Innovative Nanotechnology for Enhancing Bridging System Supports Stabilizing Drilling Deep Formations

Abstract Drilling operations of deep oil and gas formations are exceedingly difficult tasks specifically when performed at challenging wells with narrow pressure windows, high overbalance, and cleaning hole difficulties. A flat rheology sealing-based fluid with an optimized bridging system containing a deformable polymer nano in size can overcome the challenges by controlling the equivalent circulation density (ECD), enhancing sealing package and improving hole cleaning efficiency. A flat rheology fluid system provides excellent drilling performance with minimal changes in rheological profile through the temperature changes while drilling. Will discuss in this paper an extensive laboratory work performed to formulate a fluid containing nano-polymers to prove its ability as enhancing sealing particle with different bridging materials sizes, to form a flat rheology system, and to generate a thin stable filter cake. Experiments were performed using dynamic HPHT fluid loss test to simulate filter cake build up, and Permeability Plugging Test (PPT) with different size ceramic disk at different differential pressures <6000 psi, and temperatures close to 320°F. The designed system contains a dry deformable polymer used for sealing shale formations and promoting wellbore stability. The polymer is nano in scale and allows the system to seal micro-pores and micro-fractures in shale formations preventing fluid invasion and reduce fluid loss. The polymer is thermally stable and provides a steady rheological profile. The laboratory results showed 30-50 % decrease in PPT fluid loss values when using the nano-polymer to enhance the sealing capacity of the bridging agents. Successful field stories from rigs executing flat rheology system are also discussed. The enhanced flat fluids at different densities and temperatures were applied in the field, achieving a smooth drilling operation with excellent hole cleaning. The nano-polymer sealing material is an innovative technology that would help to achieve flat rheology fluid while isolating the fracture tip to reduce fracture propagation and permeability of the filter cake while bridging the fracture. The technology effectively reduces the instability associated with pressure sensitive shale and minimize stuck pipe tendencies.