Abstract. Water injection has been employed in the Tempino oil field since 1996. The current oil recovery factor is 35% of OOIP. Even though the pressure is still high, the oil production rate has declined rapidly and the water cut is approaching 89%. In order to mobilize the oil from the reservoir more effectively, surfactant flooding is one of the solutions that can reduce residual oil saturation. Interaction between crude oil and compatible surfactant generates microemulsion, as an indication of low interfacial tension. Hence the oil is expected to move out of the pore throat easily. In this research, thirty types of surfactants were evaluated. The hydrophilic lipophilic balance (HLB) was calculated and the interfacial tension (IFT) with the reservoir fluid was measured. HLB criteria were established as an indicator of low IFT, which was then tested for Berea core flooding. The results indicate that an HLB between approximately 2.7 and 3.1 (on Davies' Scale) or greater than 11.5 (on Griffin's Scale) gives low IFT (~10 -3 dynes/cm). This characteristic is possesed by surfactant ethoxy carboxylate with a linear hydrophobic structure. This surfactant produces a high incremental oil recovery according to Berea core flood tests. The AN2NS and AN3 surfactants recovered 90% and 86% of OOIP respectively.

This paper presents the application of a new concept, i.e.; fractal model, to analyze pressure transient test data in complex naturally fractured geothermal reservoir. Application of conventional type curves has been unsuccessful in analyzing and interpreting the interference test results in Kamojang geothermal reservoir which is considered as a complex naturally fractured system. Using the conventional type curve method, the pressure test data, in this case, cannot match to the curve, primarily at early time data. The match, however, can be achieved by using the type curves generated based on "fractal reservoir model" which has been previously developed by Chang and Yortsos in 1990. Using the diffusivity equation of fractal reservoir, the equation for interference test has been derived and the result is then used for generating a new type curve method. In addition, the procedure to use this method has also been developed. Using the generated type curves, application has been performed on analyzing the interference test data from Kamojang geothermal reservoir. The analyzing results demonstrate the viability of the model in describing characteristics of the reservoir such as transmissibility, storativity and fractal dimension of the medium. Introduction Previous work showed that the fractal reservoir model could be used satisfactorily in describing the pressure transient behavior in the reservoir. In their model, the fracture network is assumed to be connected and distributed as a fractal object within a homogeneous medium (matrix) of Euclidean geometry. Fluid flow from reservoir to wells, in such a reservoir, occurs only through the perfectly connected fracture network. Based on these approaches, they used diffusivity equation to model a transient flow in the fractal reservoir for single well problems. In this paper, the application of fractal reservoir model for handling the multiple well problems, especially in analyzing the interference test data, is discussed. Physical and mathematical descriptions of this model are basically adopted from the model that had been developed by Chang and Yortsos (1990). By involving several mathematical manipulations into the model, the formulation can be extended and used for multiwell test problems. Then, using this equation, type curve model for interference test analysis can be generated by plotting two variable groups which have been defined in this study. The interference test data in Kamojang geothermal reservoir which is considered as a complex naturally fractured reservoir has been analyzed to determine transmissibility, storativity and fractal dimension of the reservoir. DEVELOPMENT OF THE PROPOSED MODEL The fractal model is able to appropriately described the complex naturally fractured reservoir which has a large number of different scale, poor fracture connectivity and disorder spatial distribution. In the pressure transient case, the application of fractal model has been examined by Acuna et al. for analyzing single well test data in naturally fractured reservoir of geothermal field. Using their model, the method that could be used in the Interference Test Analysis was developed. By considering at least two interference wells in a fractal reservoir, one of them is an active well and the others are observation wells (see Figure 1), a pressure transient equation has been formulated in this study. Using this equation, a procedure of type curve matching is then proposed for analyzing some reservoir parameters, such as reservoir transmissibility, storativity and fractal dimension. P. 511^

A nonisothermal, ID, compositional, two-fluid, multiphase hydrodynamic model is used to describe the incipient formation and dynamic behavior of condensate in a natural-gas pipeline with undulating topology. The 26-in. [66-cm] -diameter case-study transmission pipeline traverses 180 elevation changes in its 30. 72-mile [49.4-lan] span. Results demonstrate the predictive and descriptive potential of the model in field applications and the significant effect of inclination and inclination changes on the hydrodynamics of gas/condensate flow in transmission pipelines. The model presented can serve both predictive and design purposes. IntroductionTwo-phase flow in natural-gas transmission pipelines is common. Accurate knowledge of the pressure profile and liquid distribution as predicted with an appropriate model is necessary for optimal design and siting of compressor stations and liquid catchers along the pipeline. Therefore. it is imperative to design such pipelines with appropriate models capable of predicting and handling two-phase fluid dynamics in pipelines. Such an approach is especially critical in the design of long-distance pipelines where the interactions between the two phases, coupled with varying inclinations, can significantly affect the pressure profile along the pipeline.Various approaches have been developed to describe the fluid dynamics of two-phase flow in pipe. Most are basically empirical and/or semiempirical, lack generality, and contain predictive inadequacies. Adewumi and Bukacek! reviewed these methods in detail. More-recent attempts have used a fundamental hydrodynamic approach to describe multiphase flow in pipes. This approach has been successful in a number of cases that are well documented in the literature. Refs. 2 through 4 report other examples of the use of this approach to solve practical problems of engineering interest.In this study, a numerical simulation package for two-phase flow in pipe was developed by coupling the hydrodynamic model and the phase-behavior package. The hydrodynamic formulation is a modification of the two-fluid model. Detailed formulation of the two-fluid model that uses the basic principles of continuum mechanics coupled with the volume-averaging technique is reported elsewhere. 2 A modified Peng-Robinson 5 equation of state (EOS) is used to describe the fluid phase behavior.A detailed analysis of the basic hydrodynamic equations used in this study was presented in Ref. 4, but the effects of gravitational force in the momentum equations are not included because that study was intended for horizontal pipelines. Several features distinguish the behavior of inclined transmission lines from that of horizontal pipes. In inclined pipeline, the effect of gravitational force must be taken into account in the hydrodynamic formulation, even for a very small inclination, because the gravitational force significantly affects the liquid velocity, the pressure gradient, and invariably the liquid holdup. Sharp changes in liquid velocity may occur several times in a pipe...

This paper presents the application of a new concept, i.e.; fractal model, to analyze pressure transient test data in complex naturally fractured geothermal reservoir.Application of conventional type curves has been unsuccesful in analyzing and interpreting the interference te,;l results in Kamojang geothermal reservoir which is considered as a complex naturally fractured system.Using the conventional type curve method, the pressure test data, in this case, can not match to the curve, primarily at early time data. The match, however, can be achieved by using the type curves generated based on "fractal reservoir model" which has been previously developed by Chang and Yortsos in 1990. Using the diffusivity equation of fractal reservoir, the equation for interference test has been derived and the result is then used for generating a new type curve method. In addition, the procedure to use this method has also been developed.Using the generated type curves, application has been performed on analyzing the interference test data from Kamojang geothermal reservoir.The analyzing results demonstrate the viability of the model in describing characteristics of the reservoir such as transmissibility, storativity and fractal dimension of the medium.

Oil and gas industry is one of the most capital-intensive industry in the world. Each step of oil and gas processing starting from exploration, exploitation, up to abandonment of the field, consumes large amount of capital. Optimization in each step of process is essential to reduce expenditure. In this paper, optimization of fluid flow in pipeline during oil transportation will be observed and studied in order to increase pipeline flow performance.This paper concentrates on chemical application into pipeline therefore the chemical can increase overall pipeline throughput or decrease energy requirement for oil transportation. These chemicals are called drag reducing agent, which consist of various chemicals such as surfactants, polymers, nanofluids, fibers, etc. During the application of chemical into pipeline flow system, these chemicals are already proven to decrease pump work for constant flow rate or allow pipeline to transport more oil for same amount of pump work. The first application of drag reducer in large scale oil transportation was in Trans Alaskan Pipeline System which cancel the need to build several pump stations because of the successful application. Since then, more company worldwide started to apply drag reducer to their pipeline system.Several tedious testings on laboratory should be done to examine the effect of drag reducer to crude oil that will be the subject of application. In this paper, one of the testing method is studied and experimented to select the most effective DRA from several proposed additives. For given pipeline system and crude oil type, the most optimum DRA is DRA A for pipeline section S-R and for section R-P is DRA B. Different type of oil and pipeline geometry will require different chemical drag reducer.