挪威海德罗公司油气井完整性

Well Integrity within Norsk Hydro

Objective

●Develop a consistent procedure for

management of annular leaks

●Risk based approach

●Routines for early detection and how to

handle the leaks

●Procedure made in collaboration between

NH, Exprosoft and Kåre Kopren(PTG)

●Key items in the procedure:

●Include detection, diagnosis, assessment and responses to well annular leaks

●No increase in installation risk (QRA modelling)

●Specific risk reduction measures

●Variations in risk level (subsea vs. topside, gas vs. oil, etc.)

●Applicable to all well types operated by Norsk Hydro

●In compliance with regulations and standards

Principles

●

Overview of well data and limitations shall follow the well throughout the lifetime

●

All leaks shall trigger an internal deviation (synergi) –verification in B&B

●Well data shall be updated when a leak is detected

●Checkout of integrity of next casing

●

Test program to identify leak above or below BSV, surface pressure after stabilizing of pressure, leak rate

●Update of well risk level, based on Wellmaster database

●

Update of operational procedures

WOCS

To The Cutting's Disposal System

AMV AVV ACV

BMV

AWV

XOV SIV SIT

P

MBS

Production

Scale Inhibitor Methanol

Flow -line connector

PCV

PWV SCV

PMV

P

Sliding sleeve

Flow control valves

Retrievabl e isolation packer

Side mounted guns

Gas cap gas lift screen and gas lift valve

Pressure gauge DHSV

Retrievable

production packer

Clean out valve

Screen with ECP and

radioactive tracer

Status procedure for management of well annular leaks

●Procedure is finished

Remains:

●Implementation

●Training of offshore personnel to detect leakages + diagnostic work

● A pilot course has been held in april.

●Standard course package will be developed based on the experience

from the pilot course

●All personell involved in detection and diagnostic work offshore and

onshore will be invited

Historical Norsk Hydro downhole annulus well integrity (WI) issues by field

Note: Based on Norsk Hydro WellMaster phase V data (Snorre and Visund currently Statoil), last major database update April 2004

Figure shows “Cumulative #Annulus WI Issues / Cumulative #Completions” by Year

Field 1995199619971998

199920002001200220032004BORG 0.0 %0.0 %0.0 %0.0 %

0.0 %0.0 %BRAGE

0.0 %

0.0 %

7.4 %

9.7 %17.6 %60.4 %57.9 %54.7 %

60.0 %59.1 %FRAM VEST 0.0 %0.0 %0.0 %GRANE 0.0 %

0.0 %12.5 %NJORD

0.0 %0.0 %16.7 %12.5 %35.3 %44.4 %47.4 %47.4 %OSEBERG B 2.9 % 2.6 % 2.3 % 2.0 % 1.9 % 1.8 % 6.6 %8.1 %7.5 %7.4 %OSEBERG C 0.0 %0.0 %0.0 % 3.0 % 6.1 % 6.1 % 5.4 % 5.0 %

5.0 % 5.0 %OSEBERG S 豏0.0 %0.0 %9.1 %14.3 %

11.1 %10.5 %OSEBERG VEST 0.0 %

0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %

0.0 %0.0 %OSEBERG 豐T 75.0 %27.3 %20.0 %21.1 %

25.0 %25.0 %SNORRE 0.0 %0.0 %

1.6 %

1.5 %

2.6 %

3.5 %7.5 %8.1 %

8.1 %8.1 %SNORRE B 0.0 %0.0 %

0.0 %0.0 %TOGP 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %TORDIS 0.0 %14.3 %14.3 %12.5 %11.1 %11.1 %10.0 %10.0 %10.0 %10.0 %TWOP 0.0 %0.0 %0.0 %

0.0 % 4.2 %8.0 %7.7 %39.3 %39.3 %37.9 %VARG 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %VIGDIS 0.0 %

0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %VISUND 0.0 %0.0 %0.0 %0.0 %0.0 %10.0 %10.0 %10.0 %Total

0.7 %

1.1 %

2.5 %

3.0 % 6.3 %12.4 %1

4.6 %16.7 %16.9 %

17.0 %

0.0 %

5.0 %10.0 %15.0 %20.0 %1995

1996

1997

1998

1999

2000

2001

2002

2003

2004