Study Kasus
Diketahui Kedalaman sumur : 2531 ft Panjang casing 7” : 252864 ft Panjang casing 9 5/8” :398 ft Diameter lubang sumur 8,5” caliper 9,526”
Diameter dalam casing 7 “ : 6,184 “ Diameter dalam casing 9 5/8 : 8,835 “ Panjang pocket : 2,36 Top tail: 1500 ft L st : 91,53 ft Penyelesaian 1.
Menentukan volume dan capasitas cement slurry
Penentuan volume open hole 8,5”
VOH
(hole diameter ) 2
VOH
9,326 2
1029 ,4
0,0845 bbls/ft atau 0,4744 cuft/f t
Penentuan volume casing 7”
VCsg 7"
VCsg 7"
1029 ,4
(inside diameter csg cs g 7" ) 2
1029 ,4 6,184 2
1029 ,4
0,0371 bbls/ft atau 0,2086 cuft/ft
Penentuan volume annulus casing dengan casing VANN
VANN
(hole diameter) 2
(outside diameter csg)2
1029,4 (8,835
2
1029,4
7) 2
0,0282 bbls/ft atau 0,1585 cuft/ft
Penentuan anulus OH dengan casing 7”
VANN
VANN
2.
(hole diameter) 2
1029,4 (9,326
(outside diameter csg)2
2
7) 2
1029,4
0,0369 bbls/ft atau 0,2071 cuft/ft
Perhitungan Cement slurry yang dibutuhkan a.
Tail slurry
Perhitungan Rate Hole atau volume Pocket yang diperlukan Vpocket = Panjang Pocket x Capacity Vpocket = 2.36 ft x 0.0845 bpf Vpocket = 0.199 bbl Untuk mencegah terjadinya kekurangan pada volume pocket maka diberikan safety factor (excess) sebesar 50%. Vpocket =0.199 bbl x 50% = 0.1 bbl
Perhitungan volume Shoetrack yang diperlukan Vst = Panjang Shoetrack x Capacity Vst = 91.33 ft x 0.0371 bpf Vst = 3.393 bbl
Perhitungan kebutuhan cement slurry antara casing 7” dan diameter lubang 8,5” Calp 9,326” .
VAnn = (L casing 7” – L top tail ) x capacity VAnn = (2528.64 – 1500) x 0,0369 bpf VAnn = 37,95 bbl Untuk mencegah terjadinya kekurangan pada volume annulus maka diberikan safety factor (excess) sebesar 50%. VAnn = 37,95 bbl x 50% = 18,97 bbl
b.
Lead Slurry
Perhitungan kebutuhan cement slurry antara casing 7” dan diameter lubang 8,5” Calp 9,326”.
VAnn = (L top tail – L csg 95/8 ) x capacity VAnn = (1500 – 398) x 0,0369 bpf VAnn = 40.65 bbl Untuk mencegah terjadinya kekurangan pada volume annulus maka diberikan safety factor (excess) sebesar 50%. VAnn = 40,65 bbl x 50% = 20,33 bbl
Perhitungan kebutuhan cement slurry antara casing 7” dan casing 95/8”
VAnn = L csg 95/8 x capacity VAnn = 398 ft x 0,0282 bpf VAnn = 11,23 bbl
Total Volume Tail = 0.199 bbl + 0.1 bbl + 3.393 bbl + 37,95 bbl + 18,9 bbl = 60,61 bbl atau 340,3 cuft Total Volume Lead = 40.65 bbl + 20,33 bbl + 11,23 bbl = 72,21 bbl atau 405,4 cuft
3.
Sack of Cement Required a.
Lead Slurry Densitas
: 12.5 ppg
M/W
: 12,612 gal/sack
Yield
: 2,156 ft2/sack
Perhitungan jumlah semen per sack yang dibutuhkan dalam penyemenan lead slurry Slurry Volume
Sack Of Cement
Sack Of Cement
Yield Slurry
405,4 cuft
Water
2,156 cuft/sack
188,1 sack
= Sack of cement × water required = 188,1 sack × 12,612 GPS = 2372,31 gallon (56,5 bbl )
Total mixing water = 56,5 bbl + Excess 5 bbl = 61 bbl
b.
Sack of Cement x Total M/W
TotalSemen Yang Dibutuhkan
Total Semen Yang Dibutuhkan
M/W 188,1 sack x 61 bbl 56,6 bbl
204,7 sack
Tail Slurry Densitas
: 15.8 ppg
M/W
: 5,310 gal/sack
Yield
: 1,183 ft2/sack
Perhitungan jumlah semen per sack yang dibutuhkan dalam penyemenan Tail slurry Slurry Volume
Sack Of Cement
Sack Of Cement
Water
Yield Slurry 340,3 cuft
1,183 cuft/sack
287 ,58 sack
= Sack of cement × water required = 287,58 sack × 5,310 GPS = 1527,05 gallon (36,4 bbl )
Total mixing water = 36,4 bbl + Excess 5 bbl = 41 bbl
4.
Sack of Cement x Total M/W
TotalSemen Yang Dibutuhkan
Total Semen Yang Dibutuhkan
M/W 287,58 sack x 41 bbl 36,4 bbl
Slurry compositions a.
Lead slurry F/W
= concentration × BWOC = 10,464 GPS × 204,7 : 42 = 51,01 bbls
PC-X61L
= concentration × sack of cement = 0,068 GPS × 204,7 = 13,84 gal
PC-G71L
= concentration × sack of cement = 1,325 GPS × 204,7 = 271,30 gal
PC-P50S
= concentration × sack of cement = 2%× 204,7 x 94 = 384,90 bbls
PC-GS2L
= concentration × sack of cement = 0,663 × 204,7 = 135,65 bbls
327 ,1sack
PC-H21L
= concentration × sack of cement = 0,007 × 204,7 = 1,52 bbls
b.
Tail Slurry F/W
= concentration × BWOC = 0,663 × 327,1 : 42 = 135,65 bbls
PC-X61L
= concentration × sack of cement = 0,034 × 327,1 = 11,05 gal
PC-G71L
= concentration × sack of cement = 0,883 × 327,1 = 289,00 gal
PC-H21L
= concentration × sack of cement = 0,021 × 327,1 = 6,95 gal
PC-GS2L
= concentration × sack of cement = 0,663 × 327,1 = 216,75 gal
PC-F41L
= concentration × sack of cement = 0,096 × 327,1 = 31,49 gal
Chemical wash flusher and spacer Weigthted spacer volume : 50 bbl (for bbl spacer = 35 gal drill water + 0,283 gal PC-X61L + 0,525 gal PCS21L + 17,67 Lbs PC-S21S + 1,05 gal PC-W10L + Barite )
Estimate cost Casing Additive
Accessory
Unit Total
Unit
Price
Price
PC-X61L
24,89
gal
$ 25,00
$ 622,27
PC-G71L
560,30
gal
$ 39,00
$ 21.851,76
PC-P50S
384,90
gal
$2,30
$ 885,27
PC-GS2L
352,4
gal
$ 25,00
$ 8.810,00
PS-H21L
8,48
gal
$ 28,60
$ 242,39
PC-F41L
31,49
gal
$ 21,00
$ 661,36
Spacer
2100,00 gal
$ 2,60
$ 5.460,00
$ 7" Float Shoe
1
ea
1.000,00
$ 1.000,00
$ 7" Float Collar
1
ea
1.800,00
$ 1.800,00
7" Top Plug
1
ea
$ 420,00
$ 420,00
7" Bottom Plug
1
ea
$ 420,00
$ 420,00
Centralizer
9
ea
$ 56,00
$ 504,00
7" Stop Collar
2
ea
$ 18,00
$ 36,00
7"
Bow
