Standardizing Completion & Workover Riser Assessments · completion/workover riser (CWOR) assessments: Provide a consistent methodology Provide consistent results presentation Allows

Standardizing Completion & Workover Riser Assessments

Tze King Lim, Jia Hui Lee, Hugh Howells

19th February 2014

Learn more at www.2hoffshore.com

Agenda

Objectives and introduction

Data collation

Consistent analysis methodology

Consistent results presentation

Evaluation of new applications

Verification by usage tracking

Conclusions


CWOR Challenges

Equipment used on and off for 20 years, with changes in:

Vessels

Equipment configuration

Field location and water depth

Personnel

More limited operating environments than drilling risers

Wide range of equipment from different vendors

Inconsistency in response evaluation and definition of usage limits


Objectives

To address lack of standardization in completion/workover riser (CWOR) assessments:

Provide a consistent methodology

Provide consistent results presentation

Allows better decision making and project management

To provide a consistent approach to evaluation of new applications:

Assess if previous assessments are still applicable

Avoid unnecessary analysis

To provide cost savings


CWOR Operability Assessment

Equipment specification and configuration

Vessel interfaces

Vessel positioning and environmental envelopes

Fatigue assessments – wave and VIV

Installation and intervention envelopes

Open water and marine riser modes

Usage and fatigue tracking

(

Fixity in all degrees of freedom

Current

Wave

Pitch / roll

Heave

Surge / sway

Surge /

sway

Tension to support

Varies in extent, methodology and presentation of results between projects


Inputs

Drilling Vessel

Riser System Coiled

Tubing/WO

Functional Requirements

Metocean Data

RISER ANALYSIS

Obtaining data from various sources can be challenging Learn more at www.2hoffshore.com

Wide Ranging Riser Inventory

Riser Production

Bore (inch)

Annulus Bore

(inch)

Connector Type

Pressure Rating (psi)

Water Depths

Deployed (m)

1 5-1/8” 2-1/16” Union Nut 10k 80

2 5-1/4” - Drill Pipe 10k 540

3 5-1/8” 2-1/16” Dog 10k 390 - 410

4 7-1/16” - Union Nut 10k 830

5 7-1/16” - Union Nut 5k 70 - 130

6 5-1/8” - Union Nut 10k 420 - 600

Planning to use Riser 5 at new field. New assessment required? Learn more at www.2hoffshore.com

Components

Multiple components with many variations Learn more at www.2hoffshore.com

Steps for Standardized CWOR Assessments

Data collation

Consistent analysis methodology

Consistent results presentation


Verification by usage tracking


Data Collation

Data dossier – live document, single reference source for all input data

Links in dossier to all reference documents

Consistent data sets in simple, easy to read tables

Data Dossier

Completion Riser Data

Marine Riser Data

Metocean & Soil Data

Drawings

Analysis Reports

Operational Logs

Vessel Data Maintenance Records


Example Compiled Riser Data

Riser Joint Length Weight in Air Weight in

Water Outer Diameter Internal Diameter Yield

Stress

ft m lb kg lb kg in m in m ksi

Standard Joint 45.000 13.716 3318.5 1505 2885.2 1308 8.622 0.219 7.374 0.187 80

Tension Joint 15.846 4.830 3869.8 1755 3364.5 1526 9.646 0.245 7.165 0.182 80

10ft Pup 10.000 3.048 1378.1 625 1198.2 543 8.622 0.219 7.374 0.187 80

25ft Pup 25.000 7.620 2304.2 1045 2003.4 909 9.646 0.245 7.374 0.187 80

CWJ Thick Pipe Section

38.780 11.820 4617.6 2094 4014.6 1821 8.622 0.219 7.165 0.182 90

CWJ Thick Wall Section

4.035 1.230 480.5 218 417.8 189 9.606 0.244 7.173 0.182 90

CWJ Thin Wall Section

5.741 1.750 683.6 310 594.4 270 9.055 0.230 7.165 0.182 80

THRT 4.921 1.500 2335.1 1059 2030.2 921 18.504 0.470 7.047 0.179 80

THOJ 9.793 2.985 5957.9 2702 5177.3 2348 18.504 0.470 7.047 0.179 80

Riser Adapter 3.520 1.073 389.6 177 338.7 154 8.976 0.228 7.165 0.182 80

Overshot Adapter 2.395 0.730 1280.0 581 1112.9 505 18.110 0.460 9.370 0.238 80

Shearable Joint 13.645 4.159 1069.2 485 929.6 422 8.622 0.219 7.165 0.182 80

Annular Slick Joint 4.921 1.500 1435.5 651 1248.0 566 11.260 0.286 7.165 0.182 80

Adapter 17.060 5.200 1808.1 820 1572.0 713 8.898 0.226 7.165 0.182 80


Consistent Analysis Methodology

Boundary conditions – types of fixities to wellhead and vessel

Calculation of section properties

Tension calculations

Vessel positioning and environmental envelopes

Fatigue performance – wave and VIV

Installation and hang-off limits

Ensures easier understanding and comparison of results Learn more at www.2hoffshore.com

Consistent Results Presentation

Coloured areas provide indication of allowable heave and offsets


Operating Manuals

Concise document for operational guidance offshore

Main contents:

Glossary and Definition

Riser Stackup

Tension Requirement

Operating Limits

Limit

With CTF

With Surface Equipment

Without Surface Equipment

0 psi 5000 psi 0 psi 5000 psi

Allowable Maximum Wave Height (m)

6.2 6.2 6.8 6.6

Allowable Downstream Vessel Offset, No Waves (%)

-10 (-83m)

-8 (66.4m)

-10 (-83m)

-8 (-66.4m)

Allowable Upstream Vessel Offset, No Waves (%)

6 (49.8m)

6 (49.8m)

6 (49.8m)

6. (50.6m)


Evaluation of New Applications

A change evaluation is performed to determine:

Are previous results still applicable?

Are new analyses required?

If yes, what types of new analysis are required?

Level of change allowed is assessed based on experience

Sensitivity analysis performed to verify recommendations of change evaluation


Change Evaluation - Water Depth

5-15% change requires:

Reassessment of wave-induced and VIV fatigue

15-25% change additionally requires:

Tension requirements to be reassessed

Operating envelopes analysis

>25% change additionally requires:

Repeat of installation analysis


Change Evaluation - Vessels

Vessel RAOs

Change in magnitude or period of RAO peaks requires repeat of dynamic analyses

Drill Floor Elevation

If change >10m, reassess operating envelopes and equipment passage limitations

Moonpool Size

Reassess operating envelopes if limited by moonpool clashing


Implications of Other Changes

Parameter Required New Analysis

Extreme waves and currents Operating envelopes, installation, hang-off, equipment passage

Long-term waves and currents Fatigue analysis

Soil stiffness Marine riser mode analysis

Internal fluid density or pressure Operating envelopes

Tree/EDP/LRP size and weight Installation and hang-off analysis

Riser base tension Operating envelopes and fatigue

Surface equipment weight Operating envelopes and fatigue

Marine riser joints, BOP/LMRP stack Marine riser mode analysis, equipment passage


Integrity Management

To track CWOR performance over time & verify analysis results

Perform risk assessment for each component based on failure modes, likelihood & consequences

Identify critical components

Develop inspection and monitoring plan

Visual surveys

Weld inspections

Recording weather and operations

Monitor movement of riser

Data Dossier

Inspection &

Monitoring

Change Evaluation & Analysis

Risk Assess-ment


Verification by Monitoring

Case study of using strain monitoring

Used to track fatigue accumulation at upper stress joint

Fatigue extrapolated to cased wear joint (most critical location)


Woodside Pluto, WoosidePluto 2009 12 04 12 22

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Riser Response Measurements

Frequency peaks indicate motions are driven by 8-12s waves

Time history Frequency spectra Learn more at www.2hoffshore.com

Fatigue Tracking

Component

Fatigue Life from Global

Analysis (years)

Calculated Fatigue Life from

Measurements (years)

USJ 288 1066.9

CWJ 1.39 11.7


Conclusions

CWOR operation management is challenging due to:

Varying operating conditions, equipment and personnel

Occasional usage over many years

A consistent approach can be implemented through standardization of:

Data collation

Analysis methodology

Results presentation


Consistency allows for more reliable long-term riser management and cost savings


Questions?

Further information:

2H Offshore Engineering

www.2hoffshore.com

+61 8 9222 5000


http://www.2hoffshore.com/


http://www.2hoffshore.com/

Documents

Standardizing Completion & Workover Riser Assessments · completion/workover riser (CWOR) assessments: Provide a consistent methodology Provide consistent results presentation Allows