Abstract: 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.

Abstract: A method of gravel packing a well. A flow-reducing material is introduced into the annulus between a tubular liner and the well bore so as to collect at the perforations in the well bore and the apertures in the liner. This slows gravel slurry flow to the screen inner annulus and to the perforations to prevent gravel from bridging the annulus at these locations. The material is removed after the risk of bridging has passed. Various flow-reducing materials, such as wax flakes, salt, clay and gel, may be employed. The method is particularly useful in deviated wells.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Petroleum sulfonates are obtained by treating whole crude oil or topped crude oil or mixtures thereof with sulfur trioxide, removing unreacted hydrocarbon, e.g., by addition of water, and neutralizing the sulfonic acids formed with a base, e.g., sodium hydroxide or ammonia. The products have particular utility for the preparation of micellar systems for use in secondary-type petroleum recovery.

Abstract: 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.

Abstract: 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.

Abstract: 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.3 /EDC stream is at least 4:1, respectively.