Controlled fracturing in geologic formations is carried out by a system for generating fractures. The system comprises: a plurality of electrodes for placing in boreholes in a formation with one electrode per borehole, for the plurality of electrodes to define a fracture pattern for the geologic formation; a first electrical system for delivering a sufficient amount of energy to the electrodes to generate a conductive channel between the pair of electrodes with the conductivity in the channel has a ratio of final to initial channel conductivity of 10:1 to 50,000:1, wherein the sufficient amount of energy is selected from electromagnetic conduction, radiant energy and combinations thereof; and a second electrical system for generating electrical impulses with a voltage output ranging from 100-2000 kV, with the pulses having a rise time ranging from 0.05-500 microseconds and a half-value time of 50-5000 microseconds.

Method of simultaneous introducing of two or more than two chemical substances and/or water into a subterraneous hydrocarbon formation and/or control of the rate of chemical reactions of these substances, and a device for implementation of this method This invention relates to the method of simultaneous introducing of two or more than two chemical substances and/or water into a subterraneous hydrocarbon formation and/or control of rate of chemical reactions of these substances and/or water by introducing their controlled amount into a subterraneous formation containing liquid and/or gaseous hydrocarbons, particularly crude oil, shale gas or natural, below a dedicated packer for exploration and production of these hydrocarbons and simultaneous inserting of a dedicated data cable (3) for interconnection of the measuring and/or regulating components in the wellbore, where the said chemical substances and/or water are supplied into the wellbore at controlled rate through the free casing (5) by means of at least three mutually separated flexible tubing (2a,b) (flexible injection lines) or the combination of these flexible tubing (flexible injection lines) with the solid wellbore tubing, or by means of at least one flexible multi-channel tubing containing inside at least three fix-attached flexible tubing (channels) of smaller diameter leading into the space in the wellbore and/or pay zone below/behind at least one remotely-adjustable packer connected with the well head that, after reaching the required position, seals off space in the wellbore below the packer and the pay zone (16) against the space above the packer in the wellbore and up to the well head. The invention also includes a device for the implementation of this method.

Methods and systems for increasing the recovery efficiency of a petroleum reservoir. For example, a method for performing a petroleum recovery assessment to increase the recovery efficiency of a petroleum reservoir includes evaluating results associated with a reservoir management analysis for the petroleum reservoir and generating a reservoir management analysis score. The method further includes evaluating results associated with a global benchmark analysis and generating an estimated maximum recovery efficiency for the petroleum reservoir. The method further includes determining key recovery obstacles impeding the petroleum reservoir from achieving the estimated maximum recovery efficiency, and identifying field development opportunities addressing a key recovery obstacle that when implemented, increases a recovery efficiency for the petroleum reservoir closer to the estimated maximum recovery efficiency.

A can include a gas injection mandrel configured to inject a gas into fluids produced into a flow passage of a production string, and a gas dispersal tool including at least one turbulence-inducing structure configured to disperse the gas in the fluids. A method can include connecting a gas dispersal tool in a production string, producing fluids into a flow passage extending longitudinally through the production string, and injecting a gas into the flow passage, thereby causing the gas and the fluids to flow through the gas dispersal tool, and the gas dispersal tool dispersing the gas in the fluids. A gas dispersal tool can include a generally tubular outer housing, a flow passage extending longitudinally through the outer housing, and at least one turbulence-inducing structure in the flow passage, the turbulence-inducing structure being configured to disperse gas in a flow of produced fluid through the flow passage.

Oil recovery can include providing a tubing string and isolation devices to define isolated intervals for an existing well previously operated using plug-and-perf and primary production. Valve assemblies are installed in respective isolated intervals, each valve assembly including at least two valves. The valve can be operated in open and closed configurations, and at least one open configuration provides choked flow via an elongated passage. The valves can have a housing and a shiftable sleeve. The valve assemblies can be operated to provide a desired openness based on the injectivity or other properties by shifting the sleeves of the valves. Different flow resistance levels can be provided to facilitate enhanced operations for water flooding and other oil recovery processes.

The present disclosure describes a method of recovering oil and gas from a hydrocarbon-containing reservoir generally having some degree of water saturation within the reservoir pore network by injecting a gas into the reservoir. The method applicable to reservoirs having high water saturation of about 50 percent or greater. High water saturation in a reservoir can cause excessive amounts of water to be produced to produce the hydrocarbons. Coproduction and management of this water is costly and burdensome to operations leaving many reservoirs of oil and gas are stranded, rendering the production uneconomic. The method described herein addresses this need and other needs. The injection gas (with or without other hydrocarbons) can coalesce with the hydrocarbons contained within the hydrocarbon-containing reservoir to form a continuous phase of hydrocarbons within the reservoir. Once the targeted volume of the injection gas is injected, the flow is reversed producing the gathered hydrocarbons.

A method for fracturing a downhole formation, includes: preparing an energized fracturing fluid including mixing gaseous natural gas and a fracturing base fluid in a mixer; injecting the energized fracturing fluid through a wellhead and into a well; and continuing to inject the energized fracturing fluid until the formation is fractured. An apparatus for generating an energized fracturing fluid for use to fracture a downhole formation, the apparatus includes: a fracturing base fluid source; a natural gas source; and a mixer for accepting natural gas from the natural gas source and fracturing base fluid from the fracturing base fluid source and mixing the natural gas and the fracturing base fluid to generate the energized fracturing fluid.

A well configuration for co-injection processes, wherein a horizontal producer well at the bottom of the pay is combined with injection or injection and producer wells that are vertical and above the lower horizontal production well. This well arrangement minimizes “blanket” effects by non-condensable gases.

Systems and methods for selecting surfactants for use in subterranean formations are provided. In one embodiment, the methods comprise: providing a sample of oil from at least a portion of a subterranean formation; measuring at least one of the total acid number (TAN) and the total base number (TBN) of the oil sample; and selecting a set of surfactants to evaluate for a treatment in at least a portion of the subterranean formation based on at least one of the TAN and the TBN of the oil sample, the set of surfactants selected from the group consisting of: a set of cationic surfactants, a set of anionic surfactants, and a set of zwitterionic surfactants.

The present invention provides a method for enhancing the recovery of oil from a formation. An enhanced oil recovery formulation comprising a gas comprised of a hydrocarbon-containing gas and an ether having from 2 to 4 carbons is injected into an oil-bearing formation to mobilize the oil. The mobilized oil is then produced from the formation.