Cuong T. Q. Dang

Gelation Time Optimization for an HPAM/Chromium Acetate System: The Successful Key of Conformance Control Technology

Abstract Gelation of gelant solutions occurs under specific conditions. The gelation time can vary from several minutes to several days, even a few months, depending on parameters, such as temperature, polymer type, polymer concentration, cross-linker concentration, initial pH, salt type, and salt concentration. Therefore, many laboratory experiments were studied to understand the gelation time before the core flooding experiments were carried out. The polyacrylamide polymers and the chromium acetates were mixed to form the gelant solutions. The results suggested the good proportion of polymer to cross-linker for the next core flooding experiments and the effects of gelation time.

Geological uncertainty and effects of depositional sequence on improved oil recovery processes

Several emerging improved oil recovery (IOR) techniques have been proposed in the past decades with promising results. However, a systematic study of reservoir heterogeneity on these advanced processes has not yet been presented. This paper provides one of the first comparative evaluations of the effects of reservoir heterogeneity on various IOR processes from the conventional methods (waterflooding, CO2 flooding) to the emerging recovery technologies (Low-Salinity Waterflooding and CO2 Low-Salinity WAG) for wider and more successful implementation of these projects. Since weakness exists in the current simple and unrealistic models, detailed geostatistic models are employed to provide a more realistic and unbiased evaluation of reservoir heterogeneity. A new modeling approach that involves the integration of geological software, a reservoir simulator and a robust optimizer in a closed loop for generating multiple geologically driven realizations and uncertainty assessment of different recovery processes is introduced. Then a series of numerical simulations is conducted to investigate the influences of FU and CU sequences on oil recovery. Finally, the uncertainty range of reservoir heterogeneity is thoroughly evaluated using a large number of geological realizations with significant differences on porosity and permeability distributions. The effect of the Kv/Kh (aspect) ratio is also addressed in this study. The simulation results indicate that the depositional sequence has a dominant effect on oil recovery in all recovery processes. The CU distribution demonstrates superior performance over the FU distribution.

An integrated geology and reservoir engineering approach for modelling of a giant fractured basement reservoir

A great portion of the worlds oil reserves is contained in naturally fractured reservoirs (NFRs). As the conventional oil and gas reservoirs have become significantly depleted whereas energy demand sharply increases, the NFRs play an important role in oil exploration and make a large contribution toward oil and gas production worldwide. This paper aims to introduce a historical case study of a successful development plan for a giant fractured granite basement reservoir with a unique geological characterisation. A better geological understanding about the complexity of such a naturally fractured basement reservoir is provided within a simulation strategy in order to optimise successfully its oil exploitation. With our rich experiences in exploration and production of hydrocarbons in fractured basement granite rock for more than 20 years, it is a valuable case study for both current and future development planning of basement reservoirs elsewhere in the world. [Received February 5, 2013; Accepted November 25, 2013].

Sedimentological Process and Sequence Stratigraphy Analysis of Ngrayong Sandstone Formation, Northeast Java Basin

Abstract The Ngrayong Formation has been studied for a long time. However, the depositional environment of the Ngrayong Formation has been determined differently from one author to another. Therefore, more in-depth studies about Ngrayong Formations deposition environment were attractive. The measure section was carried out along the Braholo River from Ngampel to Sendangharjo villages for vertical profile lithologic column. Depositional environment was studied in terms of sedimentology of Ngrayong Formation. Sedimentology was emphasized on foraminifera, trace fossil, grain size, and petrographic analysis. Porosity and permeability of the Ngrayong Formation sandstone was also calculated to evaluate reservoir quality. Porosity and permeability were measured by consolidation permeameter.