×

Enclosed nuclear-magnetism logging tool with compensated coil-isolating system

  • US 4,035,718 A
  • Filed: 08/23/1976
  • Issued: 07/12/1977
  • Est. Priority Date: 08/23/1976
  • Status: Expired due to Term
First Claim
Patent Images

1. A nuclear-magnetism logging tool adapted to be lowered into a borehole penetrating earth formations and comprising:

  • means including electrical coil means operable for momentarily applying an electromagnetic field to such earth formations for temporarily polarizing the nuclei of hydrogenous connate fluids therein and, at a selected time thereafter, detecting at least one measurement signal induced in said coil means in response to the free precession of such nuclei following removal of said polarizing field; and

    means isolating said electrical coil means and including non-magnetic body means defining a fluid-tight space enclosing said electrical coil means and containing a hydrogenous oil having a homogenous suspension of colloidial ferromagnetic particles dispersed therein at a selected concentration sufficient for effecting a controlled decay of noise signals induced in said coil means in response to the free precession of hydrogenous nuclei in said hydrogenous oil following removal of said polarizing field, said controlled decay at a rate sufficient to attenuate said noise signals by said selected time to an amplitude no greater than that of said measurement signal.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×