable system having one or more of a cable jacket, a reservoir for a ballast fluid or other ballast medium, and an actuator or other transfer mechanism configured to transfer the ballast fluid between the reservoir and the seismic cable system during acquisition of the seismic data, e.g., where the ballast fluid is transferred to the seismic cable system within the cable jacket. A controller can be configured to adjust a buoyancy of the seismic cable system responsive to the transfer of the ballast fluid, e.g., where the internal volume expands or contract based on the fluid transfer.
METHOD OF WIDE AZIMUTH PROFILING (WAP)
A seismic survey method comprising a vessel, a seismic acquisition system for collecting geophysical seismic data, a marine navigation system for generating positioning data from the location of the vessel and the location of the seismic acquisition system, a seismic data storage engaged with the seismic acquisition system for collecting and storing the seismic data and a seismic data processor engaged with said seismic data storage for seismic processing of the seismic data. The seismic data is acquired along a non-linear acquisition path or sail line. The data consists of CMP lines that follow the non-linear acquisition path. A binning grid covering the CMP lines of the acquired data such that the in-lines follow parallel to the acquisition path and the cross-lines are perpendicular to the in-lines is created. The binning grid comprises a straight portion and a curved portion. Bins for each portion of the binning grid is calculated.
Seismic data acquisition with varying relative distance between multiple seismic vessels
The present invention generally relates to marine seismic prospecting, and in particular to seismic prospecting using multiple vessels. During acquisition of seismic data, a distance between a first seismic vessel and a second seismic vessel may be adjusted according to a predefined function such that data is collected at a variety of offsets.
Simultaneous sourcing during both seismic acquisition and seismic inversion
Method for acquiring, at reduced acquisition cost, seismic data using simultaneous, field-encoded sources in the field (702), and then constructing pseudo source-records (703) that better meet the requirements for using additional simultaneous computer-encoded sourcing for computer simulations or forward modeling (706) as part of (707) iterative FWI (Full Wavefield Inversion) or RTM (Reverse Time Migration), with additional reduction in computational costs. By better meeting the requirements of simultaneous sourcing for FWI or RTM (701), artifacts and crosstalk are reduced in the output. The method can be used for marine streamer acquisition and other non-fixed spread geometries to acquire both positive and negative offsets and to mitigate the “missing data” problem for simultaneous-source FWI. It can also be used for land data to overcome issues with moving spreads and long continuous records.
Method to Estimate and Remove Direct Arrivals From Arrayed Marine Sources
A method for obtaining zero-offset and near zero offset seismic data from a marine survey, with separation of direct arrival information and reflectivity information, the method including: modeling a direct arrival estimate at a passive near-field hydrophone array by using a notional source separation on active near-field hydrophone data; generating reflection data for the passive near-field hydrophone array by subtraction of the modeled direct wave from data recorded by the passive near-field hydrophone array; generating near zero-offset reflectivity traces by stacking the reflection data for the passive near-field hydrophone array on a string-by-string basis or on a combination of strings basis; generating reflectivity information at the active near-field hydrophone array by subtracting the direct arrival estimate modeled using the notional source separation from the active near-field hydrophone data; and generating an estimate of zero-offset reflectivity traces by calculating a cross-correlation between the between the reflectivity information at the active near-field hydrophone array and the near zero-offset traces and performing an optimized stacking with summation weights based on coefficients of the cross-correlation.
STEERING FOR COVERAGE IN SEISMIC SURVEYS
A method for steering a marine seismic acquisition system by determining a steering point associated with towed seismic equipment is described. Coverage boundaries for a current line in a seismic survey and for an already acquired adjacent line in the seismic survey are computed. Cross-line distances between the coverage boundary for the current line and the coverage boundary for the adjacent line are computed based on a set of specifications for the seismic survey. A steering point associated with towed seismic equipment is determined based on the computed cross-line distances. A least one steering command for a steering element in the marine seismic acquisition system is generated based on the determined steering point.
Method for swell effect and mis-tie correction in high-resolution seismic data using multi-beam echo sounder data
Provided is a method for swell effect and mis-tie correction in high-resolution marine seismic data using multi-beam echo sounder data, and more particularly, a method for swell effect and mis-tie correction in high-resolution marine seismic data using multi-beam echo sounder data capable of acquiring the high-resolution marine seismic data having the swell effect and the mis-tie effectively corrected by using the multi-beam echo sounder data including water depth data of a sea-bottom having high precision.
Use of vector rotational measurements and vector pressure gradient measurements to enhance spatial sampling of dual-sensor water bottom seismic data
Disclosed herein are various embodiments of a method and apparatus to enhance spatial sampling in all nominally horizontal directions for Dual-Sensor seismic data at the bottom of a body of water such as the ocean. The sensor apparatus on the water bottom is comprised of sensing elements for linear particle motion, for rotational motion, for pressure measurement, for pressure gradients, and for static orientation. Stress and wavefield conditions known at the water bottom allow numerical calculations that yield enhanced spatial sampling of pressure and nominally vertical linear particle motion, up to double the conventional (based on physical sensor locations) Nyquist spatial frequency in two nominally horizontal independent directions. The method and apparatus have a wide range of application in Ocean Bottom Seismic 3D, 4D, and Permanent Reservoir Monitoring surveys, and other marine seismic surveys, in oil and gas exploration and production.
Device and method for continuous data acquisition
Method for generating an excitation signal for a first vibratory seismic source so that the first vibratory seismic source is driven with no listening time. The method includes a step of determining a first target spectrum for the first vibratory seismic source; a step of setting a first group of constraints for the first vibratory seismic source; and a step of generating a first excitation signal for the first vibratory seismic source based on the first group of constraints and the first target spectrum. The first seismic traces recorded with plural receivers can be identified when the first vibratory seismic source is driven with no listening time, based on the first excitation signal.