Transient temperature prediction models of wellbore and formation in well-kick condition during circulation stage.

Abstract In the exploration and development of deep reservoir resources, well kick often occurs during drilling. The occurrence of well kick can change the flowing state and the various properties of the drilling fluid, which can have a very important impact on the wellbore temperature distribution. Based on the actual situation in the drilling process, the wellbore and formation heat transfer model in the case of normal circulation and in the case of well kick in the open-hole formation was established. The model was discretized by using the finite volume method and solved with under-relaxation iterative method. By comparing with previous research results, the validity of the model was established. Compared with the condition of normal circulation, the occurrence of well kick significantly changes the wellbore temperature distribution and has an important influence on the temperature difference profile and formation radial temperature distribution. Sensitivity factors that affected the wellbore temperature distribution were analyzed. Based on the difference in wellbore temperature distribution under normal circulation conditions and well kick conditions, this paper proposes a new method to detect the occurrence of well kick by monitoring the annulus temperature change. The new method can provide guidance for the well control operations and drilling operations. Highlights • Transient temperature model of wellbore in well-kick condition was established. • Temperature distribution of wellbore and formation was analyzed. • Sensitivity factors affected the wellbore temperature distribution were analyzed. • A new method to detect the occurrence of well-kick was proposed. [ABSTRACT FROM AUTHOR]