Effects of fluid seepage on wellbore stability of horizontal wells drilled underbalanced

Contamination of cement slurries with diesel-based drilling fluids in a shale gas well

“…Most of the work done on this topic either by researching effectively spacer fluid to prevent contamination or adding appropriate additives in cement slurry and drilling fluid to improve the compatibility between cement slurry and mud (Brothers and deBlanc, 1989;Skalle et al, 1991;Harder et al, 1993a,b;Fleming et al, 1998;Salehi et al, 2009;Budiawan et al, 2014;Shahvali et al, 2014;He et al, 2014;Farahani et al, 2014;Velayati et al, 2015;Teodoriu and Asamba, 2015;Ariyanti et al, 2015). However, OBMs are difficult to clear because of their strong adhesion to the casing and well.…”

Strength varying laws of rock soaked with supercritical CO2drilling fluid and the prediction of safe mud weight window

“…The effect of soaking differs depending on the medium. Thus, the importance of the fluid soaking effect cannot be overemphasized in designing the drilling fluid and conducting the wellbore stability analysis . Wellbore instability is likely to occur in part of the dangerous sections of the wellbore if engineers do not consider the fluid soaking effect and use the rock parameters measured from conventional coring for the design of the drilling fluid.…”

Mechanical Behavior and Permeability Evolution of Reconstituted Coal Samples under Various Unloading Confining Pressures—Implications for Wellbore Stability Analysis

“…Thus, unloading confining pressure (UCP) is a very common phenomenon during UBD. It suspected that an increase of deviatoric stress caused by the decrease of the strength of the coal wellbore due to the UCP squeezes the drilling fluid [30], since the decrease of BHP is similar to UCP [31]. The strength parameters using the CTC test are overestimated due to not considering the coal damage from UCP.…”