Encapsulated oil absorbent polymers as lost circulation additives for oil based drilling fluids

Patent · Tue Nov 03 00:00:00 EST 1987

OSTI ID:5821082

Delhommer, H J; Walker, C O

A drilling fluid additive for reducing lost circulation of oil based drilling fluids in a borehole penetrating an underground formation is described comprising: an oil absorbent polymer which expands upon absorbing oil. The oil absorbent polymer is a cross-linked linear addition polymer containing repeating units of vinylbenzyl alcohol and at least one other alpha, beta-monoethylenically unsaturated monomer different from vinylbenzyl alcohol, wherein the vinylbenzyl alcohol units comprise about 0.5% to about 20% by weight of the linear polymer. A method of reducing lost circulation of oil based drilling fluids in a borehole penetrating an underground formation, is described comprising: adding an oil absorbent polymer which expands upon absorbing oil to a slug of drilling fluid, the polymer encapsulated with a clay; spotting the slug of drilling fluid and polymer within a lost circulation zone; shearing the clay encapsulation with the circulating jets of the drill bit, permitting the encapsulated polymer to be released from its clay encapsulation and absorb oil and expand to close off the lost circulation zone; and resuming circulation to clear the borehole of undesired compounds.

• Assignee: Texaco Inc., White Plains, NY
• Patent Number(s): US 4704213
• OSTI ID: 5821082
• Resource Relation: Patent File Date: Filed date 28 May 1985
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
DRILLING FLUIDS
ADDITIVES
ADSORBENTS
CHEMICAL COMPOSITION
ADSORPTION
CLAYS
CROSS-LINKING
CUTTINGS REMOVAL
NATURAL GAS WELLS
OIL WELLS
PETROLEUM
POLYMERS
CHEMICAL REACTIONS
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUELS
POLYMERIZATION
REMOVAL
SORPTION
WELLS
020300* - Petroleum- Drilling & Production
030300 - Natural Gas- Drilling
Production
& Processing