Geohistory Analysis of Block 14, Say’un–Masilah Basin, Yemen.

This study presents a comprehensive geohistory analysis of Block 14 (Masila Block), Say’un–Masilah Basin, eastern Yemen, based on one-dimensional (1D) Airy backstripping of stratigraphic data from 22 wells across the Cammal, Sunah, and Tawilah fields. Eleven formations spanning approximately 161 million years (Ma), from the Middle Jurassic Kuhlan Formation (161.2 Ma) to the Paleogene Umm Er Radhuma Formation (56 Ma), were analyzed. For each formation and well, present day and initial porosity, decompacted sediment thicknesses, total and tectonic subsidence and their rates, and sedimentation rates were quantified. Decompacted thickness consistently exceeds present-day values across all formations, with the greatest compaction effect recorded in the Shuqra Formation at Sunah-01 (∼ 60 mlost to compaction). Total subsidence ranges from 28 m (Kuhlan Formation) to 943 m (Harshiyat Formation). Tectonic subsidence was lowest during pre-rift Kuhlan deposition (∼ 25 m average), increased during syn-rift Naifa deposition (∼ 162 m average), and peaked during Harshiyat deposition (∼ 665 m; 5.33 cm/1,000 yr). The Mukalla Formation records the highest sedimentation rate (14.5 cm/1,000 yr average). Sunah-01, located in the northeastern part of the study area, records the highest cumu- lative total subsidence (3779 m) and tectonic subsidence (2970 m), corresponding to the thickest sedimentary succession. Tawilah-99, in the southeastern part of the study area, records the lowest cumulative values (total: 2479 m; tectonic: 1813 m), corresponding to the thinnest succession. These results provide a quantitative geohistory framework for Block 14 and a basis for future petroleum system modeling within the Say’un–Masilah Basin.