The Earth Stress Calculation Using Well Logging Data And Its Applied Research In Piedmont Structure

The earth stress calculation and sidewall stability analysis using well logging data in Piedmont Structure have the very important meaning to oil/gas exploratory development. Dynamic and static elastic parameters of rocks samples are measured synchronously under triaxial stresses. I establish the linear regression relationship between dynamic and static elastic parameters. The study results provide an experimental basis for the application of sonic properties of rock in the petroleum engineering. The parameters required for earth stress calculation are determined, such as the rock mechanics and the inherent rock strength using well log data and available results. Using Huang'earth stress model is to quickly get the stress profile spreading along the depth. The calculated stress coincides with the result of the acoustic emission experiment. In order to improving and perfecting the precision of the earth stress, I draw lessons from predecessors in the pore pressure and tectonic stress coefficient. The horizontal stress direction of the target zone in the DiNa gas filed is determined by means if borehole breakout data, drilling induced fracture and DSI fast shear azimuth. Being summarized the types and the reasons of the hole instability, I analyze the three kind of strength criterion. On the basis of rock mechanics and wellbore stability analysis, breakdown pressure, caving pressure and drilling fluid density can be obtained, which will act as references for drilling design to guide safe drilling.