MAGNETIC GRADIENT DRILLING

Aspects of magnetic gradient drilling are described. In one embodiment, a system includes a drill pipe, drilling fluid, and a magnetic assembly tool connected to or integrated with the drill pipe. Among other elements, the magnetic assembly tool can include a magnetic field generator configured to generate a magnetic field and create an additional pressure drop in the drilling fluid outside the drill pipe, and a magnetic shielding material configured to shield the magnetic field from inside the drill pipe. 1. A system , comprising:a drill pipe; and a magnetic field generator configured to generate a magnetic field and create an upstream pressure drop in magnetorheological fluid outside the drill pipe; and', 'a magnetic shielding material configured to shield the magnetic field from the magnetorheological fluid inside the drill pipe., 'a magnetic assembly tool connected to or integrated with the drill pipe, the magnetic assembly tool comprising2. The system of claim 1 , wherein the magnetorheological fluid flows downstream inside the drill pipe and flows upstream outside the drill pipe.3. The system of claim 1 , wherein the magnetic field generator is configured to selectively generate the magnetic field based on an electric current or axial force applied to the drill pipe.4. The system of claim 1 , wherein the magnetic field generator comprises at least one of a magnetostrictive material claim 1 , a permanent magnet claim 1 , or an electromagnet.5. The system of claim 1 , wherein the magnetic field generator comprises a magnetostrictive material claim 1 , and the magnetic assembly tool further comprises a sealing mechanism configured to direct axial force applied to the drill pipe into the magnetostrictive material to generate or modify the magnetic field.6. The system of claim 1 , wherein the magnetorheological fluid coagulates in the magnetic field outside the drill pipe to create a choke point in an annulus outside the drill pipe.7. The system of claim 6 , ...