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Indonesian’s Natural Gas: Production, Reserves, and Challenges Widarsono, Bambang
Indonesian Journal of International Law
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (841.54 KB)

Abstract

In the last few years it has occurred the decreasing of Indonesia’s oil production in national scale in 10% per year. At the same time the situation of the national gas showing the increasing of the production and the backup. The production rate can be maintained and the backup even can show the growth from year to year. The analysis of the history of the production and the backup, exploration activity, and the comparison between the discovery of the oil and gas in the recent years underlying that the oil can be the sources of energy and the income for the state. Even will facing some challenge in oil exploitation in the term of the application of technology, infrastructure, law enforcement, social unrest, strict regulation, and incentives. That challenge must be overcome if the gas production, and also oil, to achieve the sustainable.
Choice Of Water Saturation Model In Log Analysis And Its Implication To Water Saturation Estimates – A Further Investigation Bambang Widarsono
Scientific Contributions Oil and Gas Vol. 35 No. 3 (2012): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.35.3.30

Abstract

Water saturation is one of the most important governing factors in hydrocarbon in place and reserves estimation. Error in the estimation of water saturation may signifi cantly impose bias in the estimation of both quantities. In spite of there are various factors affecting potential error in water saturation estimation, choice in water saturation model(s) appears to play an important factor. This study involves eight water saturation models that are widely used in log analysis up until today. Using the same input data, the eight models have proved themseleves to have produced different water saturation estimates. Using a moderate level of water saturation error of 20% evaluation may result in up to 50% error in the reserves estimates. Observing the wide disparities in the estimated water saturation values yielded by the models used in this study, errors higher than 50% may take place. This evidence should strengthen our awareness over the potential error and careful applications of model(s) – and validation of results – that have to be observed.
Reducing Uncertainty In Log Analysis Due To Presence Of Heavy-Conductive Minerals In Sendimentary Rocks Bambang Widarsono
Scientific Contributions Oil and Gas Vol. 23 No. 1 (2000): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.23.1.121

Abstract

Presence of heavy-conductive mineral(s) in formation rocks tends to provide negative influence to some log readings especially the resistivity log. With regard to its function in log analysis, any distortion in resistivity log readings will certainly lead to potential misinterpretation on petrophysical properties such as water saturation (S.) Therefore a method dedicated to minimizing the effect is indeed necessary. This paper presents results of a study on presence of heavy-conductive minerals, distributed in structural form, on resistivity reading. Based on analogy and expansion of a structural clay distribution model, a correction method plus its application procedure have been proposed. Since the method is develop using an approach that is considered valid in general term it is, therefore, conceptually applicable to any field cases as long as its theoretical conditions are met. In order to make application of the method easier it has also been presented in form of nomographs. Application of the method on log analysis of two wells in West Java has proved itself well in which corrections on calculated water saturation have yielded values that are more consistent when compared to production test data. The method is also prepared in a manner that it can be easily integrated into standard log analysis practices.
In-Situ Stresses In Rock Masses: A General Review Bambang Widarsono
Scientific Contributions Oil and Gas Vol. 23 No. 2 (2000): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.23.2.126

Abstract

The in situ state of stress is a rock's point-to-point property that must be taken into consideration in every subsurface engineering activity This has been realized to an increasing extent over the past 10 - 20 years. Good quality in situ stress information enhances the quality of engineering designs such ax for mining, petroleum and geothermal production. In turn good engineering designs will support the process of decision making in related industries. However, efforts are required to encourage the use and integration of this information into the engineering activities. This paper is basically a general review over the in situ stress that encompasses various aspects, among others are concept, causes/sources that generate it, influencing factors, the effect of scales, techniques for measuring it, and its distribution throughout the lithosphere. The review is supported by works and conclusions that have been made by various investigators in the past. The relative absence of the use of in situ stress information in petroleum engineering practices in Indonesia is also discussed. This includes the absence of demand upon the information, probable consequence, and the field cases that are likely caused by the absence. Apart from the importance of in situ stress information shown by the review, it has also prompted the need to apply proper use of in situ stress information in relation to the corresponding engineering scales. Inappropriate measurement techniques assigned to an engineering problem, which corresponds to a certain scale, will certainly lead to a serious misprediction over the expected outcome. These all are hoped to provide operators in the industry a complete general view over the in situ stresses their importance.
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.
IMBIBITION WATER-OIL RELATIVE PERMEABILITY: INTRODUCTION OF WETTABILITY STRENGTH FOR ENHANCING MODEL ROBUSTNESS Bambang Widarsono
Scientific Contributions Oil and Gas Vol. 42 No. 1 (2019): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.42.1.172

Abstract

Water-oil relative permeabilty information of hydrocarbon reservoir rocks plays important roles in various modeling activities related to reservoir modeling and production forecast. The imbibition relative permeability scheme - the process of concern in this study affects many dynamic processes in reservoir. Water flooding and water encroachment form aquifer to oil zone in the reservoir are two two examples which representation in reservoir model requires the data. This study uses the standard Corey relative permeability model as a tool to study and model imbibition relative permeability behaviour of some reservoir rocks in Indonesia. Laboratory data from as many as 340 rock samples - sandstones and limestones - of various permeability and wettability from various oil fi elds in Indonesia is used. Activities in the modeling has pointed out the need to introduce two new empirical factors that relate to rock wettability and non- wetting fl ow hindrance to the model. The two factors appear to have signifi cantly improved the ability of the model to agree and match to the measured data. The modeling also produces suggested values of the factors for rock groups based on rock wettability type and strength, as well as on permeability categories. Comparison between modeling results before and after modifi cation has shown signifi cant improvement in validity of output.
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.
THE ROCK COMPRESSIBILITY CHARACTERISTICS OF SOME INDONESIAN RESERVOIR LIMESTONES Bambang Widarsono
Scientific Contributions Oil and Gas Vol. 37 No. 1 (2014): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.37.1.205

Abstract

Rock compressibility is an important formation rock properties. It infl uences various processesin reservoir and rock formations that encompass from sources of reservoir driving energy, changes inother reservoir properties, to land subsidence. Various studies have been performed and published, butno comprehensive studies have ever been performed on Indonesian reservoir rocks. This article presentsresults of such studies on Indonesian limestones, reservoir rocks that have contributed much to Indonesia’snational oil and gas production for decades. The study was carried out in order to study the characteristics oflimestone in its relation to rock porosity. A set of 84 limestone samples taken from fi ve productive formationsin Indonesia is used in the study. Some existing and widely known mathematical correlations/models are alsoused to assist the study. Some of the results show that the existing models are not always valid for some ofthe rocks, and therefore a new model is proposed for medium-hard and vuggy limestones. The results alsoshow that limestone characteristics are not related to rock types and place of origin, but instead to rockhardness and degree of vuggy pore presence.