31_well design workflow

Copyright 2009, NExT, All rights reserved

Well Design Workflow


Objectives

At the end of this training session, you shouldbe able to:

List and Describe the 3 phases of the well design process– State the 7 Design Modules of the Well Design phase

• Describe the 7 Design Modules– Explain what we monitor in the Execution phase– Explain why we evaluate performance in the Evaluation phase


Outline

3 Phases of the drilling engineering processPhase 1: Well Design– Design ModulesPhase 2: Well ExecutionPhase 3: Well EvaluationSummary


Engineering Process

Phases

Evaluate Design

Execute


Phase 1: Well Design


Key Elements of Well Design

Standards, Policies and ProceduresDE responsibility to adherence for deliveryEngineering Standards (API)Policy manuals– casing design– well control– surveying including anti-collisionProcedure manual or guidelines– drilling operations– directional


Well Design Process Flowchart

Well Design Flowchart

Obtain wellrequirements Data transfer procedure

Input & validate

Obtain specialdata for field Input & validate

data sets

Data transfer procedure

This phase of theprocess is dataacquisition andvalidation from

the client. Theremust be a recordmaintained of this

transfer toSchlumbergerObtain lithology,

fracture and porepressure data Input & validate

data sets

Data transfer procedure

There must be designstandards for :

ConductorSurface Casing

Intermediate CasingsProduction CasingProduction Liners

DesignCasing

Pressurecontainment?

Yes

No

Well lifeconsiderations

?

No

Yes

TrajectoryDesign

TrajectoryDesign

Select HoleSizes to

deliver CasingDesign

Determine profileconstraints:

surfacereservoir

wellbore stability

SurfaceCollision Risk ?

SurveyProgramme

Design

Well PlanWell Plots

Yes

NoCan

better SurveyProgramme remove

risk?

Yes

No

Areall well

positionalrequirements

met?

No

Well drilling plan

CementingDesign

Drilling Fluid

Confirmlegislation

requirements

Select MW frompore pressureand wellbore

stability

Drilling Fluidprogramme

T&D, Casing Wear andHydraulic study OK?

No

Completed WellDesign

Yes

MW andFrictionFactors

Drillingsystemdesign

Select bitand systemcombination

Design BHAdetails to giverequired DLS

Design Drillstring

Bit/BHA strategywith drillstring

Drillstringand BHA

Select TOCfor each holesection fromLOF basis

Determine TOTCfor isolationpurposes

Determinevolumes preflush,

spacer andcements then

produce pumpingschedule

Get specialistcontractor to

formulaterecipes

Cementingprogramme


Well Design Process

Casing Design

Data Gathering&

Validation

Trajectory Design

Survey Programme Drilling Fluids

Drilling SystemDesign

CementingDesign

CompleteWell Design

Start Finish

1

7

2 Re-iterate if needed

6

3 4 5


Design Module 1

Data Gathering– Requires checklists – Requires client confirmation – Requires SLB QA


Key Elements of Data Gathering

Data gathering and validation– checklist with client to gather data consistently– review results with client to confirm– demonstration of data used is vital to QA/QC process

• DE Checklists• Planning checklists• Positional accuracy• Internal sign off


Design Module 2

Casing Design– Safety critical– Process must be formally recorded in a ‘Basis of Design’– Engineering involvement through Kick simulations, casing

wear affect on pressure ratings, running (T&D) and casing flotation


Key Elements of Casing Design

Casing Design (including couplers)– Size range available with delivery times– Structural to take wellhead and environmental loads– Surface aquifer isolation to prevent pollution– Pressure containment– Kick tolerance– Metallurgy– Bending loads– Wear allowance– Burst / Collapse / Tensile safety factors


Design Module 3

Trajectory Design– Well Plans produced according to a design process– ‘Basis of Design’ document detailing why selections have been

made.– Record of learning incorporated into BoD


Key Elements of Trajectory Design

Trajectory Design– Surface collision avoidance– Dogleg limitations– Formation responses– Reservoir orientation and placement– Availability of tools to deliver profile ???


Well Surveying and AC Policy

Applies globally to all aspects of Survey Management– Includes survey data and database management– Geometric well trajectory planning– Survey Quality assuranceIt will be strictly followed except in the case where:– An established client policy with a higher safety threshold

exists and is implemented– Where a written exemption is granted by the appropriate

authority


Policy Responsibilities

Local Engineering manager – Responsibility for all well design activity, including SM– Responsible for technical integrity of any well design– Primary sign off authority Line Management– Ultimate accountability– Final signature on the well planMandatory for final well design delivered to client, sign off by:– Originator, DEC sign-off authority, D&M line mgt, client


Classification of Well Types

Trajectory Planning Design– All wells classified as either “single” or “nearby wells”After global scan of definitive database if no other well within30,000 meters of its surface location– Treat as a single wellAll other wells classified as nearby wells


Design Module 4

Survey Programme– The planned series of instruments to be used, surveying

requirements to be met during the execution of the well designProgramme designed to provide in the most cost effective and safe manner:– Achieve target sizing– Well position uncertainty for:

• Relief well purposes • Anti-Collision


Design Module 4

Survey Programme– Drilling Target Size

• Geological target reduced by an amount representing the survey errors

– Close approach• Approved anti-collision policy and process, referencing the

correct ‘part’ of the programme at all depths– Redundant principle of survey program design– Survey Contingency Planning– Approved Error models


Key Elements of Survey Design

Policy– redundant principle or exemption from clientClient– review their policies– confirm our software can manage client policyInstrument Error– rank preference (ISCWSA, Topographic, WdW, Simple)– understand 3d, 2d, 1d– understand sigma value



Design– parts; correct part used for anti-collision at the right depths– what constitutes the definitive surveyOperation– instruments performing to specification– instruments run to programmed depths– contingency if hole deteriorates



Quality– every survey is QA/QC’d– MWD is surveying– evidence is kept that tools have met performance criteria– failures are fully investigated– root causes of failures are identified– aim to GUARANTEE the definitive survey


Design Module 5

Fluids Programme– Not internal to Oil Co normally– Major impact on T&D, hydraulics– Wellbore stability

• Not just hydrostatic pressure– Impact on downhole drilling systems


Key Elements of Fluid Design

Drilling Fluid Design– Environment– Density > pore pressure and < fracture pressure– Rheology (hole cleaning and ECD)– Inhibition– Formation damage– Lubricity– Cost


Design Module 6

Drillstring design and considerations– Integrity– T&D, hydraulics– Tapered strings– Rig capacity and sizing– ECD


Key Elements of Drilling System Design

Drilling System Design– Maximise efficiency– Select right bit for each system– Process will identify critical components– Process will identify critical measurements– Accuracy of measurements will be specified– Drillstring design


Design Module 7

Cementing Design– ‘Basis of Design’ document detailing why selections have been

made.– Record of learning incorporated into BoD– Practical involvement through drillouts (bit/BHA) sidetracking,

loss control, drillstring contamination


Key Elements of Optimisation

Design Optimisation– Torque– Drag– Hydraulics– Casing WearIterative approach– if a problem arises we must have sufficient knowledge to

understand the problem before attempting to resolve it


Well Execution Flowchart

Identifyprocess to

monitor

Data StoredData

recorded Data QA/QC'd

Reports

Is plan beingachieved?

Yes Is Datarecorded ?

No

Yes

No

Is allowabledeviationfrom plan

quantified?

Yes

No

Can plan bemodified within

limits?

Modify andinform ALL

partiesYes

No

Re-engineerfrom currentposition tonext target

Haltoperations

Normal QA/QCprocess to record

changes andlessons learned

Release newplan to ALL

parties

Non-ConformanceReport issued


Well Execution

What do we monitor ?– Well integrity

• Casings on depth and sufficient kick tolerance to finish section– Deviation

• No collision issues• Can still get to target within Inc, Azi and DLS limits and driller’s

target still valid– Survey Programme

• All instruments perform to specification• All instruments are run to programmed depths


Well Execution

What do we monitor ?Real time? – BHA performance

• Delivers expected DLS• Drills in time and cost effective manner

– Bit performance• ROP is as expected or better

– Mud• properties are within specification

– Logistics• All equipment for the well is available within delivery schedule


Well Evaluation Flowchart

ProcessEvaluation

Review metricsfor each processDo performance

metrics exist ? Yes

No

Is theperformance of thisprocess assessed?

Yes

NoReport factual data

Data GatheringReview times to obtain dataReview data accuracy

Casing DesignCasing seat selection satisfactoryCasing w ear satisfactory

Trajectory DesignProfile drillableTorque and Drag predictionvalidation

Survey ProgrammeInstruments performanceQA/QC reports w rittenService performance

Drilling System PerformanceDLS w ithin criteriaWellbore tortuosity / Dif f icultyBit Selection review

Drilling FluidProblemsEnvironmental lossCost

CementingProblemsEnvironmental lossCost

Operations ReviewNon Productive Time and Cost

FailuresEff iciency review

Ft/Day$/Ft

LogisticsEff iciency review

Prepare metrics torepresent relevant

performance


Well Evaluation

Why do we evaluate ?– To understand what happened– To improve our performance next time– To keep our customers satisfiedWhat do we evaluate ?– Metrics– Deviations from applied limits– Difficulty


Summary

The 3 phases of the drilling engineering process are:Design – Execute – Evaluate

There are 7 Design modules in the Design Phase:1. Data Gathering2. Casing Design3. Trajectory Design4. Survey Programme5. Drilling Fluids Design6. Drilling System Design7. Cementing Design


Analysis of Offset Wells

The main objectives of the offset well analysis are:– Identify all problem areas – Identify all events – Identify all good practices– Provide the necessary information to conduct a risk analysis– Measure performance for benchmarking– Identify constraints and areas of opportunity– Validate assumptions


Relevant Offset Well

Guidelines for the identification of relevant offset wells:– Pick wells all around the target location– Pick the closest wells available– Old wells contain valuable information (original pressures,

drilling hazards, etc)– Recent wells are better for time analysis, bit selection, existing

pore pressure, etc.– Wells in close proximity to the new well but in different

structures or separated by faults can still yield valuable information

– Ideally, we are looking for geological similarity combined with geometrical similarity


What Data Should be Reviewed?

Daily operations reportsDrilling fluids, cementing, casing reports.Composite log (mud loggers log)Drilling data Log (MD Totco, 6 pen geolograph, etc.)Open hole logs (e.g. Caliper, Gamma Ray, Resistivity, Neutron

Density, Sonic, etc.Cased hole logs (CBL-VDL, USIT, multi-finger calipers, etc.)Structure map showing location of offset wells (surface and subsurface) and location of proposed wells


What Data Should be Reviewed?

Field map showing location of existing roads and existing padsEnd of Well ReportsSeismic sectionsBit RecordsPore and Frac pressure profilesTemperature Profiles


Benchmarking and KPI’s

Requirement to benchmark against offset dataTechnical Limit Drilling

• Actual Time = Technical Limit + Waste (20-40%) + NPT(10-15%)

The Technical Limit is what could be achieved in a flawless operation using the best possible people, planning and technology


Key Performance Indicators - KPIs

What are KPI’s– An analytical (metric) but continuous assessment of

performance at multiple levels within the organisationExists from the share holder to the bit!

Examples – non oilfield– GNP (Gross National Products)– Capita per head (measure of wealth)


Performance Measurement Examples of Key Performance Indicators (KPI’s)

Days/10,000’Days/completion$ / Ft, ft / $$/completionQuartile rankingNPT for drlg/completion% NPT improvement% Flat time / drilling time$/BoeWell complexity

Days to top reservoirFootage per BHAFootage per dayFootage per 1000 circ hrNPT (contractors equipment, WOW)NPT/1000 ftNPT per 1000 circ hrEfficiency evaluationSlide/rotate ratios


Analysis T - Plots

Inclination T-plot

0

1000

2000

3000

4000

5000

6000

70000 20 40 60 80

Inclination (deg)

Mea

sure

d D

epth

(m)

Planned inc As drilled inc

Azimuth T-plot

0

1000

2000

3000

4000

5000

6000

70000 100 200 300

Azimuth (deg)

Mea

sure

d D

epth

(m)

Planned azi As drilled azi


Analysis T - Plots

Dogleg T-plot

0

1000

2000

3000

4000

5000

6000

70000 2 4 6

Dogleg (deg/30m)

Mea

sure

d D

epth

(m)

Planned dls As drilled dls

Tortuosity T-plot

0

1000

2000

3000

4000

5000

6000

70000 50 100 150 200

Total Curvature(deg)

Mea

sure

d D

epth

(m)

Planned tort As drilled tort


Conclusions

So, now you should be able to:

List and Describe the 3 phases of the drilling engineering process– State the 7 Design Modules of the Well Design phase

• Describe the 7 Design Modules– Explain what we monitor in the Execution phase– Explain why we evaluate performance in the Evaluation phase


End of Module

31_well design workflow

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