The performance of pipeline transportation of oil & gas mixtures can be optimized by different ways. This paper introduces a synergetic statistical approach based on field data to analyzing the oscillations of pressure by determining simultaneously Hausdorff's Dimension "D", Hurst's Index "H" and the Entropies "E", as a useful tool for managing the multiphase pipeline transportation systems. Introduction Practically, in most cases, the pipeline transportation of oil & gas mixtures encounters the fluctuation in pressures and flow rates that can cause the complexities and instability in the oil and gas production and gathering systems. To improve the transportation conditions and to provide adequate safety for working pipelines the studies on implementation of a new approach to analyzing the dynamical system have been carried out. The results obtained in studies allow diagnosing the hydro-dynamical states of oil and gas flows in pipelines and its ordering. Consequently, it can help to transport the oil and gas mixture through existing pipelines at maximum flow rate but with minimum pressure losses. Background One of most important missions in pipeline transportation of oil and gas mixture is to improving hydraulic regimes based on forecasting the dynamical conditions. This may be achieved by regulating the flow regime or elimination of phase inhomogeneity of flows in the pipeline. The most effective way to settle the problems is to establish the principally new technologies allowing optimizing the solutions at minimum expenses for their practical realization. Transportation of production at maximum flow rate with minimum spending the energy through submarine pipelines represents the most important duty in operation of oil and gas pipeline network in offshore conditions for JV Vietsovpetro. Necessary condition for solving this dilemma is to operating the pipelines at lowest level of pulsation and minimum hydraulic losses. This may be executed by preliminary gas separation from oil or excluding most of resources influencing on stability of dynamical state of system. In conjunction with this, the execution of field experiments in working pipelines would require unproductive expenditures of finance as well as time. More and more attention is paid on development of method diagnosing the state of an object using data collected during routine operation. Accidental fluctuations, occurring in hydraulic systems, often have determined character. They happen due to own system and can serve as resource of information on internal characteristics. The existence of factors affecting on stability of working regime in pipeline, such as: gas flow rate ratio, flow rate, pipe size, depositions, leads to occurrence of oscillatory movement that heap on pulsations of pressure and flow rate. Meanwhile, they change the spectra and other characteristics of initial noises. So that the analysis of pulsations allowing finding out those changes, can lead to diagnosing the degree of inhomogeneity of being studied system. Because the oscillations of pressure and flow rate have more significant chaostic character, hence for their analysis the latest achievement in the theory of dynamical chaos is to be involved.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractTransport of oil and gas from producing wells to separation units in two-phase flow by one pipeline could significantly reduce the budget for building the product gathering system. However, practice and studies showed that it would be effective only if the gas flow rate ratio β≤ 0.7.JV Vietsovpetro crude oil, mainly being produced from the basement of southern part of the White Tiger field, is transported in form of two-phase flow from Satellite Platforms (SP) to Central Processing Platform (CPP) for gas separation through submarine pipeline (without thermal insulation). The crude has high wax content (up to 27% by weight), high pour point temperature 33-34 o C, and average GOR of 166 m 3 /m 3 @ 20 o C & 100 kPa(a). The transport and gas separation processes encountered many difficulties due to pressure and flow rate fluctuations. Increasing pressure in the pipelines to 2200-2500 kPa(g) improved the situation, but not enough. A consequence was also that the well flow rates were decreased. This paper describes the results from a full-scale field test on transportation of 5848 m 3 /day (@ 20 o C & 100 kPa(a)) well product from SP to CPP as an oil and gas mixture. Studies were carried out on subsea un-insulated pipeline with OD 0.324m and length around 2000m, with gas flow rate ratios, varying from 0.623 to 0.868. Developed on the above basis the technology of preliminary gas separation on the SP and then transport of the gas and oil by two separate pipelines has assisted JV Vietsovpetro in elimination of a/m difficulties. Application of this technology would gain significant benefits when most of the wells on the SP moved to gaslift production.

Abstract. The paper presents the study results of intermittent gaslift. vertical flows using both experiment and theoretical models. To study the influence of rncdium thcrmophysical characteristics on the process efficiency, two gas-liquid systems arc used in the experiments. The obtained results show that there is a critical gas injection volume, less than that the liquid slug cannot reach the top of the tubing. Correlations for prediction of liquid entrainment in gas core are also shown for two presented gas-liquid systems. A modified dynamical model was developed. The model consists of a system of' differential equations. The resulting system of equations is numerically solved. The numerical code is verified by using experimental data and calculation data of the other authors. Finally, the effects of system parameters are studied.

ABSTRACT. In the paper the rheological properties of cr ude oil of White T iger oil-field (Vietnam) and its emulsion with sea-water, including measurement results and analytical approximation formulae for wide range of pressure, temperature and water concentration, are presented. As it is known, the crude oil of White Tiger oil-field is a high-paraffin and high-viscous oil. At the low temperature (T ~ 40°C) it behaves as non-Newtonian fluid of Bingham-Shvedov group. Therefore, beside the effective viscosity, the effective dynamic shear stress is also measured and approximated. The rheological properties of crude oil and emulsion of crude oil and water are also measured and approximated for the case when the mixture contains 0.1% chemical reagent ES-3363.