The wellbore instability problems can rise significantly if the downhole pressure is fluctuated during the tripping operation due to surge and swab effects. Even though the borehole pressure was estimated accurately by geomechanical model, the inappropriate tripping variables could reduce the proposed pressure to hold back mechanically the wellbore wall. Therefore, it is essential to include a safety factor or trip margin to account for the surge and swab pressure in the well construction stage. In this work, Numerous of wellbore instabilities in term of pipe sticking were investigated in a field in southern Iraq that revealed the drilling events experienced while pulling the string out of the hole. Thus, the swabbing effect on the bottom hole pressure was considered depend on the drilling observations and empirical equations. Swapping parameters from twenty-two wells in southern Iraq were implemented to investigate the influence of drilling practices, tools, and rheological properties on the borehole pressure variation. The combination of the drilling fluid density, yield point, plastic viscosity, BHA size, slip to slip time, tripping speed and the depth of investigations was used as input data. The mathematical formulas that account for most sensitive tripping factors were utilized in this research to consider the swabbing effects during the tripping. Afterward, commercial software was used to construct a statically derived swabbing model based on tripping data from offset wells to predict the drilling fluid reduction for particular tripping variables. The software was fed with Mud weight MWT, Flow rate FL, Weight on bit WOB, Total flow Area TFA and Revolution Per Minute RPM to get the drilling density reduction by swabbing effect based on standard linear least square method. Then, suggested tripping variables and the geomechanical model densities were plugs in the swabbing empirical model to mitigate this effect. The swapping data showed the drilling fluid density by swabbing was propositionally increased with the static fluid density and slip to slip time (TT), but the swabbing density is negatively affected by the plastic viscosity, flow rate, and the drill collar outside diameters. However, The yield point does not change the swabbing effect much. The recommended tripping variables were proposed to ensure best drilling practice and problems mitigation for the proposed mud density in the upcoming well. Therefore, tripping margin was also suggested to prevent the wellbore collapse while tripping operation in southern Iraq fields.
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