Evaluation of drilling model of deep extended reach well in Jinzhou based on learning curve.

With the continuous increase in the drilling operations of deep high-displacement wells in the Bohai Oilfield, higher demands are being placed on project management in petroleum engineering. It is imperative for us to have a more comprehensive understanding of project management and conduct more extensive research on deep high-displacement wells. We take the Jinzhou Block in the Bohai Oilfield as an example to study the influencing factors on the drilling cycle of deep high-displacement wells. Furthermore, we have analyzed the application effects of different drilling techniques based on learning curves, and achieved valuable insights. (1) In the drilling process of high-displacement wells in Jinzhou, there is a significant positive correlation between drilling depth and drilling operation cycle. The thickness of bottom gravelly strata shows a positive correlation with the drilling operation cycle. The drilling fluid density exhibits a negative correlation with the drilling operation cycle, while the density window for fluid loss during drilling shows a positive correlation with the drilling operation cycle. (2) Evaluating drilling operation performance based on learning curves helps in the progress management and cost control of high-displacement well projects. (3) In the 16-inch wellbore, the utilization of large borehole drilling technology resulted in an average reduction of 4.57% in the drilling cycle. In the 12-1/4-inch wellbore, the implementation of synthetic-based drilling fluid technology led to an average reduction of 7.55% in the drilling cycle. Furthermore, the application of continuous circulation technology in the 8-1/2-inch wellbore effectively stabilizes the Equivalent Circulating Density (ECD), maintains bottom hole stability, and achieves zero drilling fluid losses. Through the study of drilling patterns for deep high-displacement wells in Jinzhou based on learning curves, we have gradually developed a comprehensive technical system and mature operational mode for such wells. With the reliance on this technical system and operational mode, we are able to further reduce the drilling cycle of deep high-displacement wells and enhance operational efficiency.