Influence of drill-string lateral collision on wellbore stability of a horizontal well

Abstract

A finite element model of wellbore stability was proposed for a horizontal well, and drill-string friction and lateral collision in the process of rotary motion were taken into account. An unconfined compression test was used for model validation, the normalized yielded zone area (NYZA) was employed to analyze wellbore stability, and the influence of a lateral collision on wellbore stability was simulated. The results indicated that the stress-strain curve of numerical simulation consists with unconfined compression test, and the maximum relative error is <2.2%. The evolution of NYZA can be divided into three typical stages: stage I (static balance), stage II (dynamic growth), and stage III (dynamic balance). Both normal and shear stresses reach to the peak value in stage II, while they always fluctuate in a relatively small range in stage III, so that the wellbore stability mainly affected by the first collision of drill-string. Both lateral acceleration and friction effects have significant impact on wellbore stability. The initial collision position and the size of drilling tool have a certain influence on wellbore stability, while the revolving speed of drill-string almost has no impact. The present paper has guiding significance for wellbore collapse prevention and drilling parameter optimization.

Minimizing Drill-String-Induced Wellbore Instability

“…Based on available literature (Liao et al 2012;Ma et al 2022), we conclude that friction between the drill string and the formation plays a vital role in dictating the drillstring vibration and wellbore stability. The rougher the formation, the more prone the rock is to be damaged by drill-string oscillations.…”

“…Various researchers have tried to quantify the effect of different drilling parameters on the intensity and severity of drillstring vibrations in wellbores (Jafari et al 2012;Liao et al 2012;Ma et al 2022). In this line, several drilling parameters such as WOB, RPM, and mud and formation properties such as friction, formation strength and natural fractures play significant roles.…”

“…Apart from these parameters, the impact velocity at which the drillstring collides with the formation is crucial. When the impact force exceeds a formation's specific strength threshold value, appreciable formation damage can ensue (Huang et al 2021;Ma et al 2022). This happens because crack propagation in rock is a time-dependent process (Fig.…”

“…In contrast, in the opposite scenario, intense lateral vibration can also lead to axial and torsional vibrations. Please note that lateral vibrations in vertical wellbores are much stronger than torsional vibrations whereas axial vibrations become critical when using axial vibration-generating instruments downhole or drilling hard formations.Parameters controlling drillstring vibrationVarious researchers have tried to quantify the effect of different drilling parameters on the intensity and severity of drillstring vibrations in wellbores(Jafari et al 2012;Liao et al 2012;Ma et al 2022). In this line, several drilling parameters such as WOB, RPM, and mud and formation properties such as friction, formation strength and natural fractures play significant roles.…”

Analytical Model of Wellbore Stability Analysis of Inclined Well Based on the Advantageous Synergy among the Five Strength Criteria

“…Thus, the WSA is vital for designing a proper mud weight to maintain wellbore stability. To accurately predict the collapse and fracture pressures, various analytical and numerical models have been proposed and employed for WSA [8,15,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], and most of them are still elastic methods. The most common elastic analysis process of wellbore stability includes two major steps [8]: (1) determine the wellbore stress components using analytical solutions of elastic stress distribution and (2) estimate the wellbore failure by selecting a proper strength criterion.…”