A method to predict geomechanical properties and model well stability in horizontal boreholes

A numerical study on optimization of multilateral horizontal wellbore patterns for coalbed methane production in Southern Shanxi Province, China

“…The study area was a low permeability reservoir (b1 md), and the authors found that lateral spacing (they modeled multiple single leg wells) was a function of permeability and was especially important in low permeability settings. Subsequent studies by Gentzis and others coupled geomechanical modeling and reservoir simulation to examine influence of wellbore stability (Gentzis et al, 2009a(Gentzis et al, , 2009b. Another study compared several different horizontal multilateral patterns, varying spacing, permeability and lateral length using a reservoir simulator and determined optimum lateral spacing, pattern, and well length based on net present value (Maricic et al, 2008).…”

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.…”

Time delay effect due to pore pressure changes and existence of cleats on borehole stability in coal seam

“…The effect of pore pressure changes during gas production by draining water During gas production by draining water, formation fluid is to flow out persistently and therefore pore pressure near borehole is to reduce gradually. Pore pressure reductions not only influence borehole stability, but also cause local shear failure in coal rock and consequently cause coal fines production and make cleats closed and plugged Gentzis et al, 2009;Gentzis, 2009). Using production data in Zheng Ping 1-1 well, the influences of pore pressure changes on coal rock stability are analyzed qualitatively.…”