3 Kick

Page 1 of 63GEOSCIENCES AND PETROLEUM ENGINEERING DEPARTMENT, Modern Well Design

“Modern Well Design”

Drilling Engineering

GEOSCIENCES AND PETROLEUM

ENGINEERING DEPARTMENT

06/December/2011 14:00 – 16:00 &

07 Dec (10:00 – 12:00)


GEOSCIENCES AND PETROLEUM

ENGINEERING DEPARTMENT

MODERN WELL DESIGN

(06, 07 Dec “10:00 – 12:00”)

ADVANCED CASING DESIGN

(07 Dec “14:00 – 16:00”, 08 Dec “10:00 – 11:00”)

ADVANCED DRILLSTRING DESIGN

(08 Dec “14:00 – 16:00”, 09 Dec “10:00 – 11:30”)

Seminar Room 6, Undercroft, UTP


Objective

At the end of this course, the attendants should be able to answerthe following questions?

What does the profession of Drilling Engineering mean?How can a well design be initiated?What offset well information to be collected?What is kick tolerance, how is it calculated?How can a kick be identified?What is an AFE, how can it be calculated?What is a bit record, how can the bit cost comparisons bemade?Cementing, operations sequences?What are the practical information in a drilling process?Drillstring design, is it difficult?

It is assumed that the attendants are familiar with subjects which may have beenstudied prior to this course as given below:

Introduction to Petroleum & Natural Gas EngineeringBasic Engineering courses


Outline

Drilling EngineeringWell DesignRig RequirementsDrilling PlanningOffset WellsKick ToleranceKick IdentificationAFEBit Record/CostCementingPractical InformationDrillString DesignConclusionBackUp Slides


The goals of the drilling engineerinclude:

providing accurate costestimates,designing well programs thatsatisfy well objectives,reducing cost through theselection of high-efficiencyequipment, systems, andpractices,ensuring safety through therecommendation of soundpractices and through contingencyplanning.

Drilling Engineering


Responsibilities of a DRILLING ENGINEER

The drilling engineer plays a number of roles in the well planning process.During initial evaluation of a prospect, he or she conducts preliminarystudies and estimates well costs. Once well AFEs are approved, thedrilling engineer:

becomes the designer, coordinator, and monitor of the overall wellprogram.

The responsibilities of the drilling engineer include:gathering and reviewing available data on previous drilling activity inthe proposed areas of operation,preparing initial cost estimates,preparing specific well-cost estimates for Authorization for Expenditurepackages,conducting an initial planning meeting with others involved in specificwell projects to establish objectives for the well,estimating expected formation pressures and fracture gradients,anticipating and addressing the most likely drilling problems,selecting casing sizes and setting depths,providing the data necessary for submitting an application for a drillingpermit,

Drilling Engineering (Cont’d)


resolving directional drilling requirements,developing the drilling mud program,designing casing strings,preparing a hydraulics program,recommending bottomhole assemblies and bits,preparing cementing recommendations,preparing step-by-step procedures for drilling operations,preparing rig specifications prior to rig bid requests to assist in rigselection,identifying necessary mud-processing and solids-controlequipment,preparing drilling-cost and drilling-time curves to plot predictedperformance,coordinating the well-planning activities of geoscience, purchasing,operations, environmental and regulatory and other engineeringgroups to ensure that all aspects of well program development willmeet schedule commitments.

Drilling Engineering (Cont’d)


Well Design - Objectives

Proper planning is key to optimizingoperations and minimizingexpenditures.The drilling person’s job is to developoil and gas reserves at minimumcost.

Oil companies are in the businessto make money,If the organization do not makemoney, it cannot stay in business.

The first step in formulating anydrilling plan is to gatherinformation for drilling the well.The selection of casing settingdepths is critical for casing offtroublesome formations, containingpressure, or protecting fresh waterformations.


Rig RequirementsThe drilling is achieved by means ofhaving properly selected the followingmain items of the rig components:

Power Generation System,Hoisting System,Fluid Circulation System,Rotary System,Well Control System,Drilling data acquisition andmonitoring system.

Other considerations for RigSelection:

Safety Records,Rig mobility and ease ofhandling,Contractor Dependability.Contractual rates (footage, day,turnkey),Condition of all rig equipment.


Drilling Planning

The drilling engineer is the well architect and planningcoordinator for the drilling project, he/she is in charge of:

Collecting and revising available data for all offset wells,Designing all of the drilling programs (drilling fluid, bit,hydraulics, casing/cementing/ directional drilling, tubulars,BHA and well control aspects),Preparing the AFE (Authorization for Expenditures),Foreseeing the drilling problems, preparing contingencies,Selecting drilling rig and specifications,Preparing drilling cost vs time curves,Preparing and organizing the tenders related to rig andservices,Preparing and organizing the purchasing of the long-leaditems,Making sure that the environmental, regulatory and otherengineering group objectives are met, and the wellprogrammes are executed economically, safely and onschedule.


Offset Wells’ InformationBest information source for effective Well Planning is collecting informationfrom the offset well data.The following information is of paramount importance:

Daily Drilling Reports,Hydraulics Reports,Tubular Reports,Mud Reports,BHA (Bottom Hole Assembly),Directional Surveys,Drilling Bit Records,Electric Wireline Loggings,Casing and Cementing Reports,Geological Information,Reservoir Characteristics,Logistics,Weather conditions,Service Company recommendations,Government Regulations,Problems Encountered,Success and Failed Reports of the attempted solutions for the problemsoccurred.


MJ-2

GroundHammar

Upper Fars - Dibdiba

Lower Fars

Ghar

Damman

Um Er-Radhuma

AalijiShiranish

Hartha

Sa'di

Tanuma

Khasib

Mishrif

Rumalia

Ahmadi

Mauddud

Nahr Umr

Shuaiba

Zubair

Ratawi

Yamama

TD

42" CP

30" CSG

20" CSG

13 3/8" CSG

9 5/8" CSG

7" Liner

ML (Minor) Start

ML (Minor) End

ML

ML Severe (Gas Kick)

Water Ingression

MJ-3

GroundHammar

Upper Fars - Dibdiba

Lower Fars

Ghar

Damman

Um Er-Radhuma

Shiranish

Hartha

Sa'di

Tanuma

KhasibMishrif

Ahmadi

Mauddud

Nahr Umr

Shuaiba

Zubair

Ratawi

Yamama

SulaiyTD

30" CSG

20" CSG

13 3/8" CSG

9 5/8" CSG 7" Liner

4 1/2" Liner

Partial ML

Partial ML

Partial ML

Stuck Pipe

Collapse (9 5/8in CSG)

Well Deviated

MJ-4

GroundHammarUpper Fars - Dibdiba

Lower Fars

Ghar

Damman

Um Er-Radhuma

Aaliji

Shiranish

Hartha

Sa'di

Tanuma

Khasib

Mishrif

RumaliaAhmadi

Mauddud

Nahr Umr

Shuaiba

Zubair

Ratawi

Yamama

TD

30" CSG

20" CSG

13 3/8" CSG

9 5/8" CSG

7" Liner

MJ-5


Lower Fars

Ghar

Damman

Um Er-Radhuma

Aaliji

Shiranish

Hartha

Sa'di

Tanuma

Khasib

Mishrif

RumaliaAhmadiTD

20" CSG

13 3/8" CSG

9 5/8" CSG

7" Liner

ML

Water Ingression

MJ-6


Lower Fars

Ghar

Damman

Um Er-RadhumaAaliji

Shiranish

Hartha

Sa'di

TanumaKhasib

Mishrif

RumaliaAhmadi

TD

20" CSG

13 3/8" CSG

9 5/8" CSG

7" CSG

ML (Total)

ML

Deviation Start

Deviation End

MJ-7


Lower Fars

Ghar

Damman

Um Er-Radhuma

Aaliji

Shiranish

Hartha

Sa'di

TanumaKhasib

Mishrif

RumaliaAhmadiTD

30" CSG

20" CSG

13 3/8" CSG

9 5/8" CSG

ML

ML (Total)

Overpull (50 tons)

Gas Cut Mud

Caving (Start)

Caving (End)

MJ-8


Lower Fars

Ghar

Damman

Um Er-Radhuma

Aaliji

Shiranish

Hartha

Sa'di

TanumaKhasib

Mishrif

RumaliaAhmadi

Mauddud

Nahr Umr

Shuaiba

Zubair

Ratawi

Yamama

Sulaiy

TD

42" CP

30" CSG

20" CSG

13 3/8" CSG

9 5/8" CSG

7" Liner

ML

ML (Stopped)

Fishing

Fishing

Fishing

MJ-9


Lower Fars

Ghar

Damman

Um Er-Radhuma

Aaliji

Shiranish

Hartha

Sa'di

TanumaKhasib

Mishrif

RumaliaAhmadi

Mauddud

Nahr Umr

Shuaiba

Zubair

Ratawi

Yamama

SulaiyTD

30" CSG

20" CSG

13 3/8" CSG

9 5/8" CSG

7" Liner

ML (Start)

ML (End)

ML (Start)

ML (End)

ML (Start)

ML (End)

Stuck Pipe

ML in Cementing

-15

485

985

1485

1985

2485

2985

3485

3985

4485

Dep

th, m

TVD

ss

Collecting Offset Wells’ Information

RT, 0 m

30 in. CP @ 100 m

18 5/8 in. CSG @ 1338 m

16 in. CSG @ 2490 m

7 in. Liner @ 5750 m

Overb

urd

en

Gra

die

nt

Po

re G

rad

ien

t

U.Fars-Dibdiba (sst,sh,ms), 30 m

L.Fars (lst,sh,ms,eva), 909 m

Ghar (sd,lst), 1234 m

Damman (lst), 1338 m

Um Er-Radhuma (lst), 1572 m

Aaliji (lst), 1880 m

Shiranish (lst,sh,ms), 1991 m

Hartha (lst), 2144 m

Sa'di (lst), 2276 mTanuma (lst), 2384 m

Khasib (lst), 2431 m

Mishrif (sh,ms,lst), 2490 m

Ahmadi (sh,ms,lst), 2744 m

TOC 250 m

TOC 1188 m

TOC 5165 m

Rumalia (lst), 2712 m

Mauddud (lst), 2901 m

Nahr Umr (sst), 3079 m

Shuaiba (lst), 3266 m

Zubair (sst), 3417 m

Ratawi (sst,sh,ms), 3705 m

Yamama (lst), 3782 m

Sulaiy (lst), 4144 m

Gotnia (lst,sh,ms, salt), 4425 m

Najmah (lst), 4759 m

24 1/2 in. CSG @ 400 m

MJ-2 DST-1

MJ-2 DST-17

MJ-2 DST-22

MJ-9 RFT

MJ-11 Actual Mud Den


MJ-3 Actual Mud Den

MJ-9 Actual Mud Den



Sargelu (lst,sh,ms), 5169 m

Alan (lst,eva), 5233 m

Mus/Adaiyah (lst,salt,eva), 5315 m

Butma (lst,sh), 5502 m

R-N-172_RFT (Najmah_RFT_PP-Gradient)

R-N-172_LOT

Mishrif

Yamama

Gotnia

Najmah

20" CSG_R-N-172

13 3/8" CSG

9 5/8" CSG

7" Liner

Hartha

Cmt (LC) Top

Cmt (LC) Btm

TOC 2340 m

TOC 4609 m

13 3/8 in. CSG @ 3783 m

9 5/8 in. CSG @ 5315 m

Kuwait-Frac

11 3/4 in. Liner @ 4759 m

TOC 3633 m

0

250

500

750

1000

1250

1500

1750

2000

2250

2500

2750

3000

3250

3500

3750

4000

4250

4500

4750

5000

5250

5500

5750

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4

Dep

th, m

TV

DR

T

Pressure Gradient [kgf/cm2 / 10 m]

NEWFIELD-TRIASSIC_WELL PPFG Graph (All depths are referenced to RT= 0 m).


Prior to designing casing strings,the engineer must study pressurerequirements and prepare a mud-density schedule.

A plot of fracture gradient versusdepth should be prepared, althoughin some instances knowledge of thefracture gradients at the casingdepths under study is sufficient.

Leakoff data on new wells isparticularly valuable.

Hole problems must be thoroughlyidentified and the need to designfor acid gases or other corrosionproblems evaluated.

Prior Design


Kick Tolerance

Kick Tolerance is the maximum allowable influx volume, for aknown or assumed SIDPP, which will not cause the formation tofracture when either the influx is at the bottom of the annulus orwhen it is circulated and expanded to the casing shoe by aconstant bottom-hole pressure method.

Maximum tolerable length (H) of gas influx in the annulus at anyposition between bottom hole and the casing:

Where:Hmax = height of gas bubble at casing shoe, ftMW = maximum mud weight for next hole section, ppgTD = next hole total depth, ftCSD = casing setting depth, ftFG = fracture gradient at the casing shoe, ppgPf = formation pore pressure at next TD, psiG = gradient of gas, 0.1 psi/ft


Current well design guidelines prescribe a limit of 100 barrelsminimum kick tolerance for the design of a casing programme.The limit of 100 barrels has been used successfully since itsintroduction in 1986.Recent developments in drilling, such as slim and downsized welldesigns have prompted a reappraisal of the minimum design kicktolerance.These drilling developments have coincided with other analysistechniques that can provide improved kick detection capabilityand through simulation, a better understanding of the behaviourof kicks in the wellbore.For this reason International Oil Companies require their planningpersonnel calculate the Kick Tolerances for all surface andintermediate casing for all well for the defined minimum volumes.For example the minimum kick tolerance for a 12 ¼” hole is 100bbl where as for a 8 ½” hole is 50 bbl. For holes smaller than 8½” the Kick Tolerance is 25 bbl.

Kick Tolerance (Cont’d)


Ref: Practical Well Drilling & Planning Manual

Page 437

in

Pipe OD 5

MAASP Hydrostatic Pressure of the gas

750 psi 54 psi

Formation Pressure Hydrostatic Pressure of Half of the height of the gas

5280 psi 27 psi

Pressure at the top of the gas bubble Annular Capacity

3750 psi 0.121491 bbl/ft

13 3/8" CSG Shoe Depth OH Length Influx Volume

ft 5000 FRAC GRAD 0.75 psi/ft 3000 ft 65.60496 bbl

Pressure in the OH section Pressure in the Centre of the gas Bubble

GAS GRAD 0.1 psi/ft 1530 psi 3777 psi

Mud Grad x OH Length Calculate the volume of this gas at the next casing point

1800 Pressure in the centre of the gas bubble at the CSG Shoe

Gas Influx Length 5253 psi

Hole Size in 12 1/4 540 ft Using Boyle's Law P1V1/P2V2 find the kick Tolerance

Kick Tolerance

47.17 bbl

TD ft 8000 MUD GRAD 0.6 psi/ft

PORE GRADIENT0.66 psi/ft

KICK TOLERANCE







KICK_TOLERANCE__CSG_SEAT_by_Depth_COUNTRY_NEWFIELD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00

Dep

th, m

TV

D R

T

Kick Tolerance, m3

Kick Tolerance Graph

Kick Tolerance, m3 Company Min Kick Tolerance, m3

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0.00 20.00 40.00 60.00 80.00 100.00

Dep

th, m

TV

D R

T

Max Allowable Surf Pres (Choke Margin), kgf/cm2

Max Allowable Surf Pres (Choke Margin)

Max Allowable Surf Pres (Choke Margin), kgf/cm2 Company Min MAASP, kgf/cm2

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 20 40 60 80 100 120 140

Dep

th, m

TV

D R

T

Differential Pressure, kgf/cm2

Differential Pressure

Differential Pressure, kgf/cm2



Kick Tolerance - ExampleCalculate the kick tolerance for the following well information:

9 5/8" Casing = 14500 ftNext TD = 17000 ft

FG at 9 5/8" Casing Shoe = 16 ppgMaximum mud weight for the next hole = 14.5 ppg

Maximum formation pressure at next hole = 14 ppgGas Gradient= 0.1 psi/ft

Next hole diameter = 8 1/2 inWorkstring in the hole (from surface to TD) = 5 in

Solution:

Hmax= 2405 ft

Volume at shoe = H x Capacity between hole/drillpipe

Capacity= 0.045900525 bbl/ft

V1= 110.4 bbl, volume of bubble at the shoe

Using Boyle's Law P1V1=P2V2

V2= 107.6 bbl, volume of the bubble at the TD


The Volume for any tubular is calculated by means of the followingformula:

Where VFluid = Volume of the fluid, bblL = Length, ft

Kick Tolerance – Example (Cont’d)

The Volume for any annular is calculated by means of the followingformula:


Kick Identification

Gradient, psi/ft Gradient, sg Gradient, ppg Influx Type

0.05 - 0.2 0.115 - 0.461 0.96 - 3.85 Gas

0.2 - 0.4 0.461 - 0.923 3.85 - 7.70Probable combination of gas, oil, and/or salt water

0.4 - 0.5 0.923 - 1.153 7.70 - 9.63 Probable oil or salt water

In case of a kick occurrence the type of the influx that enters thewellbore is required to be determined.The influx gradient can be evaluated using the given ranges.

A gas kick causes higher annular pressures than a liquid kick.A gas kick has lower density than a liquid kick.A gas kick must be allowed to expand as it is pumped to surface.The objective for the well control is to always having a constantbottom hole pressure. This is only possible through having highersurface annular pressure that can be maintained through theadjustable choke.


Kick Identification (Cont’d)

Equation for the determination of the density of kick:

Where,ρkick = Kick density, ppgρmud = Mud density, ppgPCasing = Casing pressure, psiPDP = Drill pipe pressure, psiLk = Length of the kick fluid, ft


Kick Identification - ExampleA well is being drilled vertically with the following information when itbegan to flow. Following the pit gain the pump(s) are stopped, and theBOPs are closed.

TD = 12000 ftMW = 10 lbm/gal

Flow Rate = 9 bbl/minMud gain = 25 bbl

Time period during the gain = 5 min

SIDPP = 600 psiICP = 800 psi

Annular Capacity of casing = 12.9 ft/bbl

Length of DCs = 815 ft

Annular Capacity (DC) = 28.6 ft/bbl

a) Compute the density of the kick?b) Assume that the kick fluids are mixed withthe mud pumped while the was flowing. Re-calculate the density of the kick?


Kick Identification – Example (Cont’d)

SOLUTION:a) Total Capacity opposite the DCs is required to be calculated.

VDC = 31.5bbl lessMud gain = 20 bbl

If it is assumed that the kick fluids entered as a slug, then the volume of kickfluid is less than the total annular capacity opposite the drill collars.

Length of the kick fluid is calculated multiplying the mud gain with thecapacity across the DCs.

Lk=572ft

ρkick = 2.9ppg

A kick density less than about 4 ppg should indicate that the kick fluid ispredominantly gas, and a kick density greater than about 8 ppg shouldindicate that the fluid is predominantly liquid.


Kick Identification – Example (Cont’d)b)

If it is assumed that the kick fluids are mixed with mud pumped while the wellwas flowing.

Vkick mixed =45.5 bbl Vmud pump =25.5 bbl

The length of mixed zone is Lkick =1081 ft

Using the given kick density equation: ρkick = 6.04 ppg

The given density implies that the kick fluid is predominantly liquid.Since the column of the mixed zone is only 1081 ft long and under highpressure, the mean density can be related to the kick fluid density using theequation for mixtures.

ρkick = 1.5 ppg

Even though the effect of mud pump is considered the predominant kickdensity indicated that it is a gas.


AFE


AFE (Cont’d)


AFE (Cont’d)

The cost estimate sheets are usually prepared in three sections:The left column shows a code and a description for each line,The middle set of columns are used to enter time or depth-dependent rates,The right set of columns either multiplies time or depth-related costs by the relevant figure.


OFFSHORE PETROLEUM CORPORATION DRILLING & COMPLETION

WELL KAYA-2 DEPTH: MODU NAME:

SELECT DATE 22 May 2006 243 5.00 m RT TURN

REP.NO 80 Spud Date: 31/January/2006

ESTIMATED INTANGIBLE EXPENSES DATE PREVIOUS TOTAL

ACCOUNT DESCRIPTION 22 May 2006 21 May 2006

401 MOB / DEMOB RIG COST 0 0 0

402 RIG POSITIONING 0 0 0

403 DAILY RIG COSTS 72,008 78,573 5,097,348

404 FUEL / LUBE / POWER / WATER 2,543 2,680 324,896

405 BITS & MILLS 0 0 69,070

406 DAMAGE, STORM OR OPERATIONAL DELAY 0 0 574,600

407 DRILLING MUD / CHEMICALS / RELATED SERVICES 0 0 154,243

408 CONTRACT LABOUR 10,600 10,600 196,255

409 OPEN HOLE LOGGING / LWD 1,000 1,000 437,420

410 CASED HOLE LOGGING / WEIRELINE 0 0 224,560

411 DOWNHOLE COMPLETION SERVICES 0 0 203,363

412 MUD LOGGING UNIT 1,800 1,800 192,900

413 FORMATION EVALUATION 0 0 88,163

414 FISHING TOOLS / SERVICES / PIPE RECOVERY 0 0 0

415 CEMENTING JOB 0 0 42,480

416 CEMENT & PUMPING SERVICES 0 0 136,618

417 SUPPLY VESSEL 7,500 7,500 585,000

418 PERSONNEL TRANSPORT BOAT 417 417 42,900

419 DOCK, STORAGE, CRANE SERVICES 1,422 1,422 110,916

420 SHIPPING AGENT 461 461 35,958

421 EQUIPMENT RENTAL 1,000 1,000 91,940

422 CASING TUBING RUNNING TOOLS 0 200 36,890

423 HAMMER EQUIPMENT RENTALS & PERSONNEL 0 0 0

424 DIRECTIONAL DRILLING SERVICES 0 0 504,672

SUB-TOTAL INTANGIBLE 98,751 105,653 9,150,191

TANGIBLES

300 CONDUCTOR 0 0 190,190

301 CASING 0 0 528,052

302 TUBULARS 0 0 52,538

304 CHRISTMAS TREE 0 0 0

303 WELL HEAD EQUIPMENT 0 0 80,940

305 DOWN HOLE EQUIPMENT 0 0 59,452

SUB-TOTAL TANGIBLES 0 0 911,172

ADMINISTRATIVE EXPENCES

441 WELL PLANNING 984 984 76,752

442 OPERATIONS & DRILLING MANAGERS 3,497 3,497 272,766

443 PROJECT MANAGEMENT 1,628 1,628 126,984

444 SHORE BASE STAFF 695 695 54,210

445 ACCOUNTING TEAM 58 58 4,524

446 ENVIRONMENTAL PROTECTION 410 410 31,980

447 TRAVEL AND ACCOMODATIONS 1,732 1,732 135,096

448 SHORE BASE OFFICES AND RENTAL 723 723 56,394

449 COMMUNICATIONS 536 536 41,808

450 TAXES & ASSOCIATED COST 4,395 4,395 342,810

451 CUSTOM AGENT FEES 200 200 15,600

452 CUSTOM CLEARANCE & TRANSPORTATION 669 669 52,182

453 BANK CHARGES 184 184 14,352

454 RIG CREW ADMINISTRATIVE 508 508 39,624

455 INSURANCE 1,000 1,000 78,000

456 TRANSLATION AND OTHER EXPENCES 180 180 13,860

SUB-TOTAL ADMINISTRATIVE 17,399 17,399 1,356,942

TOTAL DAILY COST, USD 116,150 123,052 11,418,305

NOTE

AFE preparation requires athorough geological andgeophysical report, a costestimate for drilling andcompleting the well, and aneconomic analysis of theproposal.Preparation of well-costestimates requires research ofoffset well performance toreview the problemsencountered, the materialsused, and the effectiveness ofthe well programs (mud,cementing, casing, etc.)attempted.

AFE (Cont’d)


Bit Record

Bit records contain a wealth ofinformation essential to theDrilling Engineer.Bit records could give usefulinformation whether the bitrun was economical or not.The heading of the bit recordprovides information such asoperator, contractor, rignumber, well location,drillstring characteristics, andpump data.In addition the bit headingprovides dates for spudding,drilling our from under thesurface casing, intermediatecasing depth and reaching thehole bottom.


Bit Record (Cont’d)


Bit Run Cost Equation

whereCd = Drilling cost for bit run, USD/ftCb= Cost of bit run in hole, USDCr = Rig cost, USD/dTd = Drilling time, hTt = Trip time, hTc = Connection time, hDf = Formation interval drilled, ft

The cost of constructing a well is composed of a variety ofexpenses mainly rental costs, material and services.


Bit Run Cost Equation - Example

The lowest drilling cost is 56.3 $/ft.

Bit drilled the mostinterval is 605 ft (BIT D).The lowest drilling cost is56.3 $/ft (BIT B).The bit interval cost areranging in between13,550 – 37,150 $.The chart showing thedrilling cost comparisonfor all bits are as givenbeside.

BitBit Cost,

USDRotating Time, h

Connection Time, h

ROP, ft/hBit Run

Cost, $/ftInterval

Drilled, ftInterval Cost, $

A 1000 15 0.1 14 64.5 210 13,550

B 3000 35 0.2 13 56.3 455 25,600

C 4000 45 0.3 10 70.3 450 31,650

D 4500 55 0.3 11 61.4 605 37,150


Cementing – Single Stage


SINGLE STAGE CEMENTING

Prior to the cementing operation make sure the internal diameters of the cementing

head and outer diamaters of the plugs are measured, so that all of the plugs to be

used will be easily passing through the cementing head.

Explanation

1 Test the Cement lines up to 2000 psi.The test pressure magnitude should be up to the expected

highest pumping pressure.

2 Pump 50 bbl Spacer.

The purpose of the spacer is to condition the hole in order

fot the cement to make a good bonding. The spacer is

desired to flow in a turbulent flow state, and remain across

the open hole for a certain amount of time.

3 Drop BOTTOM PLUG; and place the top plug into the CEMENTING HEAD.It is important that during droppig the plugs the cementing

head's cap will not be opened.

4 Pump LEAD SLURRY: 101.5 bbl. Pump TAIL SLURRY: 35.3 bbl.Make sure the correct volumes are pumped. Measure

previously prepared "water volumes".

5 Drop TOP PLUG. Observe the flag for the indication to confirm the plug drop.

6 Pump 2 bbl of water in order to flush the cementing lines from cement.

Make sure enough amount of water is going to be pumped

and the cementing lines will be cleaned for future use, clear

of any cement.

7Displace cement with 290.5 bbl of drilling mud using mud pumps. The total number of

strokes are 3825. The pump output considered is: 3.19 gal/stroke.

Calculate the pump output before the cementing operation,

and make sure measure the pump volumetric efficiency is

considered in the calculations.

8

Set the plug and observe the well for a back pressure and leak. Expected plug set

pressure should be approximately: 445 psi [Excluding Frictional Pressure Losses]. Test

the plug to 945 psi for 15 MINUTES.

When getting closer to set the plug, make sure the pump

rate is reduced to minimum.

9 Wait for Cement to harden.Wait for cement based on the recommendation of the

cementing contractor. Observe the surface samples.

SEQUENCE of OPERATIONS

Cementing – Single Stage – Cont’d


Cementing – Two Stage


Cementing – Two Stage – Cont’d


Practical InformationImportant and useful practical information for the Rig Site Drilling Engineers:

Always keep it as simple as possible.Data acquisition during the course of an drilling operation is vital.The deeper the formations get, the more the abnormal pressures may increase, acasing must be set before reaching a high pressure formation.Do not believe everything you hear at the rig site, investigate and makenecessary calculations to comprehend the happening.A short trip is not a necessity every day, you do not have to do this if the hole isclean.Spend ample amount of time at the rig site to become familiar with operations.Write a procedure if you have seen it done. Report success and failures alike. Donot place blames, find solutions.Involve field personnel as part of the planning implementation operations.Bit weight will certainly effect the Penetration Rate as much as Bit Rotation will, ifhydraulics are adequate apply 5-6 klbf/in bit diameter as a general rule of thumb.For insert bits apply 2.5-3 tons/in of bit size.Softer Formations require more hydraulics than harder formations:

Apply 4-5 HHP/in2 for SOFT Formations,Apply 2-3 HHP/in2 for HARD Formations,

Insert bits do not like HIGH RPMs.Drilling record in 24 hours is by 3050 m in a 12 ¼” hole diameter drilleddirectionally by Philips Petroleum.In North Sea the formations are usually very soft.Remember Barite is a relatively inactive weighting particle.As the filtration rate decreases the penetration rate decreases as well.A shale formation would never squeeze into a wellbore.


Important and useful practical information for the Rig Site Drilling Engineers:Bit ballings are of the biggest problems associated with the PDC bits.PDC bits are usually run on performance basis, consider renting PDC bits.Tungsten carbide does not erode!Nozzles larger than 15/32 inch will have no trouble in passing LCM material.In case of getting a stuck pipe immediately PULL or SLACK OFF (Jar) to themaximum permissible magnitudes.Usually assume the following pump efficiency values:

TRIPLEX Pump 95-98% of Efficiency,DUBLEX Pump 85-90% of Efficiency.

There is almost NO frictional annular pressure loss difference up inthe annulusexcept the section of DCs.Hydraulics are not optimized but maximized. Hydraulics can be maximized usingthe HORSE POWER method or the IMPACT FORCE methods.

Hydraulic Horse Power will be maximized when 35% of the total pressurelosses of circulating system are lost at the bit.Impact Force will be maximized when 48% of the total pressure losses ofcirculating system are lost at the bit.

The following tendencies are observed for the PENETARTION RATE performance:Increasing bit weight increases penetration rate,Increasing RPM increases penetration rate,More HHP/in2 increases penetration rate,Increasing MW decreases penetration rate,Increasing solids content decreases penetration rate,Higher viscosity (especially at low shear rates) decreases penetration rate,Decreasing fluid loss decreases penetration rate.

Practical Information (Cont’d)


Practical Information (Cont’d)Important and useful practical information for the Rig Site Drilling Engineers:

It is a good sign to have the roller cone bits to have worn out by teeth to the half.Remember the diameters, generally:

Casing ≥ 4 ½”Tubing ≤ 4 ½”

8 round and BTC thread connections should be DOPED to have seal.Extremeline is an integral joint, with no coupling.The more the tension in a pipe the less the COLLAPSE occurrence.For a trip margin make sure that the MW is 0.5 ppg greater than the POREPRESSURE.For a safe drilling make sure the ECD is 0.5 ppg less than the FRACTUREPRESSURE.Most frequent failures are seen in tension design of the CASING DESIGNAPPROACH.The following Design Factors are used:

TENSION 1.6 to 2.0COLLAPSE 1.0 to 1.125BURST 1.0 to 1.25Pipe Body 1.5 to 1.8

Maximum Fracture Gradient is 1 psi/ft.0.1 psi/ft is the gas gradient.Casing joints generally have a lower Collapse value then it has a Burst value.Gate valves hold pressure both way.Temperature is important prior to cementing operation.


Practical Information (Cont’d)Important and useful practical information for the Rig Site Drilling Engineers:

Cement displacement should be at a rate of 200ft/min. The annular velocity isrequired to be maximized.Weight Indicator (MARTIN DECKER) is a relative indicator.When the weather is hot the indicator will weight more.The best surveying method in directional drilling is “Minimum Curvature Method”.The following drilling tendencies will occur with the given bed dippings:

If the bed dip < 45 deg from vertical, the bit will have a tendency to deviateup dip.If the bed dip > 65 deg from vertical, the bit will have a tendency along thebed dip or follow it.If the 45 deg < bed dip from vertical < 65 deg, the bit can do either.

In Saudi Arabia the production is mostly from the Limestone reservoirs, theformation is so strong that it does not deform even when multi-lateral wells aredrilled.In directional holes it is the DLS that causes Torque and Drag.A pendulum or slick assembly up to 1-2 degrees has got to-do the same.A pendulum assembly works at inclinations above 4-5 degrees.You obey the laws Mother Nature makes, or you pay the consequences.

Other PointsThe principal purpose of casing is to ensure the integrity of the well during drilling andproduction.Casing design evolves from completion requirements, as the completion equipmentdictates the size of the production casing or liner.Tubular strengths are selected as the well conditions dictate, and materials areselected to resist corrosion.


The success of failure of a well, from a drilling point ofviewpoint, is heavily dependent on the quality of wellplanning prior to spud.

The quality of the well planning in turn is heavily dependentof the quality and completeness of the data used inplanning.

The successful drilling engineer is a natural detective,snooping around for every snippet of useful data toanalyze and consequently implement into the well planningand ensure the implementation.

Conclusion


References

Azar J.J., Samuel G.R., “Drilling Engineering,” PennWell Publishing Company, Tulsa, OK, 2007

Bourgoyne, A., Millheim, K., and, Young, F.S.,: “Applied Drilling Engineering,” SPE Textbook, Societyof Petroleum Engineers, Richardson, TX, 1986

Carden, R.S., Grace, R.D., and, Shursen, J.L.,: “Drilling Practices,” Petroskills-OGCI, Course Notes,Tulsa, OK, 2006

“Well Control for the Rig-Site Drilling Team”, Aberdeen Drilling Schools & Well Control Training Centre,V4 Rev March, Aberdeen 2002

Mitchell R. Ed. “Petroleum Engineering Handbook – Drilling Engineering,”, Volume II The Society ofPetroleum Engineers, Richardson, TX, 2006

Johancsik C.A, Friesen D.B., Dawson R., “Torque and Drag in Directional Wells – Prediction andMeasurement,”, SPE 11380, Journal of Petroleum Technology, pp 987-992, June 1984

Devereux S., “Practical Well Planning and Drilling Manual,” PennWell Publishing Company, Tulsa, OK,1998


45

THANKS FOR YOUR

TIME

Questions?


BACK-UP SLIDES


Seven factors have been identified as the main contributors to theresultant shut in volume once a kick occurs; these are:

The formation permeability and porosity,The rate of penetration or the length of exposed formation,The hole size,The kick intensity,The method used for kick detection,The crew reaction times to alarms and the time taken to performa kick drill,The time taken to close the BOP and/or the choke.

The Factors Controlling Shut In Volumes


Force, Work, Torque and PowerThe following equations are very important for the engineering calculations:

Massis the quantity of matter in an object and is constant on earth as well as inspace.

Units of mass: kg (kilogram), 1 metric ton, 1 t = 1000 kg

ForceF=m x aForce = mass x accelerationUnit of force: N (Newton), (N = kg.m.s^-2)Practical use: daN, kN, MN

WorkEnergy is force x distance (N.m)Unit of work: J (Joule)Practical use: kJ, MJ

TorqueTorque is the tendency of a force to rotate an object about an axis.Unit: N.m (newton-metre)Practical use: klbf-ft

Poweris the work/unit-timeUnit of power: W (Watt)Practical use: kW, MW


Hole Cleaning Sketch

Laboratory work has demonstrated that drilling at an inclinationangle greater than approximately 30° from vertical posesproblems in cuttings removal that are not encountered in verticalwells.


Well Planning/Drilling Engineering

Many commercial software vendors provide a suite ofdrilling-engineering applications that enable:

casing/tubing design,torque/drag, hydraulics,hole cleaning,swab/surge,well control,cementing,drillstring-vibration/directional-performance,wellbore-stability analysis to be performed.

These engineering systems enable well planners to designthe well within concise engineering constraints.These planned models are updated during the drillingprocess to monitor the well and to ensure that designconstraints are not exceeded.


Well Control (No Expansion)

In a gas reservoir the pressure at the top of the reservoir is higher. As yougo deep the pressure decreases due to mother nature, and rules of physics.However when a tubing string in which gas is flowing considered, thepressure at the top is less as compared to pressure at the bottom.


ERD Wells


ERD Wells (Cont’d)


ERD Wells (Cont’d)


Balanced Plug Cementing


Balanced Plug Cementing (Cond’t)

PLUG CEMENT PROCEDURE

1 Conduct safety meeting ahead of pressure test of the lines.

2Fill the lines and pressure test the lines first to 500 psi 5 min, then 2500 psi 10 mins.

3Mix cement volume of 23.03 bbl of cement taking into consideration of the container's dead volume, that could not be sucked, (sample composition to be 44% water, 0.8% D-65, 0.2% Baracor).

4 Pump 20 bbl of fresh water using the cementing unit.

5 Pump 23.03 bbl of PLUG cement.

6 Pump 7.74 bbl of fresh water after the cement.

7 Displace cement with 108.21 bbl of active system mud.

8 Trip the open ended DP string slowly just above the anticipated cement top.

9Reverse circulate and observe the fluid return at the surface, fresh water should be observed.

10 Wait on cement thickening.

11 RIH with open ended tubular and tag top of the cement plug.


Bit Size, in Casing OD, in Clearance, in

36 30 3.00

26 20 3.00

17 1/2 13 3/8 2.06

12 1/4 9 5/8 1.31

8 1/2 7 0.75

6 4 1/2 0.75

Clearance Between the Bit and the Casing OD


Conventional Casing Profile

Lean-Profile

Wells drilled with different Profile Technology are concluded in considerably less daysthan conventionally drilled ones.

From an economical point of view, the following observations can be made, related toLean Profile technology:

The additional cost for the use of automatic drilling systems are nearly paid by the cost savingof less material consumed and less cost requirements for waste management.

The drilling time saving of the different Profile Technology application is the most significanteconomical issue.

Casing Profiles


Differential Sticking


Differential Sticking – Example

Example:

6.125in hole is being drilled through a100 ft depleted gas sand. The pressure in the wellbore is2000 psi greater than formation pressure of the depleted sand.

The mud cake has a thickness of 0.5 in and a coefficient of friction of0.1.

If the 4.75in collars become differentially stuck over the entire sandinterval, what force would be required to pull the collars free?

Solution:

Effective area of contact A

A = 5645 in^2

Freeing force is calculated,

Fst = 1,128,972 lbf


Differential Sticking – Cont’d

Given equations indicate that the following factors tend to increasethe sticking force:

1 High wellbore pressure caused by unnecessarily high muddensity,2 Low formation pore pressure in permeable zone (depleted oilor gas sand)3 Thick, permeable formation, which causes greater effectivearea,4 Thick mud cake, which causes a greater effective area,5 Large pipe diameter, which causes a greater effective area6 A mud cake with high coefficient of friction.

Thus,Mud having a low density, a low water loss, and a thin, slick

mud cake are best for preventing differential pressure sticking.


Cementing


Economics of drilling and cementing dictate that thesecasing points be as far apart as formation pressures andhole stability will allow.

Use of small casing severely restricts the opportunities fordeepening the well or using larger pumps.

Use of small casing to save on drilling costs is usually a poorchoice in any area in which high production rates (includingwater floods) are expected.

Cementing (Cont’d)

3 Kick

Documents

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rumalia ah

petroleum

total pressure

drilling engineer

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lin er td

greater effective