Analysis of the influence factors of tight reservoir start-up pressure difference

Abstract

Tight gas reservoir is not only characterized by low permeability, but also by high water saturation. This paper was studied on the basis of tight reservoir microscopic pore structure analysis, through gas depletion-drive development simulation experiments of constant rate production and constant pressure difference two ways, analyzed the influence factors of reservoir starting pressure difference, to explore the change law of tight reservoir start-up pressure. The study suggests that the pore structure throat radius of tight reservoir is small, and the throat occupies a large proportion of pore volume, and the throat is not only the seepage channel but also the important storage space. The experiment also shows that the throat radius, water saturation and effective stress are the main factors to determine the starting pressure difference of reservoir. So in the development process, some measures have been taken to reduce or control the start-up pressure near wellbore area such as well location optimization, perforating optimization, increasing fracturing fluid flowback rate and drainage gas recovery measures optimization, these measures have achieved positive effect in Sulige gas field.