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Metode Seismik Dalam Usaha Pendeteksian Reservoir Minyak Dan Gas Bumi (Penerapan Metode AVO) Awali Priyono
Jurnal Matematika & Sains Vol 5, No 1 (2000)
Publisher : Institut Teknologi Bandung

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In this paper, a study of AVO (Amplitude Versus Off-Set) technique as hydrocarbon detection will be presented. The study have been carried out in the carbonate and sandstone reservoirs. AVO analysis, as showed in the range limited off set, indicates that dry carbonate, water or gas in the carbonate reservoir can be recognized from their amplitude responses. The difference in Poissons ratio value between water and gas in the carbonate reservoir is relative small, therefore care must be taken in the analysis. The study shows that, in the case of sandstone reservoar, the AVO response does not depend on the gas saturation, but this is not the case for oil saturation. AVO inversion using Damp Approximation Inverse (DAI) gives good accuracy, therefore this method is very helpful in estimating the elastic parameters such as Poissons ratio and modulus Young in relation to reservoir characterization.

Perbandingan Hasil Atenuasi Tomografi 3D Menggunakan Metoda Spectral Fitting & Spectral Ratio Dalam Usaha Pemetaan Bawah Permukaan (Studi Kasus Gunung Guntur) Awali Priyono; Gede Suantika; Sri Widiyantoro
Jurnal Matematika & Sains Vol 15, No 3 (2010)
Publisher : Institut Teknologi Bandung

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Spectral fitting and spectral ratio methods are tested to estimate the Q value or attenuation in the effort on imaging the subsurface structure using three-dimensional tomographic inversion techniques. In this study, we used microearthquakes data around Mount Guntur that was collected from 1995 until 2007 that consist of 4800 seismograms. Analyses using the spectral fitting and spectral ratio methods generally depict the same anomalous areas. Studies using P and S waves indicate that the area of high attenuation corresponds to the area of low velocity that extending from mount Guntur to Kamojang caldera. In terms of the image quality, it can be seen that the attenuation derived using the spectral ratio of S wave has the same pattern with the one derived using P wave. This is due to the attenuation of S wave, which was derived directly from the P-wave. The Q value in the spectral ratio method depends on the width of the frequency window taken and the effect of noise in the determination the slope of the linear relationship between the natural logarithm of spectral ratio with frequency. The result of the spectral fitting analysis shows that the pattern of S wave attenuation image is different from the pattern inferred from the P wave data, because each attenuation image has been determined separately and does not depend on each other. Since the sensitivity of the values of Qp and Qs are important in fluid rock identification, the determination of Qs should not depend directly on Qp. With the various reasons above and more influential factor in estimating the value of Q using spectral ratio, the spectral fitting method is more recommendable to be employed to determine the value of Q.

Velocity versus Offset (VVO) Estimation Using Local Event Correlation and Its Application in Seismic Processing & Analysis Supriyono, S.; Priyono, Awali; Triyoso, Wahyu; Mardiyan, Hilman
Journal of Engineering and Technological Sciences Vol 45, No 2 (2013)
Publisher : ITB Journal Publisher, LPPM ITB

Conventional velocity analysis is usually done in a relatively spare grid, for instance every half kilometers, during the processing of seismic data. It is very laborious work and very subjective. To deliver an accurate velocity picking, processing geophysicists must have a good understanding of geological background of area being analyzed and experiences. Velocity errors often occur during picking. Proper quality control and checking are a must. A good and reliable velocity field is very important in seismic processing for achieving high-quality seismic images as well as for delivering an accurate depth conversion. The new method presented here, was developed to correct velocity errors automatically by means of residual velocity correction, and to produce an offset-dependent RMS velocity field at the same time. The method is data driven, based on the normal move out equation (NMO) and measuring the local even correlation between adjacent traces. The stacking velocity is derived simply by averaging the velocity field. The proposed method was tested on synthetic and real data examples with good result. The velocity field has certain characteristics related to hydrocarbon presence. Supriyono (2011 and 2012) developed a new DHI method using velocity gradient attributes by cross-plotting the velocity versus offset (VVO). The velocity gradient exhibits high anomalous values in the presence of gas.

Velocity versus Offset (VVO) Estimation Using Local Event Correlation and Its Application in Seismic Processing & Analysis S. Supriyono; Awali Priyono; Wahyu Triyoso; Hilman Mardiyan
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2013.45.2.2

Conventional velocity analysis is usually done in a relatively spare grid, for instance every half kilometers, during the processing of seismic data. It is very laborious work and very subjective. To deliver an accurate velocity picking, processing geophysicists must have a good understanding of geological background of area being analyzed and experiences. Velocity errors often occur during picking. Proper quality control and checking are a must. A good and reliable velocity field is very important in seismic processing for achieving high-quality seismic images as well as for delivering an accurate depth conversion. The new method presented here, was developed to correct velocity errors automatically by means of residual velocity correction, and to produce an offset-dependent RMS velocity field at the same time. The method is data driven, based on the normal move out equation (NMO) and measuring the local even correlation between adjacent traces. The stacking velocity is derived simply by averaging the velocity field. The proposed method was tested on synthetic and real data examples with good result. The velocity field has certain characteristics related to hydrocarbon presence. Supriyono (2011 and 2012) developed a new DHI method using velocity gradient attributes by cross-plotting the velocity versus offset (VVO). The velocity gradient exhibits high anomalous values in the presence of gas.

Implementation of Filter Picker Algorithm For Aftershock Identification of Lombok Earthquake 2018 A. Ardianto; Y.M. Husni; A. D. Nugraha; M. Muzli; Z. Zulfakriza; H. Afif; David P. Sahara; Sri Widiyantoro; Awali Priyono; Nanang T. Puspito; Pepen Supendi; A. Riyanto; Shengji Wei; B. S. Prabowo
Jurnal Geofisika Vol 17 No 1 (2019): Jurnal Geofisika
Publisher : Himpunan Ahli Geofisika Indonesia (HAGI)

The ability to identify earthquake events that are consistent, efficient and accurate is increasingly needed along with the increase in the amount of data analyzed. In this paper a filter picker algorithm is implemented to identify aftershock events and determination of arrival time automatically, especially for the P wave phase. Here modifications are made in determining the uncertainty of arrival time and there are additional criteria in determining the time of arrival used. The additional criteria are that in a certain time span, there are at least 5 stations determined by the time the filter picker arrives. This is done to minimize identification errors due to local noise and other practical reasons, namely the minimum number of stations to determine the location and other seismological analysis. To test the filter picker algorithm, aftershock data from the Lombok earthquake occurred on July 29 (M 6.4), August 5 (M 7), and August 19 (M 6.3 and M 6.9) 2018. The aftershock data were used for 30 days, from August 4, 2018 to September 4, 2018 using local seismic station in Lombok Island. The results of the filter picker algorithm were evaluated by comparing the number of earthquake events detected and the accuracy of determining the P wave arrival time automatically to the results of manually arriving time. In addition, a comparison of the results obtained from a broadband type seismometer with a short period is used to find out how much influence the type of tool has on its performance results. The results of the comparison with the manual arrival time show that more than 85 percent of the results of the automatic arrival time have a difference below 0.2 seconds. Therefore, it can be said that the filter picker algorithm is quite effective for identifying events and determining the arrival time of P waves. In this paper it is also shown that this algorithm can be used for broad band and short period seismometer sensor, even without the prior correction of instruments.

THIN BED IDENTIFICATION IMPROVEMENT USING SHORT – TIME FOURIER TRANSFORM HALF – CEPSTRUM ON “TG” FIELD Intan Andriani Putri; Awali Priyono
PETRO:Jurnal Ilmiah Teknik Perminyakan Vol. 8 No. 3 (2019): SEPTEMBER
Publisher : Jurusan Teknik Perminyakan Fakultas Teknologi Kebumian dan Energi Universitas Trisakti

Thin Bed Identification is still a difficult task even with the advanced technology of seismic acquisition. Certain high frequency component is necessary and could be obtained through resolution enhancement. Short – Time Fourier Transform Half Cepstrum (STFTHC) is performed to enhance seismic resolution thus a better separation of thin bed could be improved. Basic principal of STFTHC is to replace the frequency spectrum by its logarithm while phase spectrum remains the same. Synthetic seismic was built based on Ricker and Rayleigh criterion. They were used to test the program yielding a better separation of two interfaces under tuning thickness without creating new artifacts. The algorithm was applied to seismic data from TG field. Using post-STFTHC seismic data as input of acoustic impedance inversion, well tie correlation increases by 10% and decreases inversion analysis error by 17,5%. Several thin bed -which once could not- could be identified on acoustic impedance result.

Reducing Numerical Dispersion with High-Order Finite Difference to Increase Seismic Wave Energy: - Syamsurizal Rizal; Awali Priyono; Andri Dian Nugraha; Mochamad Apri; Mochamad Agus Moelyadi; David Prambudi Sahara
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2023.55.4.5

The numerical dispersion of 2D acoustic wave modeling has become an interesting subject in wave modeling in producing better subsurface images. Numerical dispersion is often caused by error accumulation with increased grid size in wave modeling. Wave modeling with high-order finite differences was carried out to reduce the numerical error. This study focused on variations in the numerical order to suppress the dispersion due to numerical errors. The wave equation used in modeling was discretized to higher orders for the spatial term, while the time term was discretized up to the second order, with every layer unabsorbed. The results showed that high-order FD was effective in reducing numerical dispersion. Thus, subsurface layers could be distinguished and observed clearly. However, from the modeling results, the wave energy decreased with increasing distance, so the layer interfaces were unclear. To increase the wave energy, we propose a new source in modeling. Furthermore, to reduce the computational time we propose a proportional grid after numerical dispersion has disappeared. This method can effectively increase the energy of reflected and transmitted waves at a certain depth. The results also showed that the computational time of high-order FD is relatively low, so this method can be used in solving dispersion problems.

Inversi Seismik Model Based (AI) untuk Karakterisasi Reservoar Sub-Formasi SAND4 Lapangan Penobscot, Kanada Sukri, Muh. Riswan Anas; Priyono, Awali; Multi, Warni
Tanah Goyang : Jurnal Geosains Vol 2 No 1 (2024): Tanah Goyang : Jurnal Geosains
Publisher : Program Studi Teknik Geofisika, Universitas Pattimura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/tanahgoyang.2.1.22-36

Prospek Lapangan Penobscot berlokasi di Sub-basin Sable di Utara Pulau Sable. Pada lapangan ini didukung oleh sumur L-30. Meskipun pada Lapangan Penobscot ini telah diketahui perkiraaan kedalaman lapisan sandstone pada Formasi Mississauga, data ini masih terlalu lemah untuk dijadikan acuan perkiraan persebaran lapisan reservoir sandstone yang ada. Maka dari itu perlu dilakukan seismik inversi (Model based) untuk menghasilkan volume acoustic impedance, volume porositas dan volume densitas sebagai landasan dalam mengambil tindakan terhadap reservoar. Zona target berada di Formasi Mississauga pada sub-formasi Sand4. Pada proses inversi acoustic impedance didapat nilai korelasi sebesar 0.951745 dan error 0.312563. Berdasarkan hasil inversi seismik menunjukkan zona sandstone memiliki nilai acoustic impedance rendah (7874 - 8923 (m/s)*(g/cc)) dan pada penampang volume porositas yang dihasilkan terlihat bahwa zona sandstone memiliki porositas relatif tinggi yaitu 22 – 26.3 %, serta pada penampang volume densitas menggambarkan zona sandstone memiliki densitas yang rendah berkisar 2.23 – 2.37 g/cc.

Inversi Seismik Model Based (AI) untuk Karakterisasi Reservoar Sub-Formasi SAND4 Lapangan Penobscot, Kanada Sukri, Muh. Riswan Anas; Priyono, Awali; Multi, Warni
Tanah Goyang : Jurnal Geosains Vol 2 No 1 (2024): Tanah Goyang : Jurnal Geosains
Publisher : Program Studi Teknik Geofisika, Universitas Pattimura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/tanahgoyang.2.1.22-36

Prospek Lapangan Penobscot berlokasi di Sub-basin Sable di Utara Pulau Sable. Pada lapangan ini didukung oleh sumur L-30. Meskipun pada Lapangan Penobscot ini telah diketahui perkiraaan kedalaman lapisan sandstone pada Formasi Mississauga, data ini masih terlalu lemah untuk dijadikan acuan perkiraan persebaran lapisan reservoir sandstone yang ada. Maka dari itu perlu dilakukan seismik inversi (Model based) untuk menghasilkan volume acoustic impedance, volume porositas dan volume densitas sebagai landasan dalam mengambil tindakan terhadap reservoar. Zona target berada di Formasi Mississauga pada sub-formasi Sand4. Pada proses inversi acoustic impedance didapat nilai korelasi sebesar 0.951745 dan error 0.312563. Berdasarkan hasil inversi seismik menunjukkan zona sandstone memiliki nilai acoustic impedance rendah (7874 - 8923 (m/s)*(g/cc)) dan pada penampang volume porositas yang dihasilkan terlihat bahwa zona sandstone memiliki porositas relatif tinggi yaitu 22 – 26.3 %, serta pada penampang volume densitas menggambarkan zona sandstone memiliki densitas yang rendah berkisar 2.23 – 2.37 g/cc.

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