Engineered Ultra-Low Invasion Loss Control Solution Allows Circulation, Ensuring Cement Placement and Zonal Isolation in Liner Cementing Jobs and Through Coiled Tubing – Case Studies

Abstract

Abstract The conventional loss cure techniques are largely reactive and include addition of coarse grade particle, fibrous material and other viscous pills that are lost into formation during loss cure attempts. Being highly invasive, these loss cure solutions block pore throats and line producing fractures causing considerable formation damage and loss of net asset value. Moreover, these techniques pose additional challenges while placing thru slim liners and coiled tubing (in rigless applications) due to elevated risk of getting the circulation ports plugged. Moreover, during the era of technological revolution and decarbonization, an effective and efficient solution aids to promote the practices producing low carbon emission. The proactive wellbore shielding loss cure is a particle size distribution-based LCM solution having excellent fluid loss properties and exhibiting low permeability barrier at the fluid-rock interface. The low permeable shielding effect offers less invasion across a broad range of pores (1microns to 4,000microns) and thereby protecting formation from any permanent impairment. The solution covers the wide range applications of loss cure throughout well life ensuring zonal isolation and saving significant rig time. Customized particle size distribution does allow LCM solution to be pumpable thru liner complying the allowable particle sizes (less than 1,000microns) and concentrations (upto 18 lbs/bbl) and for coiled tubing specialized applications with allowable particles size of 100 microns while maintaining rheological properties (Fluid Loss<50 ml/30 min, 5lbs/100ft2>Ty<10lbs/100ft2 & PV<90 cp). This paper demonstrates the working principle and practical applications of engineered solution for loss cure and successfully achieving zonal isolation in 7" liner being placed as pre-cement spacer in naturally fractured formation. The wellbore shielding pre-cement spacer ensured the cement rise above loss point thus achieving zonal isolation in partial to complete losses environment and helps in minimizing formation's impairment. The same approach was adopted to cure losses in rigless with coiled tubing in both carbonate and sandstone reservoirs for well killing and zonal isolation without plugging the CT BHA and circulation ports while complying design requirements.