Composite riser with integrity monitoring apparatus and method

Abstract

An integrity monitoring system for monitoring degradation in a composite riser string. The system includes composite riser structures incorporating strain and vibration sensors to measure changes in the stiffness strain on a first orientation and on a second orientation. The system can also include monitoring modules attached to each individual riser and devices to transfer the data from the monitoring module to the surface controller. Additionally, the monitor system can provide for an alarm when predetermined warning limits are exceeded.

1 . A composite riser assembly comprising: 
 a surface platform for supporting composite risers;    at least one composite riser supported by said platform, at least one of said one composite risers having a first strain sensor affixed thereto;    a controller located at said surface platform;    said controller being in signal communication with said first strain sensors in said at least one composite riser; and    said controller having a signal device capable of transmitting signals to and receiving signals from said first strain sensors in said at least one composite riser.    
   
   
       2 . A riser assembly of  claim 1  wherein said processor includes an output means to display the measured strain data.  
   
   
       3 . A riser assembly of  claim 1  wherein said controller has a memory device for storage of strain data.  
   
   
       4 . A riser assembly of  claim 1  wherein said controller compares measured strain data to a predetermined warning value.  
   
   
       5 . A riser assembly of  claim 1  wherein said first strain sensor is in a first orientation and further comprising a second strain sensor in at least one of said composite risers, said second sensor being in a second orientation.  
   
   
       6 . A riser assembly of  claim 1  wherein said strain sensor is selected from the group consisting of fiber optic strain gauges, magnetic strain gauges, vibrational sensors, and electrical resistance strain gauges.  
   
   
       7 . A riser assembly of  claim 1  wherein said signal communication is provided by a transmission line from said platform to said strain sensors.  
   
   
       8 . A riser assembly of  claim 1  wherein said signal communication is provided by acoustic modems.  
   
   
       9 . A composite structure comprising: 
 an elongated composite structure defining an axis;    a first strain sensor associated with said composite structure at a first orientation relative to said axis to measure strain in the direction of said first orientation; and    a second strain sensor associated with said composite structure at a second orientation relative to said axis to measure strain in the direction of said second orientation.    
   
   
       10 . A composite structure of  claim 9  wherein said first and second strain sensors are fiber optic.  
   
   
       11 . A composite structure of  claim 10  wherein said first and second strain sensors are embedded in said composite structure.  
   
   
       12 . A composite structure of  claim 9  wherein said first and second strain sensors are magnetic.  
   
   
       13 . A composite structure of  claim 10  wherein said strain sensors are selected from the group consisting of fiber optic strain gauges, magnetic strain gauges, vibrational sensors, and electrical resistance strain gauges.  
   
   
       14 . A composite structure of  claim 10  wherein said vibrational sensors are mounted to establish changes in the vibration signature in the first and second orientations.  
   
   
       15 . A composite structure with monitoring device comprising: 
 an elongated composite structure defining an axis;    a first strain sensor affixed to said composite structure at a first orientation relative to said axis to measure strain in the direction of said first orientation;    a first strain monitoring module in signal communication with said first strain sensor for measuring strain;    said first strain monitoring module associated with said first strain sensors having 
 a power source,  
 a central processor unit,  
 a signal device, and  
 a communication device.  
   
   
   
       16 . A composite structure of  claim 15  wherein said module includes a storage means for storing strain data.  
   
   
       17 . A monitoring module for use with a composite riser comprising: 
 an input means for inputting strain measurements from a first strain sensor;    a processor means for receiving said strain measurement data; and    a communication means for transmitting the recorded strain data to a receiving unit.    
   
   
       18 . A monitoring module for use with a composite riser comprising: 
 an input means for inputting strain measurements from a first strain sensor in a first orientation and from a second strain sensor in a second orientation;    a processor unit for recording said strain measurements from said strain gauges; and    communication means for outputting said recorded strain measurements.    
   
   
       19 . A monitoring module of  claim 18  wherein said processor unit includes a means to compare said strain measurement data to one or more predetermined warning limit.  
   
   
       20 . A monitoring module of  claim 18  wherein said processor unit includes a means to compute the ratio of the strain measurement data in either said first or second orientation to that in the other orientation.  
   
   
       21 . A monitoring module of  claim 20  wherein said processor unit includes a means to compare said strain measurement data to one or more predetermined warning limit.  
   
   
       22 . A monitoring device for monitoring strain in a composite riser having at least one strain sensor in operative association therewith comprising: 
 means to receive strain measurements from at least one strain sensor;    means to store said strain measurement data and the time of measurement; and    means to communicate said strain measurement data to a receiver.    
   
   
       23 . A monitoring module of  claim 22  further comprising: 
 means to compare said strain measurement data with a predetermined warning value; and    means to transmit an alarm signal when said predetermined warning value is exceeded.    
   
   
       24 . A system for monitoring strain in a composite riser having at least one strain associated therewith comprising: 
 a submersible vehicle having a recorder mounted thereon;    said recorder comprising a central processing unit, a communication means, a means to receive and record strain data received from said strain sensors associated with said composite riser.    
   
   
       25 . A system of  claim 24  further comprising: 
 a means to storage strain data in said recorder.    
   
   
       26 . A system of  claim 25  further comprising: 
 a means to generate a signal for transmission to said strain sensors in order to measure strain.    
   
   
       27 . A method of monitoring strain in an underwater composite riser comprising: 
 providing a submersible vehicle with a recorder device;    sending a signal to a strain sensor attached to a composite riser from the recorder of said submersible vessel; and    recording the response to said signal in said recorder device.    
   
   
       28 . A method of monitoring strain is an underwater composite riser comprising: 
 sending a signal to a strain sensor in operative association with a composite riser;    receiving the response to the signal; and    storing the response to the signal.    
   
   
       29 . A method of  claim 28  further comprising outputting of said response.  
   
   
       30 . A method of monitoring strain in composite riser comprising: 
 providing a strain sensor in association with a composite riser;    providing a monitoring module on said composite riser;    placing said monitoring module in signal communication with said strain sensor; and    sending a strain measuring signal to said strain sensor.    
   
   
       31 . A method of  claim 30  further comprising: 
 transmitting the strain data from said monitoring module to the a surface receiver.    
   
   
       32 . A method of  claim 30  further comprising: 
 acoustically transmitting the strain data from said monitoring module to a surface receiver.    
   
   
       33 . A method of  claim 30  further comprising: 
 transmitting the strain data from said monitoring module to the a submersible vehicle.    
   
   
       34 . A monitoring module for use with a composite riser comprising: 
 a housing;    a mounting device adapted to mount said housing on a composite riser;    at least one strain gauge interface for providing a data interface for a strain gauge;    a processing device, disposed in said housing, for receiving data obtained from a strain gauge and for processing that received data in accordance with predetermined principles;    a storage device, connected to said processing device, for storing at least one of data obtained from a strain gauge and data processed by said processing device;    a communications interface, connected to said processing device, for transmitting data from said monitoring module to a receiver; and    a power interface for receiving power from a power source.    
   
   
       35 . A monitoring module of  claim 34  further comprising a memory for storing instructions for controlling an operation of said processing device.  
   
   
       36 . A monitoring module of  claim 34  further comprising a command interface for transmitting and receiving command communications for controlling said monitoring module.  
   
   
       37 . A monitoring module of  claim 34  wherein said monitoring module comprises at least two strain gauge interfaces, each strain gauge interface for providing a data interface for a corresponding strain gauge.  
   
   
       38 . A monitoring module of  claim 35  wherein said memory additionally stores strain threshold data and wherein said instructions for controlling an operation of said processing device include instructions for controlling said processing device to compare strain data received via said at least one strain gauge interface to said strain threshold.  
   
   
       39 . A monitoring module of  claim 35  wherein said memory stores instructions for controlling an operation of said processing device.  
   
   
       40 . A riser assembly of  claim 1  wherein said composite riser has an elastic axial modulus of from 5 to 15 million pounds per square inch.  
   
   
       41 . A composite structure of  claim 9  wherein said elongated composite structure has an elastic axial modulus of from 5 to 15 million pounds per square inch.  
   
   
       42 . A composite structure of  claim 14  wherein said elongated composite structure has an elastic axial modulus of from 5 to 15 million pounds per square inch.