Journal Article

Evaluating the Anisotropy of Drilling Mechanical Characteristics of Rock in the Process of Digital Drilling

He, Mingming, Li, Ning, Ma, Chunchi, Wang, Haoteng, Zhang, Zhiqiang

2023

Overview

The engineering behaviour of rock is strongly associated with the anisotropy, which exists at different scales for construction safety and evaluation of rock properties. It is also well known that the anisotropy of the drilling mechanical characteristics in the rock cutting process has an essential effect on the drilling efficiency and cost. For this purpose, an effort was made to characterize the anisotropy of the drilling mechanical characteristics of rocks in the rock drilling process. The drilling strength and specific energy at the cutting point are considered to characterize the drilling process in three different directions according to the drilling response model. A drilling characteristic-based index is proposed to evaluate the anisotropy of rock. Drilling tests were conducted in three directions for six types of rock to study the anisotropy variation along the borehole depth. The anisotropy evolution result along the borehole suggested that this critical point is identified as the cutting point, dividing the drilling process into two stages of cutting and frictional contact. The cutting point also shows anisotropic features. The anisotropic ranking of tested rocks was obtained. Based on how the drilling parameters depend on the unconfined compressive strength, the reliability of the proposed anisotropy index is examined by comparison with the strength anisotropy index. The comparative result demonstrates that the proposed method can provide a reliable determination for rock anisotropy by using the drilling strength. The work performed in this paper provides a very useful approach for evaluating the anisotropy of rock and provides a good understanding of the drilling mechanical characteristics in rock drilling.HighlightsThe anisotropy of the drilling mechanical characteristics of rocks is characterized in the rock drilling process.The drilling strength and specific energy at the cutting point are considered to characterize the drilling process in three different directions.A drilling characteristic-based index is proposed to evaluate the anisotropy of rock.Drilling tests are conducted in three directions for six types of rock to study the anisotropy variation along the borehole depth.

• Publisher: Springer Nature B.V
• Subject: Anisotropy / Boreholes / Compressive strength / Construction accidents & safety / Construction industry / Critical point / Cutting / Drilling / Evaluation / Mechanical properties / Occupational safety / Rock / Rock properties / Rocks / Specific energy