Kuliah 1bKuliah-1bKomplesi & Kerja Ulang Sumurp j g

(2 SKS)

Definisi & Konsep Dasar Komplesi & Kerja ulang Sumur

D I A d H li MMDosen : Ir. Andry Halim, MMUniversitas Trisakti - Jakarta

2012

Objective/Sasaran Konsep Dasar Komplesi Konsep Dasar Komplesi Konsep Kerja Ulangp j g

Konsep Dasar Komplesi

Well Completion atau penyelesaian sumur adalah Pekerjaan setelah pemboran, logging dan

pemasangan casing dan flanged sudah dilakukan. Komplesi dapat dilakukan dengan rig yang samaKomplesi dapat dilakukan dengan rig yang sama

atau diganti dengan snubbing unit atau unit lain yang lebih murah.

Konsep Dasar KomplesiKonsep Dasar Komplesi

Fundamentals: Why Discuss Inflow?

Completions is more than installing the equipment

It is also Designing the equipment for the life-of-the-well

Stimulating the formation to optimize well inflow

Designing the upper completion for optimum outflow

Fi di th i ht b l b t ll d ti it i t ll ti t Finding the right balance between well productivity, installation cost, operating cost and risk to optimize the well profitability.

The integration point for Reservoir, Drilling & Production

Completion Types

Open-Hole (Barefoot or Sand Control)

Single Cased-Hole Completion (perforated)

Multiple Cased-Hole Completion

Commingled Cased-Hole

Completion TypesCompletion Types

Horizontal

Dual Cased-Hole

Multi-Laterals

Commingled Monobores

Others

- Multiple tubingless

- Multi-lateralsMulti laterals

- Expandable Screens

Fundamentals: Design Process Design the ell from the reser oir o t Design the well from the reservoir out

- Well flow-rate capability- Completion sized to deliver capability

- Well drilled to contain the completion

Design for the life of the ell (e g artificial lift in late life?)- Design for the life-of-the well (e.g., artificial lift in late life?)

- Optimize completion based on NPV

Completion design is a process Completion design is a process- Plan the well (Peer Assists & Risk Assessments)

Execute the job (Action Reviews)- Execute the job (Action Reviews)

- Evaluate the results

- Document the lessons-learned (Retrospect)Document the lessons learned (Retrospect)

- Re-use the lessons to improve your next design

The Unocal Completions ProcessThe Unocal Completions Process

Determine Completion Options (Rates & NPVs)

-Identify-Validate

-Approve

(Rates & NPVs)

PLAN

-Approve

EXECUTEDOCUMENTKnowledge E i t

Completion OpportunitiesCFT

EXECUTEDOCUMENTCapture Best Practices/ Lessons Learned

Capture Best Practices/ Lessons Learned

Maintain Performance Accountability

Maintain Performance Accountability

Environment

EVALUATE Completed Wells Ops.

Analyze TrendsAnalyze Trends

The Unocal Completions ProcessThe Unocal Completions Process

Get InformationAudit

Risk Manageme

Risk Identification

Post Project Review

ManagementProgram

Risk Assessment

Project Execution &Daily risk mitigation

Risk Mitigation

Communication

Fundamentals: Design Issues Key Design Issues:

Well Inflow / OutflowWell Inflow / Outflow Completion Selection NPV Optimization (economics) Design and Modelingg g

- Pre-Job Nodal Modeling (Prosper)- Tubular Stress Analyses (TDAS or WellCat)- Torque-and-Drag (Compass)

F S i l i (S i Pl )- Fracture Stimulation (StimPlan)- Erosion Calculations (Flux-rates)- Materials Selection (Metals, elastomers)- Formation Geology / Fluids and Filtrationgy

Execution / Pumping -Design and QC (operations, costs, etc)

Post-Job Evaluation Production

Kerja Ulang SumurKerja Ulang Sumur

Kerja Ulang Sumurj g

Materi terkaitMateri terkait komplesi sumurp

PERFORATING

OPTIMIZING FLUID FLOW

Casing

Cement

Damaged Zone(Permeability kd)

Undisturbed Formation(Permeability ku)

Goal : to establish effective (Permeability kd)

Crushed Zone(Permeability kc)

communication between the wellbore and the reservoir

Factors that influence fluid flow through the perforations :Factors that influence fluid flow through the perforations :- Perforating Geometry- Damaged zones around the wellbore- Crushed zones around the perforation

Diff ti l th t i t h f ti- Differential pressure that exist when perforating

PERFORATING GEOMETRY

Perforating geometry involves : Gun Phasing Shot density Perforation diameter Penetration depth

Perforation Diameter

PenetrationGun Phasing0.1 ent. hole PenetrationGun Phasing2.5 penetration

Cement

7 Casing7 Casing

Bore hole0.3 ent. hole6.0 penetration

FORMATION FRACTURING

OBJECTIVES

The objective of hydraulic fracturing for well stimulation is to increase well productivity by creating a highly conductive path (compare to reservoir permeability) some distance away from wellbore into the p y) yformation.

Fracture InitiationA hydraulic fracture treatment is accomplished by pumping a suitable fluid into the formation at a rate faster than the fluid can leak off into the rock. Fluid pressure is built up sufficient to overcome the earth compressive stress holding the rock material together. The rock thencompressive stress holding the rock material together. The rock then parts or fractures along a plane perpendicular to the minimum compressive stress in the formation matrix.

Fracture ExtensionAs injection of frac fluid continues, the fracture tends to grow in width

fl id i th f t t d th f t f kas fluid pressure in the fracture, exerted on the fracture face, works against the elasticity of the rock material. After sufficient frac fluid pad has been injected to open the fracture wide enough to accept proppant, sand is added to the frac fluid and is carried into the fracture p pp ,to hold it open after the job.

The growth upward or downward may be stopped by a barrier formation; downward growth may also be stopped by fallout of sand to ; g y pp ythe bottom of the fracture. The growth outward away from the wellbore will be stopped when the rate of frac fluid leakoff through the face of the fracture into the formation equals the rate of fluid injection into the fracture at the wellborefracture at the wellbore.

Mechanics of Fracturing vRegional Rock Stresses

h2v = Total vertical stress, psih1

Total vertical stress, psi= 0.007 D= average rock density, lb/ft= depth, ft

D

= 0.007 D Pr= formation pore pressure, psiPr

v h1 = Maximum principal horizontal matrix stressh2 = Maximum principal horizontal matrix stress

Horizontal Matrix stress depend on rock properties and pore pressure.

ZONE ISOLATION SQUEEZE CEMENTINGPACKERS

Squeeze Cementing - DefinitionSqueeze Cementing Definition

Injection of Cement Slurryinto the voids behind theinto the voids behind thecasing

Dehydration of cementyrequires: fluid fluid-loss, porous(permeable) matrix,differential pressure, time.

Injection below or abovefracture pressure

PACKERS

Objectives

All k ill tt i f th f ll i bj ti h thAll packers will attain one or more of the following objectives when they are functioning properly :

1. Isolate well fluids and pressure.p

2. Keep gas mixed with liquids, by using gas energy for natural flow.

3 Separate producing zones preventing fluid and pressure contamination3. Separate producing zones, preventing fluid and pressure contamination.

4. Aid in forming the annular volume (casing/tubing/packer) required for gas lift or subsurface hydraulic pumping systems.

5. Limit well control to the tubing at the surface, for safety purposes.

6 Hold well servicing fluids (kill fluids packer fluids) in casing annulus6. Hold well servicing fluids (kill fluids, packer fluids) in casing annulus.

COMPLETION FLUID

FungsiFungsi C/WO FluidsC/WO Fluids

Fungsi utama: Stabilize the wellbore & control sub-

surface pressurepFungsi lain: Suspend equipments and transport solids Suspend equipments and transport solids Sebagai medium untuk well logging Pelumasan Displace other fluidsp

JENIS FLUIDA C/WOJENIS FLUIDA C/WOJENIS FLUIDA C/WOJENIS FLUIDA C/WO

SolidsSolids Free Brine Systems (Clear Fluid)Free Brine Systems (Clear Fluid) SolidsSolids--Free Brine Systems (Clear Fluid)Free Brine Systems (Clear Fluid)

SolidsSolids Laden FluidsLaden Fluids SolidsSolids--Laden Fluids Laden Fluids Drilling FluidsDrilling Fluids Lease Water or SeawaterLease Water or Seawater Lease Water or SeawaterLease Water or Seawater

SolidsSolids--Free Brine SystemsFree Brine Systemsyy

NaCl dan KCl brines biasanya dibuat ydengan melarutkan kristal garam kering dengan air karena densitas maximum

d d l f d h b lyang dapat dicapai relatif rendah; bila dijual dalam bentuk larutan biaya angkutan menjadi mahal karena adanyaangkutan menjadi mahal karena adanya tambahan berat air.

NaBr biasanya dibuat dari garam kering NaBr biasanya dibuat dari garam kering atau tersedia dari supplier dalam bentuk larutan pekat dengan densitasbentuk larutan pekat dengan densitas sesuai dengan kebutuhan.

FORMATION DAMAGE

DamageDamage Zone

Basic Causes of DamageC i h f i fl id i h b i f F i DContact with a foreign fluid is the basic cause of Formation Damage. This foreign fluid may be a drilling mud, a clean completion or workover fluid, a stimulation or well treating fluid, or even the reservoir fluid itself if the original characteristics are alteredreservoir fluid itself if the original characteristics are altered.Most oilfield fluids consist of two phases liquid and solids. Either can cause significant formation damage through one of several possible mechanismspossible mechanisms.

Plugging Associated with SolidsOccurs on the formation face, in the perforation, or in the formation :Weighting materials, clays, viscosity builder, fluid loss control material, lost circulation materials, drilled solid, cement particles, perforating charge debris rust and mill scale pipe dope precipitated scale etcdebris, rust and mill scale, pipe dope, precipitated scale, etc.

Large Solids (perforating tunnel, face of an open hole zone, face of natural or created fracture or in fracture channel) Small Solids (may be carried for some distance into the pores) Solids Precipitated (scale or asphaltene/paraffin)

Plugging Associated with Fluid Filtrategg gThe liquid filtrate may be water containing varying types and concentrations of positive and negative ions and surfactants. It may be a hydrocarbon carrying various surfactants. The liquid is forced into porous zones by differential pressure, displacing orThe liquid is forced into porous zones by differential pressure, displacing or commingling with a portion of the virgin reservoir fluids. This may create blockage due to one or more of several mechanism that may reduce the absolute permeability of the pore, or restrict flow due to relative permeability or viscosity

ff teffects.

Classification Of DamageTh h i th t lt i f ti d b llThe numerous mechanisms that result in formation damage may be generally classified as to the manner by which they decrease production : Reduced absolute permeability of formation results from plugging of pore channels by induced or inherent particles.y p Reduced relative permeability to oil resultss from an increase in water saturation or oil-wetting of the rock. Increase viscosity of reservoir fluid results from emulsions or high-viscosity treating fluidsviscosity treating fluids.

100 kd = 50 md Relates productivity loss to degree and depth of damage The important

1

10

c

t

i

o

n

R

a

t

e

b

b

l

/

d

a

y

Permeability of undamaged reservoir = 100 md

kd = 1 md

kd = 10 md and depth of damage. The important point is that with radial flow, the critical area is the first few feet away from the well bore.

0.01

0.1

0 5 10 15 20 25

P

r

o

d

u

c

y g

Formastion thickness 10 ftWell bore radius 0.25 ftDrainage Radius 500 ftOil Visosity 0.5 cpDrawdown 53.6 psi

0 5 10 15 20 25

Radius of damaged zone beyond well bore, ft

Cement

7 CasingBore hole

Mengapa komplesiMengapa komplesi sumur penting ?p g

Fundamentals: Why Discuss Inflow?Fundamentals: Why Discuss Inflow?

60%

Andrew

First Year productionabove expectation

Ram Powell

0

20%

Arkwright OverspendUnderspend

Ram Powell

-20%

- 40% 40% 80%

ETAP

LiuhuaChirag

Cusiana ph 2 Harding HugotonW. Seno

-60% Schiehallion

Pedernales

CupiaguaHugoton

-100%Foinaven

Pedernales First Year production

below expectation

Hi t i ll th i d t h t b t t di ti t d ti itHistorically, the industry has not been great at predicting cost, productivity or risk. We must do better to handle Deepwater projects

Completion Options Completion Options LifeLife--ofof--Well IssuesWell IssuesClassic Failure Rate

40

45

50Completions are not much different from other commodities (e.g., cars)

20

25

30

35

40

#

F

a

i

l

u

r

e

s

S d C l F il B A d C l i

0

5

10

15

0.1 1 10 100

Time

Sand Control Failure By Age and Completion Type

7080

a

i

l

SOC Time

3040506070

P

W

e

l

l

s

T

h

a

t

F

a SOCCHGPOHGPFP FPs cost more but last

longer

01020

0 5 10 15 20

%

o

f

G

P longer

Screen-only cost less but fail more frequently

Years on ProductionRef G. King Completion Database dated 2004.

Questions ?

PR-1

1. Apa yang dimaksud dengan komplesi2. Sebutkan jenis jenis komplesij j p3. Apa yang dimaksud dengan kerja ulang4 Sebutkan key issues pada komplesi4. Sebutkan key issues pada komplesi

sumur