Application of elemental logging technology in geological steering of Jinzhou 25-1 Oilfield

The main development layers of Jinzhou 25-1 Oilfield in Bohai Sea are located beneath thick-layer mudstone sections of Dongying Formation. Due to restrictions from fishing zones and military areas, extended-reach wells are often used for development. However, the lack of distinct characteristics in the logging curves of the thick mudstone section makes challenges for stratigraphic correlation, affecting the success rate of landing, coring, and other operations. To improve the accuracy of geological steering, a method for detailed stratigraphic correlation based on elemental logging technology was explored. This method involves reconstructing and subdividing thick-layer mudstone section using elemental logging data, analyzing elemental content characteristics to identify sedimentary facies and establish marker beds, and selecting key points for geological steering trajectories within each sub-layers. This approach forms a geological steering technology suitable for detailed stratigraphic correlation in thick-layer mudstone sections. The technology has successfully achieved detailed stratigraphic correlation in the thick mudstone sections of Jinzhou 25-1 Oilfield, significantly enhancing inter-well correlation accuracy, oil-bearing reservoir identification, and geological steering precision, ensuring the successful completion of geological and engineering objectives. This research expands the application scope of elemental logging technology, reflects the integration of geology and engineering. It provides effective technical support for extended-reach well development under complex geological conditions, demonstrating significant practical value and potential for widespread adoption.