Fig. 1: Global distribution and drilling depths of representative ultra-deep wells.
From: Ultradeep drilling beyond 10 km revealing new insights into Earth systems and resources
a Global map showing the geographic distribution of selected ultra-deep wells (>7–10 km km) drilled for scientific research and petroleum exploration (locations modified from ref. 2). Colored circles denote different well types: production wells (red), appraisal wells (orange), prospecting wells (blue), and parametric wells (cyan). b Bar chart summarizing the maximum measured drilling depths of the wells shown in (a), with numerical values (in meters) indicated above each bar and colors corresponding to the same well-type classification as in (a).
