Abstract

This article presents the experience of the application of the unified mechanistic model for multiphase flow hydraulic calculations in the wellbore for the means of monitoring and optimization of producing wells performance in Rosneft Oil Company.

Introduction

Well production maximization requires continuous monitoring of production wells regimes, analysis of well enhancement potential and possibility to obtain it. Solution of those tasks involves application of engineering hydraulic calculations: bottom hole pressure determination in naturally flowing and pumping wells, nodal analysis and well test analysis. The peculiar feature of all those calculations is that in most cases flow in a wellbore is multiphase. Since no exact solution for multiphase flow dynamics exists, we have to select from a larger number of existing approximation techniques. However, most of them have substantially limited range of applicability, for example for well deviation angle, for minimum flow rate, etc. On the other hand, we need to perform calculations for all the wells and for the wide range of operating conditions in the Company, so universal technique is required. Today, the only method that allows performing calculations for the entire range of parameters is the unified mechanistic model developed at the University of Tulsa in the framework of Tulsa University Fluid Flow Project (TUFFP). This article describes the best practices of that model application for engineering calculations performed to evaluate well productivity and to optimize well performance.

Production management in Oil Company

The major task for every oil company is to maximize oil production and to reduce operational costs. Permanent well production monitoring, picking out most promising wells and performing operations on those wells to increase production (well enhancement routines) are required to achieve maximum well performance. The key objective of well production monitoring is estimation of well production potential and comparing it to current well performance to measure current efficiency of well operation. Well potential is the maximum possible well production that can be reached considering all existing conditions and constraints. Efficiency of well operation is a measure of reaching well production potential and can be used to reveal possible sources of production increase. Well potential depends on possible set of treatments that could be applied to it. For example, the simplest treatment is decreasing the bottom hole pressure by changing pump setting depth and flow capacity. More complex ones are acidizing and hydraulic fracturing.

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