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

Xin Chang,Rui Jian,Ming Tang,Lei Wang,Jun Zhou,Yintong Guo,Yulin Chen,Shiming He

doi:10.3390/en11092414

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.

Highlights

The circulating temperature in the wellbore during the drilling procedure is a matter worth examining
This study was aimed at providing an accurate prediction of temperature distributions that influenced mechanical and hydraulic frictions, such as heat transfer efficiency, drill pipe in wellbores and formations during horizontal well drilling
This study was aimed at providing an accurate prediction of temperature distributions in wellbores and formations during horizontal well drilling

Summary

Introduction

The circulating temperature in the wellbore during the drilling procedure is a matter worth examining. The circulating temperature inevitably affects the properties of operating fluids during the drilling of oil–gas wells, and temperature fluctuations in the wellbore and formations expose the surrounding rocks to the risk of collapse. Temperature impacts the creep rates of soft rock interlayers, such as salt, gypsum, and mudstone. The corrosion of downhole tools and expansion of gas flowing with the drilling fluid are known to be related to the temperature profile. All these aspects mentioned above significantly affect well safety during drilling.

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