Complex Approach to Drilling Optimization Doubled the Penetration Rates and Eliminated NPT

Abstract

Abstract Horizontal drilling and sidetracking of existing wellbores is one of the main methods of production level increase on brownfields. This paper describes the engineering study on drilling performance enhancement conducted for a group of oilfields in Western Siberia, Russia, where the operator company has just started sidetrack and horizontal drilling campaign. The first several sidetracked wells drilled were characterized by high amounts of non-productive time (NPT) due to downhole tools failures and low penetration rates (ROP). For NPT root cause analysis, drilling surface logging data (including real-time torque and drag analysis) along with downhole measurement while drilling (MWD) vibrations data was analyzed and figured out the failures mechanisms. ROP improvement process included interpretation of LWD and wireline logs and their correlation with bottomhole assembly (BHA) performance via mechanical specific energy (MSE) approach. A number of factors that led to overall unsatisfactory performance on sidetracks were identified. This included wrong bit selection, limited drilling parameters, hole quality problems and cleaning issues and several others. These issues were properly addressed with field-proven drilling optimization process, which resulted in doubling of previously achieved ROP and elimination of NPT. The next sidetrack was drilled with 40% reduction of average rig days per 1000 m. Based on experienced gained, a motorized rotary steerable system (RSS) BHA was selected for the next complex sidetrack well, and provided another record-breaking performance, with another 20% improvement of ROP. The successful techniques are currently being transferred from sidetracks to horizontal sections on new wellbores. The paper represents latest achievements of ongoing drilling optimization process, which allowed the operator company to significantly decrease time and operational costs on drilling operations. The described complex geological and technological approach, along with revised wellbore placement, have led to main project performance indicators increase and next-step completion and production solutions for enhanced hydrocarbons recovery.