Wangjiatun Low Permeability Gas Field Production Technology Boundaries

Low pressure ,low permeability ,low abundance ,water-bearing gas reservoirs are widely distributed in china. According to incompletely statistics, about 80% reverse exists in this kind of gas reservoir. Therefore, it is important to exploit this kind of gas reservoir well. Since this kind of gas reservoir has unique characters, for example, some of them have compact formation, some of them have low permeability, some of them have initial pressure gradient while gas flow in the porous' media, some are driven by edge water and bottom water, the normal gas reservoir engineering theory can not interpret the dynamic production data well, which makes the exploitation technical policies can not match the actual conditions of gas reservoirs.Based on the abundant reference surveys and analyses, the paper gives out the gas flow theories and mathematic equations in low permeability gas reservoir and establishes the analyze method of interpreting the modified isochronal tests data in consideration of liquid loading in the bottom hole. Based on the comprehensive analysis of all kinds of productivity-optimization design theories and methods, the paper set up a new productivity optimization design method in which initial pressure gradient and liquid loading in the bottom hole have been taken into account. The application results in Sheng 58 Wang 10-14 Wang 32-19 show that the new productivity optimization design method can determine the optimization production, of the gas well.