Transcript Coastal and Marine Resources Management

TEKNOLOGI
PEMROSESAN HIDROKARBON
K05
PEKERJAAN PEMBORAN-02
(drilling rig, drilling mud, casing, completion,
production, abandonment)
Dr. Wahyudi
Dept. Ocean Engineering, ITS
Surabaya
3. CASING
• Pemboran HC di daerah yg relatif belum diketahui karakteristik
geologinya sangat perlu adanya casing
• Fungsi casing:
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Mengontrol tekanan sumur
Wellbore caving prevention
Freshwater sand isolation
Memperlancar instalasi production tubing
• Secara umum
– ½ sampai 1/3 jarak tersisa sampai target depth selanjutnya perlu casing
• Kasus tertentu:
– Lost circulation
– Overpressured formation
– Caving shale
• Tekanan formasi
3. CASING
• Tekanan Formasi:
– Tekanan yg diberikan oleh fluida mengisi rongga formasi, bisa gas, oil or water.
– Bukan tekanan beban total yg dialami butiran2 batuan
– Secara prinsip tekanan formasi harus < atau = tekanan beban total, jika tidak tekanan
formasi akan memecahkan formasi di atasnya dan fluida akan keluar untuk membebaskan
tekanan yg berlebihan MV
• Tekanan Formasi dibentuk oleh:
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•
•
•
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Gradien hidrostatik (0.45 – 0.46 psi/ft)
Gradien hidrodinamik (komponen lateral perbedaan kolom air )
Gradien geostatik (tekanan beban total krn material di atasnya)
Gradien geodinamik (disebabkan oleh gaya tektonik)
Tekanan Formasi Abnormal:
– Tekanan formasi > yg diperhitungkan dari gradien hidrostatik
– Disebabkan karena pengendapan yg sangat cepat sehingga air dalam lempung/sedimen
tdk dapat keluar saat kompaksi.
– Air tetap dalam sedimen (fine grain) shg seolah-olah butiran antar batuan mengapung
dalam air
– Tekanan geostatik sebagian besar didukung oleh air formasi  tekanan formasi abnormal
– Sering terjadi pd sedimentary basin dimana kompaksi tdk dpt berjalan baik, berasosiasi dg
mud diapir & mv.
– Di Indonesia dijumpai di cekungan Sumatra Utara & Madura. Di AS dijumpai tekanan
formasi mencapai 26000 psi pd kedalaman 20000 ft (Kusumadinata, 1980)
3. CASING
“d-exponent”
Untuk mendeteksi tekanan formasi dilakukan dengan
menghitung “de eksponen”. Penurunan nilai d-exponent
menunjukkan adanya tekanan tinggi yg tdk normal:
D=
R
N
W
D
log (R/60N)
log (12 W/106D)
: kecepatan penetrasi (ft/hr)
: kecepatan putaran (rpm)
: berat pada bit (lb)
: diameter lubang bor (inchi)
3. CASING
3. CASING
Drilling Operations - Making Holes
Conductor
Surface
casing
Intermediate
casing
Production
casing
Production
liner
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
Depth reference
below derrick floor - bdf
roller kelly bushing - rkb
Main deck
Cellar deck
depth reference
Sea level
Conductor
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
Main deck
Cellar deck
Sea level
Conductor
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
• Drill production holes
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
• Drill production holes
• Run and set production casing
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
• Drill production holes
• Run and set production casing
• Cement casing
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
• Drill production holes
• Run and set production casing
• Cement casing
• Drill production holes
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
• Drill production holes
• Run and set production casing
• Cement casing
• Drill production holes
• Run and set liner
Drilling Operations - Making Holes
Typical Sequence of Operations :
• Rig up
• Drill surface holes
• Run and set surface casing
• Cement casing
• Drill intermediate holes
• Run and set intermediate casing
• Cement casing
• Drill production holes
• Run and set production casing
• Cement casing
• Drill production holes
• Run and set liner
• Cement liner
Casing Schemes
There are various casing
schemes depending on
drilling, completion and
reservoir considerations e.g.
Hole Size
Casing Size
Pile
26” conductor
20 1/4”
18 5/8”
17 1/2”
13 3/8”
12 1/4”
9 5/8”
8 1/2”
7”
What is well completion ?
What is the objective of well completion ?
What is the objective of well completion ?
• To provide communication between
reservoir and the surface
• With subsurface and surface flow
control mechanisms
Why well completion is so important ?

To effectively drain out the reservoir
increase productivity and recovery

To provide subsurface and surface flow control

Increase asset value through cost optimisation - well
completion cost represents one of the major contributor to total
wells expenditure in field development
fluids to the surface -
Well Completion Communicate Reservoir
to Surface
reservoir
reservoir
reservoir
reservoir
Well Completion Communicate Reservoir to Surface
Typical Sequence of Operations :
• Well clean out
reservoir
reservoir
Clean Out
Assembly
Bit and
Scraper
+
Cleanout
Fluid
reservoir
reservoir
Well Completion Communicate Reservoir to Surface
Perforating
gun
Assembly
Typical Sequence of Operations :
• Well cleanout
• Perforate
• Kill well
• (Sand exclusion - if required)
reservoir
reservoir
reservoir
reservoir
Well Completion Communicate Reservoir to Surface
Typical Sequence of Operations :
• Well cleanout
• Perforate
• Kill well
• (Sand exclusion - if required)
• Run and set completion string
reservoir
reservoir
reservoir
reservoir
Well Completion Communicate Reservoir to Surface
Typical Sequence of Operations :
• Well cleanout
• Perforate
• Kill well
• (Sand exclusion - if required)
• Run and set completion string
• Install X-mas tree
Depth reference - THF
well
Well Completion Communicate Reservoir to Surface
Typical Sequence of Operations :
• Well cleanout
• Perforate
• Kill well
• (Sand exclusion - if required)
• Run and set completion string
• Install X-mas tree
• Tie-in well
To
Production
system
well
Production
header
Well Completion Communicate Reservoir to Surface
Typical Sequence of Operations :
• Well cleanout
• Perforate
• Kill well
• (Sand exclusion - if required)
• Run and set completion string
• Install X-mas tree
reservoir
• Tie-in well
• Unload and produce well
• Handover to production
reservoir
reservoir
reservoir
Typical Well
Completion
Completion Tubing Sizes
Tubing size ranges from 2 3/8”
2 7/8”
3 1/2”
4”
4 1/2”
5 1/2”
7”
To as large as 9 5/8”
What can happen if completion not
optimal ?

Low rate due to restriction
 in the reservoir - near wellbore (skin)
 in the completion tubing
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Early water or gas breakthrough
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Faster production decline
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Equipment failure e.g. surface choke cut
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Frequent shutdown e.g. sand in separator
COST
REVENUE
Something we can observe at surface and
feel at surface
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temperature
pressure
physical damage
sound
vibration
etc
Various Forms of of Wellbore Sketches
X
V
S
V
5. PRODUCTION
6. ABANDONMENT