Datum Corection
7
1 PENGOLAHAN DATA SEISMIK By : Ardian Novianto
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Transcript of Datum Corection
1
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
1. Koreksi efek near-surface (weathering layer/inconsisten layer)
2. Penggantian inconsistance layer
3. Memodelkan kembali lapisan near surface
Tahapan yang harus dilakukan dalam koreksi Datum :
Near-Surfacemodel
Datum
2
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
Near-Surfacemodel
Sub-modelLayer
Base Horizon
STRIPPING:
TG= - U + TS
ELVS - D - ELVB
VNSTS = - and
Where VNS = kecepatan rata-rata dari bottom lubang ke base horizonU = pengukuran uphole timeD = kedalaman shot
3
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
Where VNS = kecepatan rata-rata dari bottom lubang ke base horizonU = pengukuran uphole timeD = kedalaman shot
ELVDAT - ELVB
VRTR = + * 2REPLACEMENT:
T = TS+ TG+ TRTOTAL sifting :
Where VR = Kecepatan pengganti(replacement velocity)
Quis
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?4
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
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A 135’B 110’
C 95’D 65’
E 20’
0.0240.030
0.0360.022
0.014LVL
Surface Elevation
72’70’ 80’
65’60’ shot Depth
LVL
DATUMSEA LEVEL
5
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
LOCATION UHT SHOT TODATUM TIME
SURFACE TODATUM TIME
A 0.024 0.008 Sec 0.032 Sec
B 0.030 0.005 Sec 0.035 Sec
C 0.036
D 0.022
E 0.014
Shot Location Geophonelocation
Static Corrections
B A - (0.005 + 0.032) = - 0.037
C A - (0.002 + 0.032) = ?
D B
E C
E D
1. Perhitungan Shot to datum Time :
Shot to Datum Time = Elevation – Shot depthDatum Velocity
Diketahui besarnya Datum Velocity = 8000’/sec.- Titik A : Shot To Datum time = 135 – 72
8000= 0.0079 Sec
- Titik B : Shot To Datum time = 110 – 708000
= 0.005 Sec
6
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
Diketahui besarnya Datum Velocity = 8000’/sec.- Titik A : Shot To Datum time = 135 – 72
8000= 0.0079 Sec
- Titik B : Shot To Datum time = 110 – 708000
= 0.005 Sec
2. Perhitungan Surface to datum Time :
Surface to datum Time = UHT + Shot to Datum Time
- Titik A : 0.024 + 0.008 = 0.032 Sec- Titik B : 0.030 + 0.005 = 0.035 Sec
3. Perhitungan Static Corecctions
Static Correction = - (Shot to Datum Time + Surface to Datum Time)
Tanda Minus disini merupakan koreksi terhadap posisi datumnya denganasumsi bahwa terdapat kelebihan waktu diatas posisi datum sehingga harusdikurangkan.
- Shot Location B dan Geophone Location A= - (Shot to Datum Time B + Surface to Datum Time A)= - (0.005 + 0.032)= - 0.037 Sec
- Shot Location C dan Geophone Location A= - (Shot to Datum Time C + Surface to Datum Time A)= ??
7
PENGOLAHAN DATA SEISMIK
By : Ardian Novianto
Tanda Minus disini merupakan koreksi terhadap posisi datumnya denganasumsi bahwa terdapat kelebihan waktu diatas posisi datum sehingga harusdikurangkan.
- Shot Location B dan Geophone Location A= - (Shot to Datum Time B + Surface to Datum Time A)= - (0.005 + 0.032)= - 0.037 Sec
- Shot Location C dan Geophone Location A= - (Shot to Datum Time C + Surface to Datum Time A)= ??
