Table 2_Present-day thermal regime of the Xihu Sag, East China Sea Shelf Basin: constraints from an updated well database and logging-derived thermal conductivity.xlsx

The East China Sea Shelf Basin, situated at the convergent boundary of multiple plates, represents a unique tectonic setting where Cenozoic rifting has produced an anomalously high thermal state that remains poorly documented. This study presents a logging-based workflow to predict thermal conductivity and compiles an updated geothermal database for the Xihu Sag of the East China Sea Shelf Basin.</p>Methods<p>We compile temperature measurements from 102 wells and thermal conductivity data from 21 new core samples, supplemented by logging-predicted thermal conductivity from 62 wells using a back-propagation (BP) neural network.

Bottom-hole temperatures (BHTs) were corrected using the Waples method and validated against drill-stem test (DST) temperatures.</p>Results<p>Geothermal gradients range from 25.7 °C to 39.8 °C/km (mean 34.0 °C ± 3.5 °C/km), increasing eastward from the Western Slope Belt (31.4 °C/km) to the Central Anticline Belt (38.0 °C/km). Heat flow values range from 44 to 82 mW/m² (mean 63 ± 8 mW/m²), reaching 73 mW/m² in the eastern anticline zone.</p>Discussion<p>The observed eastward-increasing thermal gradient is dually controlled by deep lithospheric thinning and basement morphology-induced thermal refraction.