Managing integrity of large volumes of wells volumes of wells

By Paul Hopmans By: Paul Hopmans Well integrity principal technical expert expert Shell Projects & Technology

Copyright of Royal Dutch Shell plc

Managing well integrity of large number of wells

We currently manage the integrity of some 15,000 wells using Shell developed system ,called eWims.

We manage the wells in accordance to the latest standards that are available with in latest standards that are available with in Shell and industry.

Validation of as build is an ongoing project Validation of as build is an ongoing project that will confirm well operating envelops.

Management of internal & external corrosion with changing operating conditions is a challenge.

What will change with CO2 sequestration?

eWims Well Integrity Management System

eWims is a system that handles 15,000 wells Allows you to manage / overview the status of your wells on.

Preventive maintenance tasks Corrective maintenance tasks Annular pressure monitoring Blow down and top up Conductor inhibitor Conductor inhibitor treatment External corrosion monitoring Casing load calculation Well head growth / Well head growth / subsidence Trigger pressures alarms Production data upload Maasp & mechanical Maasp & mechanical data EDM Compliance KPIs Notifications to SAP / FSR Deviations

Well Integrity in design requires that

Operating conditions are defined

Physical behavior is

Operating envelop

Xmas tree and well head pressure rating Physical behavior is

modeled and analyzed Functional failure modes

are considered

pressure rating and ESD test criteria.

Know your

Safety critical elements are identified

Performance standards of

Annulus Maximum allowable surface pressure (MAASP )

safety critical elements are quantified

SCSSSV test frequency and leak criteria

Know your What are the changes of CO2

sequestration in our design envelop to manage well integrity ?

Know your strength of reservoir ( leak off )

Strength of casing integrity ? simulate strength ( Stress Check)

Strength of tubing simulate stress behavior ( Well

ABC

Risk of CO2 with annular communication

ABC Risk of out flow due to

packer failure or tubing failure that 30

20 Fluidleak-off to

tubing failure that may cause casing internal corrosion and breach around shoe 20 Fluid leakoff to C Annulus

Formation Seepage through

annulus from 13 3/8 Fluid leak-off to

B Annulus Formation

reservoir micro annuli that may corrode casing externally and cause out flow

9 5/8

P d ti

cause out flow

Well collapse due to casing corrosion Production

Tubingcasing corrosion

Risk associated with casing failure jump or slump

Reducing the wall loss through external corrosion can lead to a loss of containment but also to structural failure

Loads are highest in injection wells and when the well cools

Flow line

Loading on S. CsgLoading on S. CsgLoading on S. CsgTbg : + 132PC : + 275IC : + 85

Tbg : + 132PC : + 275IC : + 85 Loading on S. Csg

Tbg : + 14PC : + 95IC : -209 !!

As built datum

-511 kipsOn SCsg +190 kips

Surface Casing is now in tension

Top of Conductor

Mud lineOn flowing the casings heats up reducing tensile forces. In this case the load in the IC is

07 May 2010 6

static Prod

the load in the IC is now UP

CO2 sequestration challenges to Well Integrity

Risk of failure due to loss of external casing barriers (CO2 leak and poor cement bonds)

Industry field reviews for CO2 sequestration have demonstrated that we may have not constructed our wells or abandoned them in view of for CO2 sequestration.

Risk assessment in changes to well operating envelop for CO2 sequestration is being debated no clear for CO2 sequestration is being debated, no clear standard (DNV is working a proposal in a JIP)

Iso standard proposal via OGP in preparation supported by the major operators to address wells lifecycle by the major operators to address wells lifecycle integrity in operate phase

Well integrity management standards & systems are not inclusive of CO2 sequestration risks.

Check list when you change a well to CO2 injectorCO2 injector

Casing and tubing and tubing accessories and wellhead (such as packer, flow control nipples, SCSSV, etc) all ( , , , )meet CO2 materials spec?

Casing and tubing system meet injection pressure requirements - Well cat has been modeled? requirements Well cat has been modeled?

Confidence in cap rock and cement seal for the reservoir pressures expected during injection?

Testing can be done to confirm this in the near well bore region (tracer injection tests, temp logs, etc.)

Cement integrity confirmed and type of cement used on production casing.

CO2 ratios are important to know for both cement integrity and material corrosion integrity and material corrosion.

Check list when you change a well to CO2 injector

Casing design i.e. material compatibility, from field perspective - like we have seen with upper and lower intervals separately explored

Wellheads, and xmass tree, seals and feed through - check compatibility for CO2, may have to flush valves with specific grease. Check with wellhead manufacturer

Pressure gauges transducers and other threaded Pressure gauges , transducers and other threaded & fitted components to well need to be checked for CO2 compatibility

Wellhead control panel needs to be checked for Wellhead control panel needs to be checked for CO2 compatibility as flow back from control line can enter and hit panel.

Annular monitoring in event of annular communication problems - are there current existing sustained annulus pressures and have