Gravel packing methods in long blank sections with near vertical regime in openhole

Abstract

Gravel packing is a well-known method in sand control where stabilizing the formation with gravel prevents the production of formation sand. Longer and more complex completion operations are making the business of completing wells continually changing with new challenges, new technology and new methods. The purpose of this thesis is to discuss the gravel placement in nearly vertical openhole systems with blank pipe sections between the screens. In vertical openhole completions with long blank pipe sections slurry and gravel settling regimes will occur differently compared to a conventional gravel pack operation without blank pipe sections. The reason for this is when a lower screen section is packed with gravel and the overlying section is with blank pipe, the carrier fluid can no longer flow through the lower screen. The gravel in the blank pipe sections is mainly settling due to gravitational forces and therefore displaces the carrier fluid, which flows upwards to the upper screen section. By simulating gravel pack operations with blank pipe sections in Halliburton’s laboratory scale model in Tananger it has recently been shown (with continuous pumping) that with a higher inclination on the well (less vertical), a better packing is achieved in the blank pipe section; a higher gravel pack efficiency is achieved.

By analyzing and calculating theoretically how the gravel settles with regards to physical laws in fluid dynamics will give a better view on how to optimize the packing of gravel in the blank pipe sections in nearly vertical wells. How to optimize the packing in these blank pipe sections without the use of extensive expensive rig-time was one of several challenges that had to be taken into account during the work with this thesis. The combination of solids and fluid in one flow resulted in complex calculations, and certain parameters were therefore predetermined and assumptions like fluid loss and particle interaction were set to zero to simplify the calculations. The parameters in this thesis take the basis in ta field located in the Norwegian sector.