Donald Edward Schroeder, JR
Engineers at Gallup St, Littleton, CO

4013125, Mar 22, 1977

Mar 27, 1975

5/562519

Mark A. Plummer - Littleton CO
Donald E. Schroeder - Littleton CO
Wayne O. Roszelle - Littleton CO

Marathon Oil Company - Findlay OH

E21B 4322

166273

Flooding of a subterranean formation with micellar dispersions containing petroleum sulfonates obtained by sulfonating whole or topped crude oil is improved through the use of a micellar dispersion of a predetermined viscosity containing an amount of cosurfactant in excess of that required to cause the micellar dispersion to have the highest viscosity possible for the particular micellar dispersion with the particular cosurfactant used. Preferably, the cosurfactant is an alcohol and the cosurfactant concentration is sufficiently high to control the micellar dispersion to have a predetermined mobility when injected into a hydrocarbon-bearing formation.

4560517, Dec 24, 1985

Aug 22, 1980

6/180250

Donald E. Schroeder - Littleton CO
Mark A. Plummer - Littleton CO
Carle C. Zimmerman - Littleton CO

Marathon Oil Company - Findlay OH

C07C13900, C07C14324

260505R

Petroleum sulfonates are obtained by continuously contacting whole crude oil or topped crude oil with gaseous sulfur trioxide (contains as a diluent sulfur dioxide and light hydrocarbon vapor) in a reaction zone operated at a temperature of 120. degree. -250. degree. F. and a pressure of 3-50 psia. The reaction product is then passed to a vapor-liquid separating stage where a vapor stream is separated and a portion of it is recycled back to the reaction zone; a liquid stream is separated from the separating stage and a portion of it is recycled back to the reaction zone. The remaining portion of the liquid stream is neutralized with a monovalent inorganic base to obtain the petroleum sulfonate. The petroleum sulfonates are particularly useful to recover crude oil from subterranean reservoirs.

3956372, May 11, 1976

Nov 2, 1973

5/412062

John R. Coleman - Robinson IL
Mark A. Plummer - Littleton CO
Carle C. Zimmerman - Littleton CO
Henry J. Pietrzak - Texas City TX
Wayne E. Luetzelschwab - Littleton CO
Kent W. Robinson - Englewood CO
Donald E. Schroeder - Littleton CO

Marathon Oil Company - Findlay OH

C07C14324

260505S

Petroleum sulfonates useful to impart micellar characteristics to mixtures of hydrocarbon and aqueous medium are obtained by reacting a hydrocarbon gas oil feedstock (average molecular weight 250-700; A/AP aliphatic to aromatic proton) ratio 5-50 moles/mole, 30-100% of the feedstock molecules contain aromatic portions and the A/AP ratio of the aromatic portion being about 3-20 moles/mole) with a solution of EDC (ethylene dichloride) containing 0. 1-0. 3 lb. liquid SO. sub. 3 /lb EDC. The SO. sub. 3 concentration is about 0. 1-0. 3 lb. of SO. sub. 3 /lb of gas oil feedstock. Reaction takes place in a back-mix tubular reactor wherein at least about 4 parts of reaction products are recycled per 1 part of reaction products withdrawn and wherein the gas oil feedstock plus recycled reaction products and the SO. sub. 3 /EDC streams entering the reaction zone are in turbulent flow. Velocity ratio of the feedstock plus recycled reaction products stream to the SO. sub.

4932474, Jun 12, 1990

Jul 14, 1988

7/219111

Donald E. Schroeder - Littleton CO
Bradley D. Hutchison - Lafayette LA

Marathon Oil Company - Findlay OH

E21B 4304

166278

A gravel packing process employs a staged screen assembly to prevent sand and other fine particles entrained in the produced hydrocarbon fluids from entering the production tubing and related equipment. The staged screen assembly is provided with a base pipe having rupture disks in its sidewall. The disks rupture at a predetermined pressure differential during gravel packing to enable leakoff of the carrier fluid from the gravel slurry into the base pipe and recirculation of the carrier fluid back to the wellhead, while ensuring complete and uniform gravel packing of the hydrocarbon production interval without substantial bridging or duning.

5062484, Nov 5, 1991

Aug 24, 1990

7/572925

Donald E. Schroeder - Littleton CO
David O. Falk - Denver CO

Marathon Oil Company - Findlay OH

E21B 4304, E21B 4308

166278

A method of gravel packaging a well penetrating and in fluid communication with a subterranean formation or zone by sealing the apertures of a gravel pack liner, except near the bottom of the liner, against entry of slurry fluid. This prevents gravel from clogging the apertures or bridging the annulus between the liner and the well bore. An immobile gel provides the sealing function, and a breaker eventually breaks the gel, thereby permitting removal of the gel and unblocking the apertures. The gel is formed from a suitable liquid composition containing the gel breaker, and may be applied to the liner prior to lowering the liner and wash pipe into the well bore.

3964548, Jun 22, 1976

Mar 27, 1975

5/562520

Donald E. Schroeder - Littleton CO
Mark A. Plummer - Littleton CO
Wayne O. Roszelle - Littleton CO

Marathon Oil Company - Findlay OH

E21B 4322

166273

Improved oil recovery by flooding subterranean formations with micellar dispersions; comprised of hydrocarbon, water, cosurfactant, electrolyte, and petroleum sulfonate obtained by sulfonating whole or topped crude oil; is obtained by incorporating within the micellar dispersion about 1. 5 to about 4. 5 wt. % of active sulfonate groups (e. g. --SO. sub. 3 NH. sub. 4 or --SO. sub. 3 Na) which are attached to the petroleum sulfonate. The micellar dispersions of this invention contain an amount of cosurfactant in excess of the amount required to produce a viscosity maximum with the particular micellar dispersion.

4510397, Apr 9, 1985

Jul 20, 1983

6/515407

Donald E. Schroeder - Littleton CO

Marathon Oil Company - Findlay OH

F03B 1300, H02K 718

290 43

Flow control of diluted polymer solutions is effected by utilizing positive-displacement flow devices such as gear pumps to withdraw flow energy in the form of shaft work. Control is obtained by varying the nature and amount of shaft work withdrawn, such as by operation of an electrical generating system, and the work so created may be used to provide operating power to a control system.

5127474, Jul 7, 1992

Dec 14, 1990

7/627180

Donald E. Schroeder - Littleton CO
Brian A. Butler - Lafayette LA

Marathon Oil Company - Findlay OH

E21B 4304

155278

Method and means for preventing fluidization or mobilization of a gravel pack in a fluid producing well as a result of increased fluid pressure caused by a well shut-in or other pressure surge. A pressure relief valve in the form of a check valve is provided in a tubing string below a packer surrounding the string and above the top of the gravel pack. The check valve is held in closed position by a biasing force, such as a spring, which is less than the pressure which will cause mobilization or fluidization of the gravel pack. A pressure surge such as a well shut-in or flow rate decrease increases tubing pressure which causes the check valve to open, thereby relieving the pressure in the gravel pack to a point below the critical level.

6253851, Jul 3, 2001

Sep 20, 1999

9/399135

Donald E. Schroeder - Littleton CO
Philip H. Winterfeld - Englewood CO

Marathon Oil Company - Findlay OH

E21B 4304, E21B 43267

166278

This invention relates to a method of completing a well that penetrates a subterranean formation and more particularly to a method for screen placement during proppant packing of formation perforations or fractures created by hydraulic fracturing techniques. The top of the screen is placed at a sufficient distance below the top of the perforations such that the frac pack pumping rate does not bridge off at the top of the screen when the frac pack is being pumped.

4464509, Aug 7, 1984

Jul 20, 1983

6/515402

Donald E. Schroeder - Littleton CO

Marathon Oil Company - Findlay OH

C08C 1900

525 53

Apparatus and method of preparing a partially hydrolyzed polymer solution, especially a partially hydrolyzed polyacrylamide solution, for use in secondary and tertiary oil recovery operations which involves the in-line introduction of a relatively concentrated solution of a hydrolyzing agent into a polymer stream having a relatively high concentration of the polymer, and thereafter intimately mixing, under heat, the polymer stream and the hydrolyzing agent while controlling the flow rate of the reaction mixture. The reaction mixture is then held in a post hydrolysis tank where the reaction is allowed to go to completion.