[ABSTRAK
Interpretasi merupakan proses yang penting dalam penentuan posisi dangeometri reservoar. Akan tetapi proses interpretasi dalam PSTM masih memilikiketerbatasan imaging dan mengakibatkan kesalahan dalam interpretasi. Terlebih untuklapangan yang memiliki variasi kecepatan secara lateral. Variasi kecepatan secara lateralakan mengakibatkan pembelokan sinar gelombang yang mengakibatkan perekamangelombang tidak hiperbola.Pencitraan bawah permukaan ketika terd apat adanya variasi kecepatan lateralyang besar sehingga menyebabkan terjadinya pembelokan sinar pada batas lapisan,nonhyperbolic moveout, dan struktur lapisan yang kompleks harus dilakukan denganprestack depth migration (PSDM). PSDM merupakan teknik migrasi sebelum stackingdalam kawasan kedalaman. Dibandingkan PSTM, PSDM lebih memperhatikan traveltime.Untuk melakukan PSDM dibutuhkan geometri reflektor dan model kecepataninterval yang mendekati model bumi sebenarnya. Model kecepatan interval yangdigunakan masih diasumsikan isotropi sehingga hasil seismik yang dihasilkan belumakurat secara posisi ataupun image. Oleh karena itu dibutuhkan parameter anisotropiuntuk memperbaiki masalah tersebut.Jenis anisotropi yang akan digunakan adalah Vertical Transverse Isotropy(VTI)dimana sumbu simetri anisotopi berarah verikal. Parameter anisotopi yang digunakanadalah ε dan δ. Delta (δ) adalah parameter anisotropi gelombang P pada near verticalsedangkan epsilon merupakan parameter anisotropi gelombang P pada near horizontal.Secara praktis, delta (δ) berhubungan dengan level posisi reflekktor sedangkan epsilonlebih berhubungan dengan koreksi far offset yaitu efek hockeystickDengan melakukan PSDM anisotropi, pemodelan secara vertical dan horizontalakan lebih akurat sehingga diharapkan dapat mengurangi kesalahan dalam interpretasi.
ABSTRACT
Seismic interpretation is a crusial step in reservoar position and geometridetermining. But then interpretation process in PSTM data which has limited on imagingwill appear interpretation pitfalls. Moreover for field wich has strong lateral velocityvariation. Strong lateral velocity variation will bend the ray which will createunhiperbolic moveout.Imaging subsurface in existence with strong lateral velocity variation causes raybending at layer boundary, non-hyperbolic moveout, and complex overburden structuresneeds prestack depth migration (PSDM). PSDM is before stacking migration technique indepth domain. As compared to PSTM, PSDM more does honour to travel time.PSDM needs reflector geometry and interval velocity model which resemble to thesub surface model. The interval velocity model which is used still assumes isotropycondition. It makes imaging is not precise both in position and imaging. Therefore,anisotrophy media assuming is required to solve those issues.Vertical Tranverse Isotropy (VTI) is anisptrophicallly medium approximation withvertical symmetry axis. ε and δ are anisotropic Thomsen parameter which will beapplied in this research. Delta (δ) is near vertical P wave anisotropy parameter whereasepsilon (ε) is near horizontal P wave anisotropy parameter. Practically, delta (δ) relatedwith reflector position (well seismic tie) whereas epsilon related with far offset correctioncalled hockeystick effect.Application of anisotropic PSDM with the real data shows significant improvementin lateral and vertical positioning that approaches true model, if compare to isotropicPSDM. The image itself is better than the isotropic PSDM that shows strong and continuereflectors amplitudes;Seismic interpretation is a crusial step in reservoar position and geometridetermining. But then interpretation process in PSTM data which has limited on imagingwill appear interpretation pitfalls. Moreover for field wich has strong lateral velocityvariation. Strong lateral velocity variation will bend the ray which will createunhiperbolic moveout.Imaging subsurface in existence with strong lateral velocity variation causes raybending at layer boundary, non-hyperbolic moveout, and complex overburden structuresneeds prestack depth migration (PSDM). PSDM is before stacking migration technique indepth domain. As compared to PSTM, PSDM more does honour to travel time.PSDM needs reflector geometry and interval velocity model which resemble to thesub surface model. The interval velocity model which is used still assumes isotropycondition. It makes imaging is not precise both in position and imaging. Therefore,anisotrophy media assuming is required to solve those issues.Vertical Tranverse Isotropy (VTI) is anisptrophicallly medium approximation withvertical symmetry axis. ε and δ are anisotropic Thomsen parameter which will beapplied in this research. Delta (δ) is near vertical P wave anisotropy parameter whereasepsilon (ε) is near horizontal P wave anisotropy parameter. Practically, delta (δ) relatedwith reflector position (well seismic tie) whereas epsilon related with far offset correctioncalled hockeystick effect.Application of anisotropic PSDM with the real data shows significant improvementin lateral and vertical positioning that approaches true model, if compare to isotropicPSDM. The image itself is better than the isotropic PSDM that shows strong and continuereflectors amplitudes, Seismic interpretation is a crusial step in reservoar position and geometridetermining. But then interpretation process in PSTM data which has limited on imagingwill appear interpretation pitfalls. Moreover for field wich has strong lateral velocityvariation. Strong lateral velocity variation will bend the ray which will createunhiperbolic moveout.Imaging subsurface in existence with strong lateral velocity variation causes raybending at layer boundary, non-hyperbolic moveout, and complex overburden structuresneeds prestack depth migration (PSDM). PSDM is before stacking migration technique indepth domain. As compared to PSTM, PSDM more does honour to travel time.PSDM needs reflector geometry and interval velocity model which resemble to thesub surface model. The interval velocity model which is used still assumes isotropycondition. It makes imaging is not precise both in position and imaging. Therefore,anisotrophy media assuming is required to solve those issues.Vertical Tranverse Isotropy (VTI) is anisptrophicallly medium approximation withvertical symmetry axis. ε and δ are anisotropic Thomsen parameter which will beapplied in this research. Delta (δ) is near vertical P wave anisotropy parameter whereasepsilon (ε) is near horizontal P wave anisotropy parameter. Practically, delta (δ) relatedwith reflector position (well seismic tie) whereas epsilon related with far offset correctioncalled hockeystick effect.Application of anisotropic PSDM with the real data shows significant improvementin lateral and vertical positioning that approaches true model, if compare to isotropicPSDM. The image itself is better than the isotropic PSDM that shows strong and continuereflectors amplitudes] |
T42247-Ginanjar Satria Putra.pdf :: Unduh