Heat Transfer Behaviors in Horizontal Wells Considering the Effects of Drill Pipe Rotation, and Hydraulic and Mechanical Frictions during Drilling Procedures

Abstract

Horizontal wells are increasingly being utilized in the exploration and development of oil and gas resources. However, the high temperature that occurs during drilling processes leads to a number of problems, such as the deterioration of drilling fluid properties and borehole instability. Therefore, the insight into heat transfer behaviors in horizontal wells is certainly advantageous. This study presents an integrated numerical model for predicting the temperature distribution during horizontal wells drilling considering the effects of drill pipe rotations, and hydraulic (i.e., circulating pressure losses) and mechanical frictions. A full implicit finite difference method was applied to solve this model. The results revealed that the mechanical frictions affect more on wellbore temperature variation than the effects of heat transfer intensification and circulating pressure losses; Moreover, the drilling fluid temperature was found higher than the stratum temperature at horizontal section, the temperature difference at the bottom hole reached up to 16 °C if pressure drops, heat transfer strengthened by rotations and mechanical frictions were all taken into account. This research could be utilized as a theoretical reference for predicting temperature distributions and estimating risks in horizontal wells drilling.

Solution and Analysis of Wellbore Temperature and Pressure Field Coupling Model under Lost Circulation

“…Although the research on wellbore heat transfer of drilling fluid under no-loss circulation conditions has become mature, there are few studies on variable mass heat transfer of annulus fluid under loss circulation. − In 2017, Chen et al established the first variable mass heat transfer model in the wellbore under the lost circulation condition and also proposed a method to judge the position of the loss zone according to the temperature gradient curve. However, due to its failure to fully consider the heat source generated in the drilling process and the influence of the casing program on the wellbore temperature distribution, the model has a large error in the drilling process of deep and ultradeep wells.…”

Modelling of the cooling effect enhancement in drilling fluid using nanotechnology

“…In the model, the initial temperatures of the drilling fluid and the formation are 126 o C and 50 o C, respectively. In the drilling process, the extra heat generated by friction is considered to be 16 o K according to Xiu Chang et al 10 . Changes in thermal conductivity of the drilling fluid were modelled using results from literature review.…”