Analysis of common reservoir damage problems in coalbed methane wells and study on acid plugging removal agent system

Abstract

Reservoir damage is an important factor limiting the productivity of coalbed methane wells. In this paper, the coal seam in a coalbed methane producing area in the southeast edge of Ordos Basin is taken as the research object, and the types of reservoir damage in this block are analyzed through the composition test of coal samples and the comparison of production conditions, and the targeted solutions are given. The results show that the main types of reservoir damage in this block are solid plugging and water locking damage. The dissolution rate of acidic plugging removal working fluid with hydrochloric acid, hydrofluoric acid, acetic acid and hydrogen peroxide as main components for pulverized coal in this block reached 13.73%. After acidification, the permeability increased by 1.8~6.9 times, and the porosity increased by 0.35%~2.87%, indicating that the plugging removal working fluid system can effectively dredge the liquid seepage channel, reduce the seepage resistance and achieve the plugging removal effect.

Keywords

• coalbed methane
• reservoir damage
• acidic plugging remover
• experimental evaluation