Mechanical properties of reservoir rocks in Bornu basin Nigeria from sonic derived elastic constants

Abstract

Knowledge of geo-mechanical competency of a reservoir rock is necessary before the hydrocarbon in such a formation can be exploited. Such useful information can be obtained from elastic parameters determined from exploratory well logs. This study analytically predicted the S-wave and P-wave velocities from sonic logs of ten exploratory wells from Chad Basin Nigeria. With the determined rock properties, the geo-mechanical constants were computed, and the values used for further interpretation of formation substructure. The computed parameters are useful in well planning, risks assessments and safety optimization. The results of the study show that the Bulk modulus and the ratio of Shear modulus to compressibility are relatively low but falls within the acceptable range for reservoir production. The average Bulk modulus is lower than the threshold value of 2.07 x 1010 Pa in which fluids can be safely produced at any rate.

Keyword: Elastic constants, Modulus, Mechanical competency, reservoir, Bornu Basin.