Pressure is a significant factor affecting moduli and velocities of shale gas or oil reservoir. One novel iterative rock physical model building approach of shale is initially proposed in this study to analyze the effect of the pressure on shale by introducing the pore space stiffness theory into the procedure of model building. Pore space stiffness theory holds that like the solid matrix of rocks, pores has its own stiffness which is related to the effective pressure. We implement plenty of numerical tests to analyze how the pressure affects the shale by rock physical modelling, and find out the most contributive factor to the moduli and velocities in shale. The result shows that bulk modulus, shear modulus and elastic wave velocities increase significantly with the increase of effective pressure before the effective pressure achieving a critical value, and tend to be constant when the effective pressure goes beyond the critical pressure. By comparing the effect of pressure, porosity, crack content, water saturation and minerals, we found that the most contributive mineral is clay, and porosity has the greatest impact on moduli and velocities of shale among other factors. In shale reservoirs with low porosity (lower than 10%), the effect of pressure is not as obvious as other factors, because pores occupies a relatively small percentage of the rock.
Presentation Date: Tuesday, September 17, 2019
Session Start Time: 1:50 PM
Presentation Start Time: 2:40 PM
Location: Poster Station 1
Presentation Type: Poster
