Exxon Research and Engineering Company

Exxon Chemical Patents, Inc.

Nalco/exxon Energy Chemicals,l.p.

John C Newlove

Lee A McDougall

Robert D Lundberg

Dennis G Peiffer

Lawrence P Sedillo

Evelyn N Drake

Pacifico V Manalastas

Warren A Thaler

Robert C Portnoy

Edward N Kresge

Dennis A Williams

Vijay Swarup

Cruise K Jones

Albert J Geiger

John A Haslegrave

Roger L Horton

Donald N Schulz

Kenneth William Pober

Kissho Kitano

Fati Malekahmadi

John R Walker

David B Acker

John R Stockwell

Daniel Frederick Fehler

Robert E Chumley

Ivian G Keener

Eugen R Werlein

Oil degradable encapsulated breaker particles are used in fracturing operations to break hydro-carbon liquid gelled with salts of alkyl phosphate esters. The preferred breaker chemical is particulate urea coated with sulfonated EPDM.

Use of breaker chemicals in gelled hydrocarbons

The present invention is based on the discovery that viscosification agents selected from sulfonated and neutralized sulfonated ionomers can be readily incorporated into oil-based drilling muds in the form of an oil soluble concentrate containing the polymer. Thus, one embodiment of the present invention provides an additive concentrate for oil-based drilling muds comprising a drilling oil, especially a low toxicity oil, and from about 5 gm to about 20 gm of sulfonated or neutralized sulfonated polymer per 100 gm of oil. Indeed, oil solutions obtained from the sulfonated and neutralized sulfonated polymers used as viscosification agents are readily incorporated into drilling mud formulations.

Drilling mud additives and in adding viscosification additives to

An encapsulated breaker chemical composition used in a fracturing process in an oil or gas stimulation operation which comprises: (a) a breaker chemical; (b) a water soluble sealing layer, such as urea, having a thickness within the range of about 1 to about 30 microns deposited on the surface of said breaker chemical and encapsulating said breaker chemical; and (c) a pinhole free coating of a neutralized sulfonated elastomeric polymer of about 2 to about 80 microns thick deposited onto the surface of the coated breaker chemical, wherein said neutralized sulfonated polymer encapsulates the breaker chemical and is permeable to the breaker chemical.

Composition comprising polymer encapsulant for sealing layer

An encapsulated breaker chemical composition used in a fracturing process in the protection of an oil or gas stimulation operation which comprises: a breaker chemical; and a pinhole free coating of a neutralized sulfonated elastomeric polymer of about 2 to about 80 microns thick deposited onto the surface of the breaker chemical, wherein said neutralized sulfonated polymer encapsulates the breaker chemical, wherein the neutralized sulfonated polymer is permeable to the breaker chemical and the neutralized sulfonated polymer is non-reactive to the breaker chemical.

Composition comprising encapsulated substrate and thermoplastic polymer

An encapsulated breaker chemical composition used in an oil or gas stimulation operation which comprises: a breaker chemical; and a pinhole free coating of an ionically and covalently crosslinked neutralized sulfonated elastomeric polymer of about 2 to about 80 microns thick deposited onto the surface of the breaker chemical, wherein said polymer encapsulates the breaker chemical, wherein the polymer is permeable to the breaker chemical and the polymer is non-reactive to the breaker chemical.

Composition comprising encapsulated substrate with thermoplastic polymer

An encapsulated breaker chemical composition used in an oil or gas stimulation operation which comprises: a breaker chemical; and a pinhole free coating of an ionically and covalently crosslinked neutralized sulfonated elastomeric polyer of about 2 to about 80 microns thick deposited onto the surface of the breaker chemical, wherein said polymer encapsulates the breaker chemical, wherein the polymer is permeable to the breaker chemical and the polymer is non-reactive to the breaker chemical.

Breaker chemical encapsulated with a crosslinked elastomer coating

Encapsulated breaker chemical

Encapsulated breaker chemical with a multi-coat layer urea

A solid polymeric body comprising a polymer matrix containing a substantially water-insoluble reagent leachable into a substantially hydrocarbon liquid environment, the matrix being reagent permeative and the body preferably having a softening point substantially above that of the temperature of the liquid fluid environment in which it is to be employed. The body is useful for the introduction of an additive reagent into a substantially liquid hydrocarbon such as crude and refined oils.

Polymer article of manufacture

Subterranean formations are fractured by use of an aqueous fracturing fluid containing an effective amount of a copolymer of acrylamide and potassium acrylate crosslinked with a titanium or zirconium compounds. The fracturing fluid also contains an oxidative gel breaker. The method is particularly suited for treatment of deep, high temperature formations.

Method of treating subterranean formations using a non-damaging

The present invention relates to sulfonated thermoplastic terpolymers which are terpolymers of p-methyl styrene, styrene and sodium styrene sulfonate wherein these sulfonated terpolymers function as viscosification agents when added to oil-based drilling muds which are the fluids used to maintain pressure, cool drill fits and lift cuttings from the holes in the drilling operation for oil an gas wells. The sulfonated thermoplastic terpolymer of the latex have about 5 to about 100 meq. of sulfonate groups per 100 grams of the sulfonated thermoplastic terpolymer, wherein the sulfonated groups are neutralized with a metallic cation or an amine or ammonium counterion. A polar cosolvent can optionally be added to the mixture of oil drilling mud and sulfonated thermoplastic polymer, wherein the polar cosolvent increases the solubility of the sulfonated thermoplastic terpolymer in the oil drilling and by decreasing the strong ionic interactions between the sulfonate groups of the sulfonated polymer. The drilling muds formed from these lattices of the sulfonated thermoplastic terpolymers exhibits markedly improved low and high temperature rheological properties as compared to drilling muds formed from sulfonated thermoplastic copolymers.

Low and high temperature drilling fluids based on sulfonated terpolymer

An oil-based drilling mud which comprises an organic liquid substantially immiscible in water; about 1 to about 10 parts by weight of water per 100 parts by weight of the organic liquid; about 20 to about 50 lb./bbl. of at least one emulsifier; weighting material necessary to achieve the desired density; and about 0.25 to about 4.0 lb/bbl. of a hydrocarbon soluble polymeric complex formed from a water insoluble anionic polymer and a cationic polymer.

Drilling fluids based on polymer complexes

A method of fracturing a subterranean formation involving the use of crosslinked gels to form a fracture and deposit particulate proppant therein followed by the introduction of dilute aqueous solutions of chlorine dioxide in the propped fracture to degrade the gel.

Hydraulic fracturing with chlorine dioxide cleanup

An oil-based drilling mud which comprises:

Drilling fluids based on hydrocarbon soluble polyampholytes

A process for fracturing a subterranean formation surrounding a gas or oil well which comprises:

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Kingwood, TX, United States of America

John C Newlove