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A SIMPLE APPROACH FOR UNDERSTANDING SEISMIC WAVE PROPAGATION IN POROUS MEDIA Fakhriyadi Saptono; Suprajitno Munadi
Scientific Contributions Oil and Gas Vol. 22 No. 2 (1999): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.22.2.117

Abstract

A simple approach for understanding seismic wave propagation in, porous media has been developed based on the effect of stress gradient on compressibility of the matrix and the fluid. The fluid saturation is accommodated in the bulk density formulation. The approach started from Gassmann theoretical formulation followed by simplifying the mathematical detail by substituting their physical aspects. Finally a practical formula for core analysis purposes is introduced. The theoretical concepts and experimental results appear to be in a good agreement.
ESTIMATING POROSITY AND WATER SATURATION FROM SEISMIC/ACOUSTIC SIGNALS: A CORRECTION ON THE EFFECT OF SHALINESS Bambang Widarsono; Fakhriyadi Saptono
Scientific Contributions Oil and Gas Vol. 23 No. 3 (2000): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.23.3.131

Abstract

The presence of shale in sedimentary rocks tends to introduce complexity in any formation evaluation activities. This is also the case when efforts are spent in estabilishing a method that enables analysts to estimate porosity and water saturation from seismic survey.
Application of Artificial Neural Network for Assisting Seismic-Based Reservoir Characterization Bambang Widarsono; Fakhriyadi Saptono; Patrick M Wong; Suprajitno Munadi
Scientific Contributions Oil and Gas Vol. 25 No. 1 (2002): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.25.1.138

Abstract

Reservoir rock physical properties, such as porosity and water saturation, always play prominent roles in the development of oil and gas fields. Accurate information regarding their distribution is always desired. For this new approach that uses a purpose, a combination of intelligent computing (artificial neural network or ANN) and rock physics, with a full utilization of core data, well logs and seismic-derived attributes, is proposed. The method is basically an effort to link the required rock physical properties to seismic- derived attributes through the use of rock physics theories. The ANN itself is used to fill the gaps of data array required by the proposed method through its capacity for pattern recognition. The proposed method is applied to a limestone reservoir in East Java. Validation is carried out by comparing the results to the observed data at well locations as well as by geological justification. The application has shown a new potential for supporting reservoir modeling and field development.
An Bambang Widarsono; Fakhriyadi Saptono; Heru Atmoko
Scientific Contributions Oil and Gas Vol. 26 No. 1 (2003): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.26.1.176

Abstract

Rock true resistivity (Rt) is known as more sensitive than compressional-wave velocity (Vp), the principal output of a seismic survey, to variation in water saturation. Therefore, it would be of a great value if there were a way to predict resistivity distribution from seismic signals. This study is essentially an effort to see the possibility of predicting Rt from Vp through a pattern recognition approach. For the purpose, a series of laboratory tests were performed on some Central Sumatran clay-free sandstone samples of various porosity values and at various water saturation levels. For studying the pattern of relationship, artificial neural networks (ANNs) were applied. From the ‘training’ (i.e.pattern recognition) activity performed using the ANNs, it has been show between Vp and Rt in the following ‘blind test’, it has also been shown that the trained relationship can be used to estimate Rt reliably using other data as input. Comparisons between estimated and observed Rt data have indicated good agreement implying the success of the approach taken in the study. This has laid the foundation and justification for further application of the approach on seismic and well-log data.
A PROPOSED METHOD FOR OBTAINING INTER-WELL TRUE RESISTIVITY (R) FROM SEISMIC DATA – A FIELD TRIAL Bambang Widarsono; Fakhriyadi Saptono
Scientific Contributions Oil and Gas Vol. 26 No. 2 (2003): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.26.2.190

Abstract

Information about spatial distribution of rock true resistivity (Rt) throughout an oil or gas field is always desired.
FUZZY LOGIC AS A TOOL FOR ESTIMATING PRODUCTION POTENTIAL OF A SAND LAYER Bambang Widarsono; Heru Atnwko; Fakhriyadi Saptono; Tunggal; Ridwan
Scientific Contributions Oil and Gas Vol. 27 No. 3 (2004): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

In production management, a prior knowledge overproduction potential of acandidate sand layer (geologi-cal complexity in Indonesia has led toexistenceof strati-fied reservoirs with a set of layers) to be opened is al-ways desirable.
Apakah Estimasi Porositas dari Log Akustik Cukup Akurat untuk Batuan yang Tersaturasi Secara Parsial – Sebuah Alternatif Sederhana untuk Mengurangi Heru Atmoko; Rosidelly Rosidelly; Bambang Widarsono; Fakhriyadi Saptono
Lembaran Publikasi Minyak dan Gas Bumi Vol. 38 No. 1 (2004): LPMGB
Publisher : BBPMGB LEMIGAS

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Abstract

Dalam memperkirakan harga besaran porositas dapat digunakan bermacam-macam metode, antara lain dengan merambatkan gelombang akustik pada media berpori dengan memberikan interpretasi kecepatan gelombang tersebut. Pada tahun 1956 Wyllie dkk mengajukan persamaan waktu rata-rata (time average), yang merupakan hubungan linier antara waktu dan porositas berdasarkan hasil penelitian terhadap batuan pasir (sandstone) di laboratorium. Persamaan Wyllie di atas sebenarnya hanya berlaku pada kondisi dimana batuan yang diukur porositasnya mengandung hanya air saja, dengan porositas yang seragam, bersih dari lempung, dan kompak. Contoh yang dapat dianggap paling relevan adalah daerah di sekitar lubang bor. Fakta di sekitar lubang bor tersebut diperkirakan dapat menyebabkan bias dalam memperkirakan harga besaran porositas batuan karena asumsi yang lazim dalam menggunakan persamaan Wyllie adalah batuan tersaturasi secara penuh oleh satu jedis fluida saja. Beragamnya saturasi fluida di formasi ternyata dapat mempengaruhi akurasi perhitungan porositas yang dihasilkan dari log akustik. Untuk mendapatkan besaran porositas yang akurat diperlukan pemilihan waktu transit matriks batuan dan waktu transit fluida yang cukup mewakili. Suatu bentuk koreksi atas perhiitungan porositas akustik pada kondisi saturasi air kurang dari 100% telah dibangun beserta penerapan di laboratorium. Perlu dilakukan penelitian lebih lanjut terhadap litologi lainnya seperti pada formasi karbonat untuk mengetahui sejauh mana validasinya atas bentuk koreksian yang telah dibangun