The reef gas reservoir of Changxing Formation in Yuanba Gas Field is an ultra-deep gas reservoir with bottom water and high sulfur content

and it is in the early stage of stable production. The dynamic monitoring shows that the risk of water invasion in the development of gas reservoir is high

which brings great challenges to the dynamic analysis of gas reservoir. Combined with the actual geological characteristics and production status of Yuanba Gas Field

the daily production and pressure data are fully used to carry out the application analysis of the yield instability analysis method （Agarwal Gardner

Blasingame

NPI

etc.）. The results show that this method can be applied to analyze the reservoir dynamic parameters

gas well dynamic productivity

dynamic reserves and water invasion identification of the gas reservoir in Changxing Formation Yuanba Gas Field. The obtained results are highly reliable

which is helpful to deepen the understanding of the geological characteristics of gas reservoirs

solve the production problems

and further guide the dynamic analysis of gas reservoirs.