A Classification and Description Method for Carbonate Reservoir Mechanical Properties Based on the Hoek-Brown Criterion

Deep carbonate rocks generally belong to dense sedimentary rocks, but the cracks and holes of different scales in the formation will affect the mechanical properties. In the borehole stability analysis of drilling and completion engineering of deep carbonate reservoir, it is necessary to determine the formation mechanical properties through laboratory experiments and use them as basic parameters for calculation. However, limited core experiments are difficult to fully reflect the formation characteristics, and affect the accuracy of the results. Therefore, based on experimental data, Hoek-Brown criterion and well logging data, a comprehensive classification method was established to describe the characteristics of deep carbonate rocks. At first, the cores of a fractured carbonate reservoir with the vertical depth of 7350-7370m were used to carry out indoor unconfined and confined compressive strength experiments, and the core mechanical parameters such as strength, elastic modulus and Poisson's ratio were obtained. Then, based on the experimental results and logging data, the relevant parameters of Hoek-Brown criterion in different section were obtained. Based on the above analysis, a description method for the mechanical properties of carbonates with fractures and holes was established. The analysis results can be used to rock mechanics calculation of deep fractured carbonate rocks.