Research on Calculation Methods for Rock Mechanical Parameters Based on Digital Drilling Cuttings

Horizontal and directional wells, along with hydraulic fracturing are important techniques in unconventional oil and gas exploration and development. The rock mechanics parameters of formation rocks are crucial for evaluating reservoir engineering quality and well construction design. Currently, the main methods for calculating rock mechanics involve the direct core rock mechanical experiments and indirect well logging data evaluation; however, these methods are both time-consuming and expensive. Digital drilling cuttings (DDC) have become an alternative means for rapid evaluation of rock mechanics parameters at drilling sites. This paper presents a methodology and workflow for computing rock mechanics parameters using drilling cuttings mineral data. Initially, drilling cuttings undergo preprocessing and sample preparation. Subsequently, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS) is employed to characterize particle morphology, surface porosity, micro-fracture development, and mineral composition. Based on the mineralogical and pore-fracture data, equivalent static rock mechanics parameters are calculated using rock physics modeling. These static parameters are then converted to dynamic parameters through linear regression analysis. Comparative analysis with conventional well-log evaluation results demonstrates that digital drilling cuttings technology can effectively derive key parameters—including elastic moduli, failure index, and brittleness index—providing critical insights for unconventional resource exploration and development. The limitations of the current models are also analyzed and the future research directions are introduced.