Abstract:

In order to clearly understand the characteristics of the vertical fracturing wells and multiple laterals horizontal wells in coal bed methane production,based on well drilling and completion,the measures and principles increasing production,in this paper,the production mechanism of two kinds of coal bed methane wells is stated.Based on the flowing characteristic of groundwater and well drilling and completion,combined with Darcy′s laws,the changing pressure models of two kinds of wells are gained.According to the supplying ability and primary task in every drainage stage,the working system in saturated water is divided into adjust process and steady falling liquid depth process,the working system in two-phases stream stage is divided into four processes,i.e.,adapt process of working system,steady falling pressure at the bottom of the well,steady production process and controlling pressure at the bottom of the well and production process.Finally,it is pointed out that attendant proceedings in the process of the well drilling and completion and production,these acquaintanceship is of guidance to the production of coal bed methane wells.

Key words: the vertical fracturing well, multiple lateral horizontal well, coal bed methane, drainage system, pressure transmission