Disconnect information and monitoring system for dynamically positioned offshore drilling rigs

A disconnect information and monitoring system for a dynamically positioned offshore drilling rig at an ocean surface rig location drilling an offshore well through a riser connected to a wellhead on the sea floor, said system comprising:

• A) a data processing computer,
• B) a GPS monitor,
• C) a flex joint angle monitor,
• D) a slip joint stroke position monitor,
• E) signal equipment to feed signals from said GPS monitor, said flex joint angle monitor, and said slip joint stroke position monitor to said data processing computer,
• F) a plurality of acoustic transceiver attached at a plurality of positions on said riser and associated signal equipment to transmit location information from said transceivers to said computer,
• said computer being programmed with software to analyze signal data from said GPS monitor, said flex joint angle monitor, said slip joint stroke position monitor and said acoustic transceivers and to present the results of the analysis so as to provide guidance to controllers of said rig.

A system for determining the curvature profile of a riser suspended from a floating marine platform and minimizing said curvature profile, wherein the length of said riser is many order of magnitudes greater than the relative horizontal displacement of the riser, said system comprising:

• A. an angle sensing means for producing angle signals representing the tilt angles and azimuth angles of said flexible connecting line at positions defined by a plurality of riser mounted instrumentation and acoustic telemetry packages positioned in intervals along said flexible connecting line,
• B. a position determining means for producing x,y,z position signals of said flexible connecting line at positions defined by each of said riser mounted instrumentation and acoustic telemetry packages,
• C. a signal processing means for combining said angle signals and said position signals to determine said curvature profile and defining said curvature profile by output signals, and
• D. a position correction means for correcting said position of said platform in response to said output signals to minimize said curvature profile.

A method for determining the curvature profile of a riser suspended from a floating marine platform and minimizing said curvature profile, wherein the length of said riser is many order of magnitudes greater than the relative horizontal displacement of the riser, said method comprising the steps of:

• A. producing angle signals representing the tilt angles and azimuth angles of said flexible connecting line at positions defined by a plurality of riser mounted instrumentation and acoustic telemetry packages positioned in intervals along said flexible connecting line,
• B. producing x,y,z position signals of said flexible connecting line at positions defined by each of said riser mounted instrumentation and acoustic telemetry packages,
• C. combining said angle signals and said position signals to determine said curvature profile and defining said curvature profile by output signals, and
• D. correcting said position of said platform in response to said output signals to minimize said curvature profile.