Dynamic and quantitative Sensitivity analysis on the efficient development of tight oil

Abstract

The aim of this paper is to present dynamic and quantitative sensitivity analysis for the tight oil development with horizontal fracturing well. And a set of correlations predict the oil production and effective swept scope are built   correspondingly.

In this paper, a group of orthogonal schemes were designed and simulated with the CMG IMEX Simulator. And 11 parameters are filtered after extensive investigation of typical characteristics of tight oil in China and abroad. The parameters include reservoir characteristics, threshold pressure gradient and stress sensitive effect, fracturing parameters etc. And analysing each five years’ simulation results including cumulative production, oil recovery and effective flow area.

The analysis result shows that the initial reservoir pressure and well bottom hole pressure, which decides whether the energy is sufficient to drive oil flow, is the most significant factor to influence the tight oil cumulative production. Secondly, reservoir thickness and porosity influence whether the reservoir oil is rich. However, for the oil recovery, the contribution of fracturing is more essential, which directly determines whether it has industrial oil production. In addition, threshold pressure gradient and stress sensitivity, the distinct seepage characteristics between tight oil and traditional reservoirs, will further exacerbate the ultra-low permeability and seepage process. The most immediate effect is that the swept scope range becomes smaller. In addition, a series mathematical model are also established for the development effect estimation through the use of multivariate regression, Through data validation, the quantitative model error ranges 5.45% from 9.29%.

Keywords

• tight oil,sensitivity analysis,threshold pressure gradient,stress sensitivity

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