A subsea hydrocarbon production field includes a number of first subsea christmas trees, a first manifold, a number of first flexible flowline jumpers, each of which is connected between the first manifold and a corresponding first tree. Each first flowline jumper includes a first flow conduit and a number of first umbilical lines, and each first flowline jumper includes a first end which is removably connected to a corresponding first tree by a first multibore hub and connector arrangement and a second end which is removably connected to the first manifold by a second multibore hub and connector arrangement.

A subsea hydrocarbon production field includes a number of first subsea christmas trees, a first manifold, a number of first flexible flowline jumpers, each of which is connected between the first manifold and a corresponding first tree. Each first flowline jumper includes a first flow conduit and a number of first umbilical lines, and each first flowline jumper includes a first end which is removably connected to a corresponding first tree by a first multibore hub and connector arrangement and a second end which is removably connected to the first manifold by a second multibore hub and connector arrangement.

A subsea wellhead assembly 1 comprises: a subsea wellhead 2; a template 6 associated with the wellhead; subsea riser system equipment 4 connected to the wellhead and one or more connection members. The subsea riser system equipment 4 is also connected to the template 6 by the one or more connection members so that lateral support is provided to the subsea riser system equipment 4 from the template. A method of installing the subsea wellhead assembly 1 is also provided.

A choke and kill system, and a method of adapting a low pressure drilling rig for use in a high pressure application are described. The system has a low pressure stack and a high pressure blowout preventer stack fluidly connected to the low pressure stack. A choke is fluidly connected to a low pressure choke line of the low pressure stack and is connected to a high pressure choke line of the high pressure blowout preventer stack. The choke is adapted to reduce the pressure from the high pressure choke line to the low pressure choke line.

A choke and kill system, and a method of adapting a low pressure drilling rig for use in a high pressure application are described. The system has a low pressure stack and a high pressure blowout preventer stack fluidly connected to the low pressure stack. A choke is fluidly connected to a low pressure choke line of the low pressure stack and is connected to a high pressure choke line of the high pressure blowout preventer stack. The choke is adapted to reduce the pressure from the high pressure choke line to the low pressure choke line.

A sensor system for a dual bottle accumulator utilized with a subsea blowout preventer that monitors piston position with a position sensor in the hydraulic bottle, the gas pressure in the associated gas bottle with one or more pressure sensors, and sensors and remote actuators for associated valves.

An initiator monitoring and actuating system includes a first power supply selectively electrically connectable to a charge initiator. The first power supply provides a current lower than an activation current of the initiator. A second power supply is selectively electrically connectable to the charge initiator. The second power supply provides a current of at least the activation current. Switches are selectively operable to connect the second power supply to a test circuit operable to measure a current generated by the second power supply. The switches are selectively operable to connect the second power supply to the charge initiator. A current sensor is operable to measure current through the test circuit and operable to measure current from the first power supply when the first power supply is connected to the charge initiator.

The present disclosure belongs to the field of petroleum engineering, and specifically relates to a subsea Christmas tree re-prediction method integrating Kalman filter and Bayesian network. The subsea Christmas tree re-prediction method integrating Kalman filter and Bayesian network includes three steps: digital twin model establishment, degradation process re-prediction model establishment, and remaining useful life calculation model establishment. The subsea Christmas tree re-prediction system integrating Kalman filter and Bayesian network includes a subsea distribution unit information acquisition subsystem mounted on an subsea distribution unit, a subsea control module information acquisition subsystem mounted on a subsea control module, a subsea valve bank information acquisition subsystem mounted on a subsea valve bank, a wellhead mechanical module information acquisition subsystem mounted on a wellhead mechanical module, a subsea environmental information acquisition module mounted on a subsea control module, and a subsea Christmas tree digital twin subsystem mounted in an overwater control station.

The present disclosure belongs to the field of petroleum engineering, and specifically relates to a subsea Christmas tree re-prediction method integrating Kalman filter and Bayesian network. The subsea Christmas tree re-prediction method integrating Kalman filter and Bayesian network includes three steps: digital twin model establishment, degradation process re-prediction model establishment, and remaining useful life calculation model establishment. The subsea Christmas tree re-prediction system integrating Kalman filter and Bayesian network includes a subsea distribution unit information acquisition subsystem mounted on an subsea distribution unit, a subsea control module information acquisition subsystem mounted on a subsea control module, a subsea valve bank information acquisition subsystem mounted on a subsea valve bank, a wellhead mechanical module information acquisition subsystem mounted on a wellhead mechanical module, a subsea environmental information acquisition module mounted on a subsea control module, and a subsea Christmas tree digital twin subsystem mounted in an overwater control station.

In a subsea blowout preventer stack system having a structural system and one or more accumulators providing a pressurized hydraulic supply wherein the accumulators comprise a compressed gas supply and a hydraulic fluid chamber in one or more vertical bottles, a method of using the one or more vertical bottles of the accumulators as structural members of the structural system.