The development of geostress profile has opened a new field for log data application.According to the analysis of the geostress field of 4 wells in XL Gasfield in West Sichuan

the rock dynamic parameters

the 3-D principal stress

the direction of horizontal stress field

the common engineering pressure and sand producing index of the reservoir in Shaximaio Formation of XL Gasfield in West Sichuan have following characters:1.the development degree of porosity and fractures can effect reservoir dynamic property;2.3-D principal stress could usually satisfy the following relational expression:σ

H

>

σ

V

>

σ

h

the horizontal stress and breakdown pressure of fracture developed horizon are usually lower than that of country rock

but the slump pressure is higher than that of the country rock;3.horizontal principal stress basically coincides with horizontal principal stress of regional tectonics in West Sichuan excepting particular horizons;4.sand producing index is high and there is no sand produced.