Abstract

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.

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