Abstract: Disclosed herein are methods and systems for membrane carbonation for cultivating microalgae and other microorganisms that utilize a gaseous substrate, as well as to upgrade the quality of mixed-gas streams.

Abstract: The present disclosure relates to systems and methods of enhanced geothermal energy production that transports fluid from existing underground fluid reservoirs to a deeper, higher temperature radiator zone for fluid heating before recovery at the surface. One system includes at least one radiator injection well extending from a subterranean water reservoir of a formation to a radiator zone of the formation that is located at a greater depth than the subterranean water reservoir. The radiator injection well is configured to fluidically couple the subterranean water reservoir with the radiator zone to transfer fluid contained in the subterranean water reservoir to the radiator zone for heating. At least one recovery well extends from the surface to the radiator zone and is configured to recover fluid from the radiator zone that was transferred from the subterranean water reservoir to the radiator zone. The recovered fluid is then used at the surface to generate electricity.

Abstract: A system for improving a steam oil ratio (SOR) includes a boiler fluidly coupled with a downhole portion of a steam system via at least a boiler conduit, wherein the boiler is configured to schedule super-heat delivered to the downhole portion to optimize the SOR associated with the system.

Abstract: Disclosed herein are compositions and methods for reducing fluid loss in a well bore, methods for wellbore strengthening and increasing the integrity of the borehole of an oil or gas well. Also disclosed are methods for artificially increasing the temperature of a subsurface formation in the wellbore to increase the apparent wellbore strength. The mechanism for accomplishing this revolves around increasing fracture propagation pressure by actively manipulating thermal wellbore stresses.

Abstract: A system includes a plug assembly having a housing configured to be positioned within a first passageway formed in a wellhead component. A channel is formed in the housing, and the channel is configured to enable fluid to flow from a bore of the wellhead component into the channel. A sensor is supported by the housing and is configured to measure a condition of the fluid within the channel. An annular seal is configured to extend between an outer surface of the housing and an inner surface of a second passageway formed in a flange that circumferentially surrounds at least part of the plug assembly while the flange is coupled to the wellhead component.

Abstract: Acoustic data can be collected from oil wells having various configurations of tubing and casing and under various operational conditions such as pumping, shut-in, and transition phases such as pressure build up. The acoustic data is collected by a microphone in response to the generation of an acoustic pulse that is transmitted into the well. There is typically substantial noise in the well pipes and this noise can degrade the quality of the reflected data recorded from the acoustic pulse. Much of this noise is produced by the flow of gas in the tubing and associated flow lines. Apparatus for use with the well can be configured to control the state of certain valves which can lead to a reduction of the noise received for the microphone that records the acoustic data.

Abstract: A liquid phase enhanced oil recovery system that, in a stimulation phase, pumps a liquid mixture of propane (C3) and butane (C4) having a starting ratio of C3 to C4 into a well. During a subsequent production phase, liquid C3 and liquid C4 is recovered by a stabilizer from the produced oil, and, in addition, C3 and C4 can be recovered from the produced hydrocarbon vapor and liquefied, The ratio of liquid C3 to liquid C4 can then be re-adjusted and may not be the same as the starting ratio. All of the liquid C3-C4 can be recycled back into the well in subsequent stimulation phases. The method works at relatively low pressures, so that a pump or pumps can be used for stimulation treatment. The site equipment is compact enough that it can be mounted on one or more skids to ensure transportability to be used on other wells.

Abstract: A method of predicting hydraulic fracturing and associated risks of hydraulic fracturing operation is proposed. The methods use the mathematical simulation which allow to predict the geometry of a hydraulic fracture and location of fluids, propping agents (proppant), fibers and other materials therein. Reconsidering the fracturing design allows to remedy the possible risks (overflush, screen-out, bridging, gel contamination, temperature effects).

Abstract: The present disclosure discloses a rotary downhole cavitation generator, including an upper connector, a lower connector, and a casing. Said casing is internally provided with a transmission shaft, an alignment bearing, a drive assembly, a thrust bearing, a rotating disk, a rectification cylinder, an inner sleeve, and an outer sleeve. Said transmission shaft is provided with a deep hole, a diversion hole radially communicating with said deep hole, and a diversion channel radially communicating with said deep hole. Said alignment bearing and said drive assembly are sleeved on an upper end of said transmission shaft, and said rotating disk, said inner sleeve, and said thrust bearing are sleeved on a lower end of said transmission shaft. Said rectification cylinder and said outer sleeve are mounted on an inner wall of said casing, and said upper connector and said lower connector are respectively connected to both ends of said casing.

Abstract: Unconventional hydrocarbon source rock reservoirs can contain the organic material kerogen, intertwined with the rock matrix. The kerogen can alter the tensile strength of the rock and contribute to higher fracture energy needs. To degrade kerogen and other organic materials, oxidizing gasses are dissolved in carbon dioxide (CO2) which is then used as part of a fracturing fluid. The oxidizing gasses can be dissolved directly in the CO2 or generated in situ using precursors.

Abstract: A liquid phase enhanced oil recovery system that, in a stimulation phase, pumps a liquid mixture of propane (C3) and butane (C4) having a starting ratio of C3 to C4 into a well. During a subsequent production phase, liquid C3 and liquid C4 is recovered by a stabilizer from the produced oil, and, in addition, C3 and C4 can be recovered from the produced hydrocarbon vapor and liquefied, The ratio of liquid C3 to liquid C4 can then be re-adjusted and may not be the same as the starting ratio. All of the liquid C3-C4 can be recycled back into the well in subsequent stimulation phases. The method works at relatively low pressures, so that a pump or pumps can be used for stimulation treatment. The site equipment is compact enough that it can be mounted on one or more skids to ensure transportability to be used on other wells.

Abstract: A fluid injection process includes removing a core sample from a low permeability reservoir. The process also includes performing an imbibition test on a plurality of stage one surfactants, each stage one surfactant mixed with a first treatment fluid and using a portion of the core sample to obtain a wettability index or measurement of capillary pressure. The process includes selecting a stage one surfactant and performing an oil recovery test on a plurality of stage two surfactants, each stage two surfactant mixed with a second treatment fluid. The process includes selecting a stage two surfactant and injecting the selected stage one surfactant into a matrix of the low permeability reservoir. In addition, the method includes injecting the selected stage two surfactant into a fracture network of the low permeability reservoir.

Abstract: A process includes injecting mobilizing fluid, including a solvent, through an injection well and into a hydrocarbon-bearing formation. Fluids are produced from the hydrocarbon-bearing formation to a surface through a well, and injection of the mobilizing fluid is discontinued. Gas flow to the surface from the well is inhibited by injecting a loss circulation material that inhibits solvent-vapor flow from exiting the formation through the well such that a fluid column that includes the well kill fluid, the loss circulation material, or a combination thereof is maintained within the well. The well is opened to perform work thereon After degradation of the loss circulation material, injecting the mobilizing fluid and producing the produced fluids is commenced.

Abstract: A first fracturing fluid is pumped through a first wellbore at a first pressure. The first wellbore includes a first vertical section and horizontal section having a first end, intersecting from the first vertical section, and a distal end. A second fracturing fluid is pumped through a second wellbore at a second pressure simultaneously while the first fracturing fluid is pumped through the first wellbore. The second wellbore includes a second vertical section that intersects with the distal end of the horizontal section. The first pressure and the second pressure result in the first fracturing fluid and the second fracturing fluid intersecting at a fracture point within the horizontal section at a third pressure. The first fracturing fluid and the second fracturing fluid each experience a respective pressure drop traveling through their respective wellbores to the fracture point/. The respective pressure drops result in the third pressure.

Abstract: Thermal recovery methods for recovering viscous hydrocarbons from a subterranean formation. The thermal recovery methods include performing a plurality of injection cycles. Each injection cycle in the plurality of injection cycles includes injecting a heated solvent vapor stream into a heated chamber that extends within the subterranean formation and fluidly contacting the viscous hydrocarbons with the heated solvent vapor stream to generate mobilized viscous hydrocarbons. Each injection cycle also includes injecting a steam stream into the heated chamber. The thermal recovery methods further include producing a chamber liquid and/or mobilized viscous hydrocarbons from the subterranean formation.

Abstract: The embodiments herein relate generally to subterranean formation operations and, more particularly, to surfactant flowback aids for use in subterranean formation operations. The surfactant flowback aid composition may comprise an aqueous phase comprising an aqueous base fluid, a surfactant blend, and a demulsifier. The surfactant blend may comprise a C8-C18 alcohol ethoxy-late; a fatty acid alkanolamide; and optionally, a surfactant selected from the group consisting of a non-ionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and any combination thereof. The demulsifier may be selected from the group consisting of a desalter agent to separate water from crude oil, a treater agent to flocculate submicron particulates from crude oil, and any combination thereof.

Abstract: The present disclosure relates to a particularly effective well configuration that can be used for single well cross steam assisted gravity drainage (SW-XSAGD) wherein a single well has multiple injection sections each separated by a production segment that is completed with passive FCDs to control steam flashing.

Abstract: A system of performing a well operation including determining a minimum horizontal in-situ stress of a subterranean formation, comprising: a first component configured to create a measured pressure response from data of a well injection test; a simulation component configured to generate a simulated pressure response with a selected value of a simulated minimum horizontal in-situ stress; and an arrangement to compare at least a portion of the simulated pressure response to a corresponding portion of the measured pressure response to resolve a difference; whereby the minimum horizontal in-situ stress of the formation may be equated to a value of the simulated minimum horizontal in-situ stress corresponding with a lesser resolved difference. Further aspects of the disclosure include novel methods.

Abstract: A system and method is provided for upgrading a continuously flowing process stream including heavy crude oil (HCO). A reactor receives the process stream in combination with water, at an inlet temperature within a range of about 60° C. to about 200° C. The reactor includes one or more process flow tubes having a combined length of about 30 times their aggregated transverse cross-sectional dimension, and progressively heats the process stream to an outlet temperature T(max)1 within a range of between about 260° C. to about 400° C. The reactor maintains the process stream at a pressure sufficient to ensure that it remains a single phase at T(max)1. A controller selectively adjusts the rate of flow of the process stream through the reactor to maintain a total residence time of greater than about 1 minute and less than about 25 minutes.

Abstract: Systems and methods for testing properties of a test sample with a tri-axial nuclear magnetic resonance include a tri-axial load frame encasing a tri-axial load cell having a tri-axial sample holder and a piston assembly. A radial space surrounds the tri-axial sample holder. The tri-axial load frame further encases at least one end cap operable to contact the tri-axial load cell, and a nuclear magnetic resonance instrument. An axial pressure line is in fluid communication with the piston assembly, a confining pressure line is in fluid communication with the radial space, and a pore pressure line in fluid communication with the test sample. The axial pressure line, the confining pressure line, and the pore pressure line are independent and separate fluid flow paths.

Abstract: Systems and methods for performing steam injection operations in heavy oil formations using a fully-coupled thermo-hydro-mechanical model for improved steam penetration during the steam injection operations.

Abstract: The present disclosure relates to, according to some embodiments, an extraction process for recovering an oil from an oil reservoir comprising a mobile water. The extraction process includes the step of injecting a first solvent into the oil reservoir through the at least one injection well to form a first mixture, the first mixture comprising the first solvent, a first portion of mobile water, and a first portion of oil.

Abstract: A method for modeling reservoir souring using object-oriented numerical solutions separate from reservoir topography is described. Specifically, flow physics are separated into one or more objects, along with one or more H2S generation mechanisms, for modeling on time and spatial scales separate from field scale modeling.

Abstract: Methods for enhanced oil recovery from subterranean formations by treating a produced water prior to injection into the subterranean hydrocarbon reservoir and manipulating produced water compositions to increase the rate and/or amount of oil that is recovered from producing wells and/or a hydrocarbon reservoir. The treatment of the produced water can increase the pH of the water from about 0.75 to about 2.0.

Abstract: A method for increasing efficiency in emulsion production for a steam-assisted gravity drainage (SAGD) oil well system includes generating a causal model of the SAGD oil well system and training the causal model of the SAGD oil well system utilizing historical time series data relating to one or more SAGD oil wells at one or more SAGD production sites of the SAGD oil well system. The historical time series data is obtained from a plurality of sensors in the SAGD oil well system. The method also includes utilizing the causal model to determine a forecast emulsion production and a forecast set of control parameters associated with one or more of the SAGD production sites of the SAGD oil well system. The method further includes adjusting a set of controls of the SAGD oil well system based on the forecast emulsion production and the forecast set of control parameters and subject to one or more constraints associated with the SAGD oil well system.

Abstract: A family of organic tracers is proposed for single well chemical tracer tests, for example for the measurement of residual oil in petroleum reservoirs. The tracers consist of at least one ester of (hydroxyalkyl) benzoic acid of formula (I), wherein at least one of R1 to R5 is a hydroxy alkyl group —R7—OH and each of the remaining R1 to R5 groups is independently selected from H, F, Cl, Br, I, CF3CF2Cl, CFCl2, CCl3 and at least one of these remaining R1 to R5 groups is not H, R6 is selected from CH3, C2H5, C3H7, C4H9, CF3, CH2CF3, CCl3, CH2CCl3, CH2CHCl2, CH2CH2Cl, CH2CF3, CH2CHF2, CH2CH2F, CH2CH2CH2F, CH2CH2CHF2, CH2CH2CF3, CH2CH2CH2Cl, CH2CH2CH—Cl2, CH2CH2CCl3, C3H6F, C3H5F2, C3H4F3, C3H6Cl, C3H5Cl2, C3H5Cl3 or a halogenated (hydroxymethyl)phenol and R7 is selected from CH2, C2H4, C3H6, C4H8.

Abstract: Treating a gas condensate reservoir having a porous formation material includes introducing a formation treatment fluid to the gas condensate reservoir and maintaining the formation treatment fluid in the gas condensate reservoir. The formation treatment fluid is a dispersion including metal oxide nanoparticles, and the gas condensate reservoir includes discrete portions of condensate in contact with the porous formation material.

Abstract: Systems and methods are disclosed to analyze sediment and sedimentary rock properties. Example systems and methods transform data representing physical particles and burial histories into a three-dimensional representation of solids and pores in sediments and sedimentary rocks by analyzing effects of deposition, grain rearrangement, compaction, and chemical reactions. Resulting output may include three-dimensional representations which may be the basis of physical objects or media for laboratory tests. In an example, output may provide a basis for evaluating present-day properties for areas where sample material is unavailable, reconstructing properties for times in the geologic past, and forecasting the effects of engineering and industrial activities on properties.

Abstract: Systems and methods for modeling subterranean formations that include both gaseous hydrocarbons and adsorbed hydrocarbons. The systems and methods include determining a formation volume factor for gaseous hydrocarbons that may be present within the subterranean formation and correcting the formation volume factor to generate a compensated formation volume factor. The systems and methods further may include simulating a fluid flow within the subterranean formation, with the simulating being based, at least in part, on the compensated formation volume factor. Correcting the formation volume factor may include adjusting the formation volume factor based, at least in part, on a fraction of the adsorbed hydrocarbons within the subterranean formation that desorbs from the subterranean formation and/or transitions to gaseous hydrocarbons during production of the gaseous hydrocarbons from the subterranean formation.

Abstract: Provided are oil recovery techniques, which may include enhanced oil recovery techniques in which a heated combination of water vapor (steam) and dimethyl ether (DME) vapor are injected into an oil reservoir, such as containing heavy oil and/or bitumen, to facilitate extraction of the oil from the reservoir.

Abstract: In one aspect, a method of recovering hydrocarbons from a subterranean zone includes flowing carbon dioxide in a first state into the subterranean zone including hydrocarbons, wherein a density of the carbon dioxide in the first state is greater than a density of carbon dioxide in a gaseous state, and recovering at least a portion of the hydrocarbons in the subterranean zone in response to flowing carbon dioxide in the first state into the subterranean zone.

Abstract: Enhanced oil recovery is practiced in long lateral wellbores by drilling at least one of a sidetrack lateral wellbore end a branch lateral wellbore from the main lateral wellbore. After production of the sidetrack lateral wellbore or the branch lateral wellbore, EOR flood fluid is pumped info the at least one of the sidetrack lateral wellbore and the branch lateral wellbore and recovered hydrocarbons and EOR flood fluid are produced from the main lateral wellbore, or vice versa.

Abstract: A method of hydraulically fracturing a subterranean formation is provided. The method comprises generating a primary fracture using a fracturing fluid. The method further comprises extending the primary fracture and/or creating micro fractures about the primary fracture by initiating a chemical reaction such as an exothermic reaction at about the primary fracture. In one embodiment, the fracturing fluid is used to convey one of the reactive components participating in the chemical reaction.

Abstract: A method of recovering hydrocarbons from a subterranean formation includes placing a wellbore in the formation, wherein the wellbore is approximately horizontal in the formation; forming one or more fractures in the formation in fluid communication with the wellbore; recovering hydrocarbons from the formation through the wellbore; injecting a volume of fluid comprising greater than 98 mass % water and greater than 0.005 mass % active surfactant into the formation through the wellbore, wherein at least 10 mass % of said volume is injected at a bottom hole pressure at the heel of the wellbore that is less than the minimum horizontal stress in at least a portion of the overburden and at least 5 mass % of said volume is injected at a bottom hole pressure at the heel of the wellbore that is greater than the median minimum horizontal stress in the subterranean formation; and subsequently recovering in situ hydrocarbons from the subterranean formation.

Abstract: The application is related to improving recovery of fracturing fluids from subterranean target earth intervals. The application is also related to improving hydrocarbon productivity of subterranean target earth intervals. The application is also related to controlling the development of fractures in subterranean target earth intervals.

Abstract: Improved SAGD methods for recovering heavy oil from underground formations. In a first aspect a method is provided for drilling, using multi-lateral drilling techniques, a series of horizontal collector wells from a vertical shaft of a production well, below and parallel to an injection well. In a further alternative to the typical SAGD configuration having injector and producer well drilled from the same end of a region under development, the production well is instead drilled at an end of a region of development opposite to an end of such region at which an injector well is drilled. Lastly, in yet another aspect, the invention comprises a method for rejuvenating an existing SAGD well pair, comprising drilling a further production well or wells at an opposite end of said formation at which an existing injector well was drilled, preferably using multi-lateral drilling techniques.

Abstract: A stabilized nano-Fe6-iron-crown ether complex is added to a heavy oil to reduce the viscosity of the heavy oil. The complex may be formed by preparing a solution of an iron salt and an oligomer crown compound in dialkylamine or diethylamine. Sodium tetrahydroboron (NaBH4) and dialkylamine or ethylendiamine are added at a temperature of 0-10° C. The mixture is heated to room temperature and boiled, thereby converting the formed iron (II)-borhydride complex (Fe(BH4)2) to a crown ether—iron-hydride complex [CWFe06].(2H)6. At higher temperature this last complex is converted to the Fe06-crown nanocomposite complex.

Abstract: Methods of resource recovery include reagents placed in a subterranean formation. The reagents generate heat, hydrogen gas and alkalinity which changes fluid flow characteristics. The forces of the reactions create fractures and cracks far from the well bore. These cracks and fractures are sealed if water is being transmitted through or near the reactions. As a result, the targeted fluids more efficiently flow to the well, along with decreased amounts of water waste, while stimulating generation of biogenic gases in the subterranean formations.

Abstract: A device is provided for extracting a hydrocarbon-containing substance from a reservoir. Thermal energy can be applied to the reservoir in order to reduce the viscosity of the substance. The device includes at least one conductor loop for inductively supplying electric current, to provide electric and/or electromagnetic heating, and a fluid conducting device for transporting and introducing a solvent fluid into the reservoir, to further reduce the viscosity of the substance.

Abstract: A well production and injection string includes a plurality of spaced apart packers each adapted to seal with a wall of the wellbore. A plurality of flow control devices are provided in the string, distributed between pairs of adjacent packers. The flow control devices are adapted to communicate flow between an interior and an exterior of the string with less restriction to flow from the interior to the exterior of the string than to flow from the exterior to the interior of the string.

Abstract: A dual-purpose tool can be used for steam injection and production in a wellbore. A mandrel deploys in the wellbore to communicate steam in a steam injection operation and to communicate production fluid from the wellbore during production operations. A distributor on the mandrel has nozzles for injecting steam into the wellbore and has production valves for producing fluids from the wellbore. A screen can be used to screen production fluids as they are produced through the production valves. The nozzles can also allows produced fluids to flow into the mandrel, or backflow valves can be used to restrict flow of produced fluids through the nozzles while permitting the flow of steam out of the nozzles.

Abstract: Disclosed is a process for in situ upgrading of a heavy hydrocarbon comprising the steps of: (a) positioning a well in a reservoir containing a heavy hydrocarbon having an initial API gravity of less than or equal to about 20, an n-heptane asphaltene content as measured by the ASTM D-6560 of at least about 1 wt. %, and a viscosity at 35° C. greater than about 350 centistokes (cSt); (b) injecting one or more hydrocarbon solvents and one or more asphaltene precipitant additives into the well in any order at a ratio by volume of the solvent to the heavy hydrocarbon of at least from about 0.1:1 to about 20:1 under reservoir conditions so as to provide an upgraded hydrocarbon in the reservoir, wherein the upgraded hydrocarbon has an improved API gravity greater than the initial API gravity, a reduction in the asphaltene content, and a lower viscosity; and (c) producing the upgraded hydrocarbon from the well.

Abstract: A method and apparatus for extracting geothermal energy from a subterranean thermal reservoir through a wellbore where the heat exchange fluid is introduced at a slower velocity than the velocity at which the fluid is extracted. The method and apparatus further comprises a gas zone near the top of the wellbore to maintain the thermal energy of the heat exchange fluid. In one embodiment, a portion of the casing of the wellbore can directly contact the subterranean environment. Alternatively, a thermally conductive wall comprising a thermally conductive material can surround a portion of the casing of the wellbore. Further, the inner and/or outer surface of the pipes and conduits of the disclosed method and apparatus can include modified surface features that influence the flow and/or thermal conductivity of the heat exchange fluid.

Abstract: A completion for steam injection and production includes a production tubing connected to a stinger, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool, a downhole steam generator (DSG) having a discharge conduit extending from the DSG to the inverted Y-tool, a bypass conduit extending from the Y-tool to the DSG, and a fuel supply tubing connected to the DSG. An artificial lift device may be incorporated into the completion.

Abstract: A system usable with a well includes a waveform generator for enhancing fluid recovery from a reservoir by controlling a production pump or an injection pump downhole in the well with waveform signals to create a pressure wave which propagates into the reservoir and enhances the recovery of the fluid.

Abstract: A method for injecting treatment chemical into a well includes selecting times at which to operate a chemical dispenser to inject a selected amount of treatment chemical into a well. At each selected time whether a wellbore pump is operating is determined. If the pump is operating the selected amount of treatment chemical is dispensed into the well. If the pump is not operating, no chemical is dispensed and a counter is incremented. At each subsequent selected time, the determining whether the well pump is operating is repeated. When a subsequent selected time coincides with a time at which the well pump is determined to be operating, the chemical dispenser is operated to inject a product of the number in the counter plus one, and the selected amount of treatment chemical into the well.

Abstract: The method can be used in the oil-producing industry for intensifying the production of oil and for increasing the intake capacity during the working of the bottom region of a seam and completion of wells. For producing pressure draw-down and repressuring cycles at the well bottom there is periodically changed the direction of flow of working liquid using controlled movement of jet pump. The value of maximal pressure draw-down is regulated, and periods of pressure draw-down and repressuring action are implemented with equal values of volumes of the inflow and the liquid pumpable into the seam in one cycle. These volumes in each subsequent cycle are increased. The cycles are continued until the increase in the values of the liquid volumes ceases. Chemical reagents are then pumped into the seam. If necessary, the cycles are repeated. The stimulation of the bottom region of the seam is completed with a pressure draw-down. 14 variants of formula.

Abstract: A process for utilizing microwaves to heat H2O within a subterranean region wherein the heated H2O contacts heavy oil in the subterranean region to lower the viscosity of the heavy oil and improve production of the heavy oil.

Abstract: Casing valves for selective well stimulation and control. A well system includes at least one valve interconnected in a casing string operable via at least one line external to the casing string to selectively control fluid flow between an exterior and interior of the casing string, and the casing string, valve and line being cemented in a wellbore. A method of selectively stimulating a subterranean formation includes: positioning a casing string in a wellbore, the casing string including spaced apart valves operable via a line to selectively control fluid flow between an interior and exterior of the casing string; and for each of multiple intervals of the formation in sequence, stimulating the interval by opening a corresponding one of the valves, closing the remainder of the valves, and flowing a stimulation fluid from the casing string into the interval.

Abstract: Methods and systems for completing a well including injecting a stimulation fluid to stimulate a first interval in the reservoir. The stimulation fluid is at a pressure sufficient to open a number of check valves in the first interval, allowing stimulation fluid to flow into the first interval. A number of ball sealers configured to block flow through the check valves are dropped into the well to stop the flow of the stimulation fluid into the first interval and begin treatment of a second interval. The stimulation fluid is injected to stimulate a subsequent interval with pressure sufficient to open a number of check valves in the subsequent interval, allowing stimulation fluid to flow into the subsequent interval. The dropping of ball sealers is repeated until all intervals are treated.