Optimum directional well path design considering collapse and fracture pressures

Abstract

Well path optimisation is often done based on the wellbore stability where the production related concerns are ignored. In fact, many of the studies carried out in the past have not included hydraulic fractures into their calculations. In fact, an optimum path for wellbore should not only provide the maximum stability during drilling but also offer a relatively low pressure to fracture the formation in the production stage. In this study, attempts are made to provide a methodology to determine an optimum well path for drilling, hydraulic fracturing and production stage using wellbore stability analysis in different stress regimes. An analytical model was proposed and used to determine the collapse pressure and fracture gradient during drilling and hydraulic fracturing at various azimuths and inclinations. The results obtained revealed that the well path does not change in a normal faulting regime during production. However, the azimuth and inclination of wells may need to be changed in the strike-slip and reverse fault regimes for a better drilling and fracturing. It was also found that deviated wells can be a better option in normal and strike-slip stress regimes, but further studies might be needed to confirm these findings.