Magnetic shielding and magnetically shielded borehole core drilling

Patent · Tue Dec 02 00:00:00 EST 1986

OSTI ID:7229851

Henry, W E

A magnetic shielding member is described comprising: a first hollow portion which includes a wall having a first opening therethrough, the wall having an exterior surface. The first portion is composed of a ferromagnetic material characterized by an initial magnetic permeability of at least about 10,000 gauss/oersted; and a second hollow portion, having an axis, of ferromagnetic material also characterized by an initial permeability of at least about 10,000 gauss/oersted. The second portion has a first end at which the second portion meets the first portion at the exterior surface. The second portion also has a second open end generally opposite the first end and a sidewall which extends between the ends and which extends outwardly from the exterior surface so as to generally surround the first opening and so as to generally taper toward the axis from the first end to the second open end. At least a portion of the second portion sidewall is flared such that a first acute angle defined between the axis and the sidewall near the first end is greater than a second acute angle defined between the axis and the sidewall near the second end. The difference between the first acute angle and the second acute angle is about 10/sup 0/, and the sidewall has an interior surface which defines an interior space therein which communicates with the first opening.

• Assignee: Phillips Petroleum Co., Bartlesville, OK
• Patent Number(s): US 4625573
• OSTI ID: 7229851
• Resource Relation: Patent File Date: Filed date 23 May 1985
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
42 ENGINEERING
CORING EQUIPMENT
MAGNETIC SHIELDING
WELL DRILLING
BOREHOLES
FERROMAGNETIC MATERIALS
INCIDENCE ANGLE
MAGNETIC SUSCEPTIBILITY
NATURAL GAS WELLS
OIL WELLS
SPACE DEPENDENCE
CAVITIES
DRILLING
DRILLING EQUIPMENT
EQUIPMENT
MAGNETIC MATERIALS
MAGNETIC PROPERTIES
MATERIALS
PHYSICAL PROPERTIES
SHIELDING
WELLS
020300* - Petroleum- Drilling & Production
030300 - Natural Gas- Drilling
Production
& Processing
420206 - Engineering- Mining & Drilling Equipment & Facilities- (1980-1989)