A method for locating a buried casing stub may comprise a) identifying a target region, b) providing at each of a plurality of survey points in the target region a casing stub locator that includes a vector magnetometer, c) measuring the magnetic field at each of the survey points using the vector magnetometer so as to generate a plurality of magnetic field measurements, d) using the magnetic field measurements to generate a model of the magnetic field of the target region, e) fitting the model generated in step d) to a selected model of a magnetic anomaly created by the casing stub so as to generate model fit information (MFI), and f) locating the casing stub using the MFI. At each survey point, an expected Earth magnetic field can be subtracted from the measured magnetic field. A total station can measure the position and/or the azimuth of the package.

A method for locating a buried casing stub may comprise a) identifying a target region, b) providing at each of a plurality of survey points in the target region a casing stub locator that includes a vector magnetometer, c) measuring the magnetic field at each of the survey points using the vector magnetometer so as to generate a plurality of magnetic field measurements, d) using the magnetic field measurements to generate a model of the magnetic field of the target region, e) fitting the model generated in step d) to a selected model of a magnetic anomaly created by the casing stub so as to generate model fit information (MFI), and f) locating the casing stub using the MFI. At each survey point, an expected Earth magnetic field can be subtracted from the measured magnetic field. A total station can measure the position and/or the azimuth of the package.

A technique is provided for properly orienting a subsea tree with respect to a tubing hanger landed in a subsea wellhead. An alignment ring is rotationally positioned on the subsea wellhead such that a coarse alignment feature of the alignment ring is at a desired angular orientation with respect to a fine alignment feature on the tubing hanger. The alignment ring is then secured to the subsea wellhead. Subsequently, a subsea tree may be rotationally oriented with respect to the tubing hanger as the subsea tree is landed on the subsea wellhead. As the subsea tree engages the coarse alignment feature, the coarse alignment feature guides the subsea tree into engagement with the fine alignment feature of the tubing hanger to ensure proper rotational orientation as landing of the subsea tree is completed.

A riser disconnect/reconnect system having a disconnection package (RDP) and a modified lower marine riser package (LMRP) are provided for quick disconnection of the marine drilling riser (MDR) from the LMRP to facilitate access to the LMRP or BOP stack. The RDP includes a flex joint and a hydraulically-actuated release connector (RC) with a connecting mandrel that engages a modified LMRP. In an emergency, the RDP is disconnected from the LMRP allowing access to the BOP stack for intervention. The RDP may be disconnected from the LMRP for recovery of the LMRP or BOP stack to the surface for repair or maintenance without recovering the MDR. The RC joins the flex joint to the uppermost annular blowout preventer in the LMRP. The release connector can be used in a standard or inverted position. Also provided are structural cages with complementary stab plates allowing access to various bypass ports and controls.

A wellhead system includes a wellhead assembly which is generally tubular, a landing string assembly, and an orientation sensor assembly which is mounted on the landing string assembly. The wellhead assembly is secured to a top of a borehole and has an orientation engagement part. The landing string assembly is lowered into the wellhead assembly to land in the wellhead assembly. The landing string assembly has an orientation part with an orientation feature. The orientation engagement part of the wellhead assembly corresponds to the orientation feature. As the landing string assembly is lowered into the wellhead assembly, the orientation feature engages with the orientation engagement part to rotate the landing string assembly about its longitudinal axis into a desired orientation relative to the wellhead assembly. The orientation sensor assembly measures an angular rotation of the landing string assembly about its longitudinal axis.

A landing string system and method therefor are provided. The landing string system has a measurement device with mechanical sensors that observe mechanical conditions associated with a landing string. Data-storage devices are in communication with the measurement device. The data-storage devices allow storage, from time to time, of data associated with the observed mechanical conditions. A power assembly provides power to the data-storage devices for at least an expected time of service of the system.

A method for locating a buried casing stub may comprise a) identifying a target region, b) providing at each of a plurality of survey points in the target region a casing stub locator that includes a vector magnetometer, c) measuring the magnetic field at each of the survey points using the vector magnetometer so as to generate a plurality of magnetic field measurements, d) using the magnetic field measurements to generate a model of the magnetic field of the target region, e) fitting the model generated in step d) to a selected model of a magnetic anomaly created by the casing stub so as to generate model fit information (MFI), and f) locating the casing stub using the MFI. At each survey point, an expected Earth magnetic field can be subtracted from the measured magnetic field. A total station can measure the position and/or the azimuth of the package.

An apparatus including an external surface portion shaped so as to mate with a docking device, and two half-shells having internal surfaces of semi-circular cross section. The apparatus further includes a plurality of segments arranged inside the two half-shells and including teeth for gripping onto a shaft, and an installation tool operable to cause the two half-shells to close around the shaft, thereby securing the apparatus to the shaft.

A device for facilitating the connection of fluid pipes, particularly for subsea oils and gas equipment. The device has a funnel shaped opening at the top and bottom and a cavity therebetween for holding a hub clamp. The funnel shaped openings facilitate alignment and insertion of pipes, caps, etc. to be connected by the hub clamp. The device may be installed or removed in subsea environments without raising other equipment.

A landing string includes a valve having a valve member mounted within a flow path extending through the landing string, and a valve control system for use in operating the valve to move the valve member between open and closed positions to control flow along the flow path. The valve control system is reconfigurable between a first configuration in which the valve is operated or controlled under a fail-as-is (FAI) mode of operation, and a second configuration in which the valve is operated or controlled under a fail-close (FC) mode of operation.