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.

Abstract: A multiple sensor fiber optic sensing system includes an optical fiber having at least first fiber optic sensors and second fiber optic sensors deployed along its length. In response to an interrogating pulse, the first fiber optic sensors generate responses in a first optical spectrum window, and the second fiber optic sensors generate responses in a second, different optical spectrum window. The responses in the first optical spectrum window are measured in a first optical spectrum channel, and the responses in the second optical spectrum window are measure in a second, different optical spectrum channel and provide simultaneous indications of one or more parameters, such as temperature and pressure, in the environment in which the sensors are deployed.

Abstract: Aspects of the subject matter described herein relate to cryptographically controlling access to documents. In aspects, documents are encrypted to protect them from unauthorized access. A security principal seeking to access a document first obtains the document. The document includes an identifier that identifies security data associated with the document. The security data includes an encrypted portion that includes authorizations for security principals that have access to the document. A security principal having the appropriate key can decrypt its authorization in the security data to obtain one or more other keys that may be used to access the document. These other keys correspond to access rights that the security principal has with respect to the document.

Abstract: Transactional record management methods and systems enabling multiple independent servers (such as database servers) using shared storage to initiate transactions in parallel without inter server communication and without locking the records used by the transaction. The in-flight transactions can be included in a shared transaction log without a final determination of whether the transaction committed. The log updates can be broadcast to each of the servers, which each parse the log, using the same rules of analysis, and therefore each compute server can independently and asynchronously come to the same conclusion as to which transactions aborted and which transactions committed.

Abstract: A distributed optical acoustic sensor is provided along a structure in a body of water. The distributed optical acoustic sensor is used to detect acoustic waves generated by at least one acoustic source for positioning of at least one object in relation to the structure.

Abstract: Computers are provided with a totally ordered, durable shared log. Shared storage is used and can be directly accessed by the computers over a network. Append-log operations are made atomic in the face of failures by committing provisional append ordering information onto a log. The log may comprise multiple flash packages or non-volatile memory devices, referred to as segments, although any shared storage device(s) may be used. Each log record is a multi-page stripe, where each page of a stripe is written to a different segment. Fault-tolerant protocol variants append stripes to the log, such that stripes are totally ordered in the log and each stripe is written atomically.

Abstract: A gas detector (10) that is arranged to sense the concentration levels of target gases oxygen, methane, carbon monoxide, and hydrogen sulphide, within a gas sample from an environment surrounding the detector. The gas detector (10) comprises laser sources (12a-12d) that are arranged to transmit radiation through the gas sample at four target wavelengths that correspond approximately to the optimum absorption wavelengths of each of the target gases and an optical detector (16) that is arranged to sense the intensity of the radiation transmitted through the gas sample at each of the target wavelengths. A control system (22) generates representative concentration level information for the target gases based on the level of absorption of the radiation transmitted.

Abstract: A system for use in a well includes an optical cable for positioning in the well. An optical sensor is optically coupled to the optical cable, where the optical sensor has a capillary tube and an optical fiber in the capillary tube. The capillary tube also includes a first sealed region containing a metallic material that is in liquid form at a downhole temperature in the well. A joint mechanism may attach the optical sensor to the optical cable.

Abstract: Single fiber optical telemetry systems and methods are disclosed. The methods and systems facilitate input and output via a single fiber optic interface. The optical telemetry systems and methods also facilitate faster data transmission rates between surface and downhole equipment in oilfield applications.

Abstract: A method and apparatus for deploying seismic detectors and monitoring seismic activity associated with a production well from a down hole location within a well.

Abstract: Transactional record management methods and systems enabling multiple independent servers (such as database servers) using shared storage to initiate transactions in parallel without inter server communication and without locking the records used by the transaction. The in-flight transactions can be included in a shared transaction log without a final determination of whether the transaction committed. The log updates can be broadcast to each of the servers, which each parse the log, using the same rules of analysis, and therefore each compute server can independently and asynchronously come to the same conclusion as to which transactions aborted and which transactions committed.

Abstract: A gas detector (10) that is arranged to sense the concentration levels of target gases oxygen, methane, carbon monox-ide, and hydrogen sulphide, within a gas sample from an environment surrounding the detector. The gas detector (10) comprises laser sources (12a-12d) that are arranged to transmit radiation through the gas sample at four target wavelengths that correspond approximately to the optimum absorption wavelengths of each of the target gases and an optical detector (16) that is arranged to sense the intensity of the radiation transmitted through the gas sample at each of the target wavelengths. A control system (22) generates representative concentration level information for the target gases based on the level of absorption of the radiation transmitted.

Abstract: A system and method for optically determining the rate and/or direction of fluid flow in a conduit within wellholes, using the diffraction effect of Faraday crystals through which continuous light is transmitted within optical fibers.

Abstract: A sonde and an apparatus for the deployment thereof against a well casing is described, the sonde comprising a resilient C-shaped member and at least one sensor.

Abstract: Subterranean oilfield sensor systems and methods are provided. The subterranean oilfield sensor systems and methods facilitate downhole monitoring and high data transmission rates with power provided to at least one downhole device by a light source at the surface. In one embodiment, a system includes uphole light source, a downhole sensor, a photonic power converter at the downhole sensor, an optical fiber extending between the uphole light source and the photonic power converter, and downhole sensor electronics powered by the photonic power converter. The photonic power converter is contained in a high temperature resistant package. For example, the high temperature resistant package and photonic power converter may operate at temperatures of greater than approximately 100° C.

Abstract: Methods and apparatus for creating a velocity profile of a formation surrounding a borehole by checkshot measurements while moving the tool along the borehole. A conveyance and a sensor section are configured to move the sensor section in the borehole. At least one receiver is configured to detect signals generated at or near the surface while the sensor section is moving in the borehole.

Abstract: A seismic sensor comprising a coil assembly suspended in a magnet field produced by a magnet assembly, and a locking mechanism for preventing the coil assembly from moving freely until a seismic event is initiated at the surface or within an earth formation to collect seismic data.

Abstract: A seismic sensor comprising a coil assembly suspended in a magnet field produced by a magnet assembly, and a locking mechanism for preventing the coil assembly from moving freely until a seismic event is initiated at the surface or within an earth formation to collect seismic data.

Abstract: Single fiber optical telemetry systems and methods are disclosed. The methods and systems facilitate input and output via a single fiber optic interface. The optical telemetry systems and methods also facilitate faster data transmission rates between surface and downhole equipment in oilfield applications.

Abstract: A system and method for optically determining the rate and/or direction of fluid flow in a conduit within wellholes, using the diffraction effect of Faraday crystals through which continuous light is transmitted within optical fibers.