“…The authors separated the pressure field around the well into four parts according to the cause of pressure fields, maximum horizontal principal stress σ H1 , minimum horizontal principal stress σ H2 , vertical stress σ v , and wellbore pressure p wf Fig. (1). To make it easier to calculate, they changed the coordinates into rectangular coordinates whose Z axis coincides with well axis, so that the original σ H1 , σ H2 and σ v will be changed into σ xx , σ yy , σ zz , τ xy , τ xz , and τ yz under new coordinates Fig.…”