Abstract:
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.
Abstract:
A seismic sensor module includes sensing elements arranged in a plurality of axes to detect seismic signals in a plurality of respective directions, and a processor to receive data from the sensing elements and to determine inclinations of the axes with respect to a particular orientation. The determined inclinations are used to combine the data received from the sensing elements to derive tilt-corrected seismic data for the particular orientation.
Abstract:
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.
Abstract:
Methods and apparatuses are disclosed for replacing the individual receivers used with a seismic interferometry process with an array of seismic receivers and then manipulating the array data in order to measure and modify the typical non-uniform directionality function of the background seismic energy. The non-uniform directionality function is a significant cause of noise with seismic interferometry. Furthermore, the array of receivers may be used to significantly enhance the preferred reflection energy and damp undesirable near surface energy. The directionality function may be modified by using an array of receivers for the virtual source location of seismic interferometry to measure the non-uniform directionality function, generating multiplication factors, and applying the multiplication factors to convert the measured directionality function into a desired directionality function.
Abstract:
An accelerometer or a seismometer using an in-plane suspension geometry having a suspension plate and at least one fixed capacitive plate. The suspension plate is formed from a single piece and includes an external frame, a pair of flexural elements, and an integrated proof mass between the flexures. The flexural elements allow the proof mass to move in the sensitive direction in the plane of suspension while restricting movement in all off-axis directions. Off-axis motion of the proof mass is minimized by the use of intermediate frames disbursed within and between the flexural elements. Intermediate frames can include motion stops to prevent further relative motion during overload conditions. The device can also include a dampening structure, such as a spring or gas structure that includes a trapezoidal piston and corresponding cylinder, to provide damping during non-powered states. The capacitive plate is made of insulating material. A new method of soldering the capacitive plate to the suspension plate is also disclosed.
Abstract:
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.
Abstract:
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.
Abstract:
An acoustic sensor for use in a downhole measurement tool includes a piezo-composite transducer element. In various exemplary embodiments, the acoustic sensor further includes a composite backing layer, at least one matching layer, and a barrier layer deployed at an outermost surface of the sensor. Exemplary embodiments of this invention may advantageously withstand the extreme temperatures, pressures, and mechanical shocks frequent in downhole environments and thus may exhibit improved reliability. Exemplary embodiment of this invention may further provide improved signal to noise characteristics. Methods for fabricating acoustic sensors and downhole measurement tools are also provided.
Abstract:
A high sensitivity torque and force cantilever magnetometer having a cantilever with isolated capacitance detection and nulling circuits which provides increased sensitivity and accuracy to measurements of a magnetic moment of a sample placed on the cantilever and exposed to a magnetic field. Magnetic detection is by electrical capacitance between a metallized plate and the cantilever. Alternatively, magnetic detection is by electrical resistance of a piezoactive circuit deposited on the surface of the cantilever. The cantilever can be used to measure both isotropic and anisotropic magnetism and is capable of simultaneously measuring the electrical conductivity of the sample using an integrated electrically isolated circuit. The cantilever is constructed of multiple layers of conducting and insulating materials to eliminate leakage current. The magnetometer measures the magnitude of a current through a null detection circuit having at least one nulling loop deposited on the cantilever required to maintain a constant capacitance between the cantilever and a metallized plate to determine the magnetization of the sample. The null detection circuit eliminates capacitance drift and improves the accuracy of the magnetometer.
Abstract:
A high sensitivity torque and force cantilever magnetometer having a cantilever with isolated capacitance detection and nulling circuits which provides increased sensitivity and accuracy to measurements of a magnetic moment of a sample placed on the cantilever and exposed to a magnetic field. Magnetic detection is by electrical capacitance between a metallized plate and the cantilever. Alternatively, magnetic detection is by electrical resistance of a piezoactive circuit deposited on the surface of the cantilever. The cantilever can be used to measure both isotropic and anisotropic magnetism and is capable of simultaneously measuring the electrical conductivity of the sample using an integrated electrically isolated circuit. The cantilever is constructed of multiple layers of conducting and insulating materials to eliminate leakage current. The magnetometer measures the magnitude of a current through a null detection circuit having nulling loops deposited on the cantilever required to maintain a constant capacitance between the cantilever and a metallized plate to determine the magnetization of the sample. A magnetometer having two cantilevers where one cantilever is used as a reference to eliminate background noise and temperature and magnetic field variations from measurements taken of a sample on the second cantilever is also provided. The null detection circuit eliminates capacitance drift and improves the accuracy of the magnetometer.