Riser and wellhead monitoring for improved offshore ... Jensen.pdf · Riser and wellhead monitoring...

Riser and wellhead monitoring for improved

offshore drilling operations Gullik A. Jensen, PhD

Product manager Riser Management System

Kongsberg Oil & Gas Technologies

E-mail: [email protected]

CeSOS Highlights and AMOS Visions Conference,

Trondheim, May 27th 2013

Agenda

• Introduction

– Offshore drilling with riser

– On the riser and the riser joints

– On damage and consequences

• Operational monitoring

– Instrumentation of the riser

– Monitoring of key parameters

• Decision support and guidance control

– Controlled parameters and objective

– Guidance control

• Wellhead fatigue instrumentation

– A current project by Kongsberg

• Summary

21.05.2013 WORLD CLASS - through people, technology and dedication

The KONGSBERG Riser Management Systems (RMS)

Integrity of drilling riser based on monitoring flex-joint and ball joint angles Advisory system for maintaining control of critical riser and wellhead parameters during varying environmental conditions

• Delivered with Motion Reference Unit

instruments (MRU 2) from Kongsberg Seatex

• Developed in cooperation with

Kongsberg Maritime (integrated with K-POS dynamic positioning system)

• More than 75 systems sold

Drilling Risers Riser Management Solutions

Workover Risers Riser Management Solutions

BOP WH Fatigue Condition Monitoring

Instrumentation

Integrity of workover risers based on monitoring strains in tension joint and stress joint Advisory system for maintaining control of critical riser and wellhead parameters during varying environmental conditions

• Instrumentation based on strain

gauges delivered by Force Technology

• 11 systems sold

Integrity of Wellheads

Monitoring BOP and riser motions and strains to asses wellhead fatigue and better understanding of structural behaviour

• Redundant system to secure stable,

reliable data access

• Online data distribution to the rig and to operation centres onshore

• Delivered by KOGT with Kongsberg

Maritime and MultiControl as sub-contractors

• Two systems delivered.

Offshore drilling with riser ...a quick introduction

Offshore drilling is performed from floating

drill ships or drill rigs

Courtesy of Seadrill Courtesy of Saipem

• Equipped for drilling subsea wells.

• Uses dynamic positioning system (DP) to maintain position (Kongsberg Maritime)


A riser is a conduit that provides a

temporary extension of a subsea oil well to a

surface drilling facility.

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The drilling riser is made up of many joints,

some with special purposes.

Wellhead

Lower flex joint

Upper flex joint

Standard joint

Telescopic joint

Stack

(BOP)


The riser may be subject to great loads in

bad weather conditions


This video is from YouTube

The riser flex-joints are one of the mot

important parameters for drilling operations


This video is from YouTube

Damage to the riser and wellhead can be

detected and avoided with riser monitoring

Key seating

Excessive flex joint angles

Rupture

Excessive loads or fatigue

Buckling

Insufficient top tension


The environmental damage from an

uncontrolled blowout is extremely high


There are three objectives to keep in mind

during riser operations.

Safe operation…

…deals with conduction the operation within operation

limits to ensure that undesirable events does not happen.

This is done by monitoring critical parameters.

Operation optimization…

… deals with changing the operational conditions to

reduce the risk of undesirable events happens. This is

done by advices and decision support.

Integrity management…

… deals with tracking the time in use of the riser

equipment and the estimation of the wear and tear,

including fatigue. This is used in inspection planning and

remaining joint lifetime estimation.


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Operational monitoring … ensure safe operation and avoid damage.

Real-time sensor data is collected from

sensors and external systems

External systems

DP System

Drilling Control System

Tensioner System

BOP Control System

Riser instrumentation

Inclinometers

Strain gauges

The integrity of the whole riser is monitored

by monitoring critical riser parameters

Flex joint angles

Strain and tension

in selected cross-

sections

Telescopic joint

stroke

Top tension

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Decision support and guidance control … optimize operation, reduce the risk of damage.

Critical parameters for operation can not

directly be controlled

21.05.2013 WORLD CLASS - through people, technology and dedication.

Upper flex joint angle

Tension

Lower flex joint angle

Telescopic joint stroke

Vessel position

(DP system)

Top tension

(Tensioner system)

Controlled

parameters

Critical

parameters

The control objective is to minimize the

flex-joint angles by repositioning the vessel

21.05.2013 WORLD CLASS - through people, technology and dedication.

Optimum vessel

position

Upper flex-joint

angle safe zone

Lower flex-joint

angle safe zone

Positioning control system hierarchy

Actuator control

Drilling vessel and riser Environment Sensors

DP Control

Control Allocation

Human Operator

RMS

Low Level Control

Intermediate Level Control

High Level Control

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Wellhead fatigue … instrumenting the BOP to determine wellhead fatigue.

The estimated wellhead remaining fatigue

life is short for wells in mature fields

Challenge

• The reaming fatigue life of many wellheads are very short.

• The estimation of fatigue is conservative since the true loads on the wellhead is not known.

Objective

• Calculate the wellhead fatigue in real time based on the rig actual motion and riser / BOP behaviour

• The purpose is to establish a standard for instrumentation for floating mobile drilling rigs

• Reduce uncertainty in global analysis by doing actual measurements of the BOP motions

• To achieve a better understanding of the actual risk level.

Solution

• Instrument the BOP to get as much data about motions and loads as possible.


Two drilling rigs in opposite ends of the fleet

regarding equipment and size were chosen

Courtesy of Odfjell drilling Courtesy of Transocean

DeepSea Bergen (Odfjell Drilling)

• Year entered service: 1983

• Max water depth: 450 m

• Displacement: 27,209 m/t

• Positioining system: Mooring

• BOP: NL Shaffer


Transocean Spitsbergen (Transocean)

• Year entered service: 2009

• Max water depth: 3000 m

• Displacement: 64,500 m/t

• Positioning system: Kongsberg DP class 3

• BOP: Cameron

Subsea system topology

• Strain measurements

– Bottom of BOP

– LMRP above the flex-joint

• Motion sensors (MRU5+)

– Bottom of BOP

– LMRP below the flex-joint

– LMRP above the flex-joint

– Below the upper flex-joint

– Above the upper flex-joint

• Full redundancy

– All sensors

– All communication


Instrumenting the bottom of the BOP

The spool piece directly above the wellhead connector was chosen for instrumentation.

Motion sensor Kongsberg MRU5+

Battery pack Strain sensor module

Communication module

All pictures is the property of Kongsberg Oil & Gas Technologies

Instrumentation on LMRP

25

Motion sensor Kongsberg MRU5+

Strain sensor module

Communication module

Battery pack

All pictures are the property of Kongsberg Oil & Gas Technologies

The measured data is transmitted to land in

real-time for further processing

21/05/2013 WORLD CLASS - through people, technology and dedication.

Example of a history plot. Example of a control dashboard.

All pictures are the property of Kongsberg Oil & Gas Technologies

Summary … on riser and wellhead monitoring for drilling operations

• The critical parameters during a drilling operation are:

• Upper flex-joint angle,

• Lower flex-joint angle,

• Telescopic joint stroke,

• Top tension.

• Exceeding operation limits for critical parameters may cause damage.

Introduction

• Real-time sensors used with an advanced model provides the states of the riser system to the operator.

• Critical parameters are continuously watched and action taken if operation limits are exceeded.

• The purpose is to avoid damage.

Operational monitoring

• Optimize the operation and reduce the risk of undesired events.

• Vessel repositioning can reduce the critical parameters.

• The purpose is to assist the operator and reduce the risk of damage.

• The optimization may also reduce the vessel down time.

Advices and decision support

• Instrumentation of the riser and BOP to measure loads on the wellhead.

• Calculate the wellhead fatigue in real time based on the rig actual motion and riser / BOP behaviour.

Wellhead fatigue

kongsberg.com

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