Abstract: Computer-implemented methods, systems, and non-transitory computer-readable medium having computer program stored therein are provided to enhance the accuracy and efficiency of modeling a core sample from images of two-dimensional transverse sections of a core sample. Embodiments of the invention include, for example, image registering a plurality of images of transverse sections of a core sample to produce aligned transverse sections by approximating the circular location of the boundary of the transverse section and aligning the images based on center points of the approximated circles.

Abstract: Method for acquiring and evaluating geometry of a well includes deploying at least one grid of geophysical sensors, wherein the at least one grid of the sensors is deployed in a 2D or 3D configuration; acquiring an initial geophysical survey of geophysical parameters of the well; fracturing the well creating a fracture while simultaneously; injecting an electrically active proppant into the fracture, wherein the electrically active proppant is injected into the fracture during fracturing, after fracturing or during and after fracturing; continuously acquiring a geophysical survey of geophysical parameters of the well during the fracturing; and acquiring a final geophysical survey of geophysical parameters of the fracture upon completion of the fracturing.

Abstract: A method of fracturing multiple zones within a wellbore formed in a subterranean formation is carried out by forming flow-through passages in two or more zones within the wellbore that are spaced apart from each other along the length of a portion of the wellbore. The flow-through passages within each zone have different characteristics provided by orienting the flow-through passages in directions in each of the two or more zones relative to a selected direction to provide differences in fracture initiation pressures within each of the two or more zones. A fracturing fluid is introduced into the wellbore in a fracturing treatment. The fracturing fluid in the fracturing treatment is provided at a pressure that is above the fracture initiation pressure of one of the two or more zones to facilitate fracturing of said one of two or more zones while remaining below the fracture initiation pressure of any other non-fractured zones of the two or more zones.

Abstract: A pressure pulse is initiated from the wellbore into the fractured formation where the frac fluid brings into the fractures a material that is responsive to the pressure pulse alone. Alternatively, or with a combination with a wellbore pressure pulse, well conditions such as time exposure and temperature can initiate local pressure pulses within the fracture with the result being signal generation of an electromagnetic signal that is measured with multiple sensors to allow triangulation of the location of the fracture extremities. The material can be a piezoelectric material that responds to the pressure pulse or ferromagnetic materials that similarly respond to the pulse to create the measured signals. The material can be delivered initially with the frac fluid or at different points in time during the fracture operation. Different materials with unique signal generating characteristics can be used to get a clearer picture of the extent of the fracture.

Abstract: During a hydraulic fracturing treatment operation, one of three operational parameters may be modified in a successive stage by adjustment of another operational parameter to attain a fracture of length DPST. The operational parameters include the proppant size, viscosity of the transport fluid and injection rate of the transport fluid.

Abstract: A method of creating a step-change in proppant concentration in a fracturing fluid at a desired location within the conduit or wellbore of an oil or gas well includes connecting an in-line mixer at an end of a conveyance. The in-line mixer is then placed within a conduit proximate to the desired location, and a flow of a clean fluid is provided from an upper portion of the conduit past the in-line mixer and into a lower portion of the conduit. A proppant slurry is introduced into the conveyance and injected into the clean fluid from the in-line mixer to generate a first step-change from the clean fluid to a flow of a mixture of the proppant slurry and the clean fluid within the desired location.

Abstract: Methods are provided for identifying the location and height of induced subterranean formation fractures and the presence of any associated frac-pack or gravel pack material in the vicinity of the borehole using pulsed neutron capture (PNC) logging tools. The proppant/sand used in the fracturing and packing processes is tagged with a thermal neutron absorbing material. When proppant is present, increases in detected PNC formation and/or borehole component cross-sections, combined with decreases in measured count rates, are used to determine the location of the formation fractures and the presence and percent fill of pack material in the borehole region. Changes in measured formation cross-sections relative to changes in other PNC parameters provide a relative indication of the proppant in fractures compared to that in the borehole region.

Abstract: A shear tester for in-situ determination of rock formation geomechanical properties is provided. The tester has a radially expandable cylindrical membrane, a metal sheath covering at least a portion of the outer surface of the membrane, at least one stud fixed on the sheath, at least one cone fixed on each of the at least one stud, and a piston operable to apply an upward axial force on the metal sheath. A device for the same use comprises the shear tester and a pressuremeter. A method of using the shear tester comprises applying a normal force to the formation by expanding the membrane until at least one of the at least one cone penetrates the rock formation and applying an upward axial force to the at least one of the at least one cone by operating the piston until at least a portion of the rock formation shears.

Abstract: A method for determining wettability of a solid, such as a reservoir rock material includes disaggregating the material, for example by grinding and placing the disaggregated material on the surface of the fluid. The wettability is analyzed based on whether a portion of the material floats on or sinks into the fluid. The method is well suited for heterogeneous solid materials that have mixed wetting characteristics and/or have varying surface types. The fluid can be evaluated as a potential treatment fluid or a component thereof that can be used for treating the rock formation. For example, the potential treatment fluid can include a surfactant or an oxidizing agent. A simple observation can be made whether substantially all of the material placed on the surface of the fluid sinks into the fluid, or the portions of floating and sinking material can be weighed.

Abstract: There are provided high power laser perforation, hydraulic fracturing systems, tools and methods for the stimulation and recovery of energy sources, such as hydrocarbons, from a formation. These systems, tools and methods provide predetermined laser beam energy patterns, to provide for the down hole volumetric removal of custom geometries of materials, sealing of perforations, reperorations, refractures and other downhole actives.

Abstract: A method of fracturing multiple zones within a wellbore formed in a subterranean formation is carried out by forming flow-through passages in two or more zones within the wellbore that are spaced apart from each other along the wellbore. The flow-through passages are arranged into clusters, where the directions of all flow-through passages, which belong to the same cluster, are aligned within a single plane (cluster plane). At least one cluster of flow-through passages is formed in each zone. The clusters within each zone have characteristics different from those of other zones provided by orienting the cluster planes at different angles relative to principal in-situ stresses and by placing them into different locations along the wellbore in each of the two or more zones. A propellant pre-fracturing treatment is then performed in the two or more zones to create initial fractures (pre-fractures) in each of the two or more zones.

Abstract: A downhole system including a downhole device for data acquisition during fracing operations is disclosed. It includes a bypass device (102) operatively coupleable to for instance a frac plug (10) and is adapted to allow downhole fluid flow through the bypass device (102) and frac plug (10) but also permits the closure of that path whilst providing at least one second fluid path (120) for fluid communication between at least one data acquisition device (108) provided to detect at least one physical property such as pressure and a region inside the wellbore located uphole of the bypass device (102).

Abstract: A method and system for monitoring well operations are provided. Acceleration data is generated from vibration signals collected from a well and the data is processed to indicate a well condition such as the actuation of a device and the movement and location of an actuation device.

Abstract: An apparatus and method for well control and monitoring including an independent web server computer integrated with a pump controller located at each well in an oil field. The well controller locally controls the well pump, processes well and pump data, generates surface and downhole cards, and communicates production reports, recommendations for production improvements, and production statistics to remote sites via the internet. The controller can be queried remotely to provide production reports, etc. Furthermore, the controller can initiate alerts via email, text messaging, or internet messaging, for example, during fault conditions.

Abstract: A gel barrier may be created within an annulus in a one-step operation by combining two or more solutions within the annulus. The two solutions may include a first solution, such as a silicate solution, and a second solution that may be an aqueous hardener solution. Once the two solutions are combined and subsequently reacted together, the forming of a gel barrier may occur between a plurality of zones along the annulus. The gel barrier may then prevent a fluid from traveling between adjacent zones of the wellbore annulus.

Abstract: In or near real-time monitoring of fluids can take place using an opticoanalytical device that is configured for monitoring the fluid. Fluids can be monitored prior to or during their introduction into a subterranean formation using the opticoanalytical devices. Produced fluids from a subterranean formation can be monitored in a like manner. The methods can comprise providing at least one fracturing fluid component; combining the at least one fracturing fluid component with a base fluid to form a fracturing fluid; and monitoring a characteristic of the fracturing fluid using a first opticoanalytical device that is in optical communication with a flow pathway for transporting the fracturing fluid.

Abstract: The present invention relates to producing oil from an oil-bearing geological formation using a selection process. The process includes selecting a treatment option such as carbon dioxide flooding for enhancing oil recovery from a geological formation in a remote location. Various characteristic properties such as a physical or chemical property of the oil or rock may be used in the selection process and the carbon dioxide may be captured from a combustion process.

Abstract: A method may include modeling a bulk electromagnetic (EM) characteristic of a composite material including a fracturing fluid, a proppant, and a sensing additive. The method may further include generating a modeled propped fracture pattern for a subterranean formation having the composite material injected therein, and generating a three dimensional (3D) arrangement of cells based upon the bulk EM characteristic and the modeled propped fracture pattern using an effective medium theory (EMT) model, with each cell having a modeled localized EM characteristic associated therewith. The method may also include injecting the composite material into the subterranean formation to cause an actual propped fracture pattern, collecting EM data based upon the sensing additive within the actual propped fracture pattern, and determining a respective actual EM characteristic for each cell based upon the modeled localized EM characteristics and the collected EM data.

Abstract: A method including providing sensors in injection and observation wells; increasing pressure within the injection well until a fracture extends from an initiation location through a portion of a subterranean formation to an intersection location in the observation well, wherein increasing pressure within the injection well comprises introducing fluid into the injection well; obtaining a measurement indicative of fracture initiation from the first sensor; determining a height of the fracture at the injection well; obtaining a measurement indicative of fracture intersection from the second sensor; determining a volume of fluid introduced between the fracture initiation and the fracture intersection; determining a distance between the initiation location and the intersection location; determining a time lapse between the fracture initiation and the fracture intersection; and using the determined values, calculating a hydraulic fracturing characteristic.

Abstract: A method for predicting hydrocarbon recovery in a subterranean formation may include generating pre-heating data associated with fracturing in a sample from the subterranean formation, heating the sample with RF power to cause additional fracturing in the sample, and generating post-heating data associated with additional fracturing in the sample after heating with RF power. The method may also include detecting change between the pre-heating data and post-heating data, and predicting hydrocarbon recovery from the subterranean formation based upon the detected change.

Abstract: In some aspects, response data from an injection test of a subterranean region are accessed. An injection treatment is designed based on the response data. The response data are acquired during a series of injection periods and shut-in intervals of the injection test. Each of the injection periods is followed by a respective one of the shut-in intervals.

Abstract: In some aspects, response data from an injection test of a subterranean region are received during an injection treatment of the subterranean region. The injection treatment is modified based on the response data. In some instances, the response data are acquired during a series of injection periods and shut-in intervals of the injection test. Each of the injection periods is followed by a respective one of the shut-in intervals.

Abstract: A completion system is disclosed that includes an outer completion string having at least one sand screen arranged thereabout, one or more control lines extending externally along the outer completion string and having one or more gauges operatively coupled thereto and arranged adjacent the at least one sand screen, the one or more gauges being configured for real-time monitoring and reporting of well environment parameters, a service tool arranged within the outer completion string and having an inner tubing that defines a valve conduit, and a valve arranged within the service tool and being movable between a first position, where fracturing fluid is allowed to circulate through the at least one sand screen and the valve and into the valve conduit, and a second position, where the valve prevents the fracturing fluid from entering the valve conduit.

Abstract: In some aspects, an injection rate of an injection test applied to a subterranean region is controlled. The injection test includes a series of injection periods and shut-in intervals. Each of the injection periods is followed by a respective one of the shut-in intervals. The subterranean region is monitored during the injection test.

Abstract: Methods of treating hydrocarbon containing formations are described herein. A method for treating a mudstone formation includes providing a substantially horizontal or inclined wellbore to mudstone formation; providing acid to the portion of mudstone formation such that a size of the fractures is increased; and allowing hydrocarbons to flow through the fractures.

Abstract: A method of stimulating a subterranean formation is provided. The method includes determining a final fracture spacing. The method includes creating a first set of fractures at a first fracture spacing, the first fracture spacing being larger than the final fracture spacing. The method includes allowing production of fluids from the formation through the well bore via the first set of fractures for a period of time. The method includes, after the period of time, creating a second set of fractures. The final fracture spacing is less than or equal to an average fracture spacing between the first set of fractures and the second set of fractures.

Abstract: The invention relates to a method of generating a network of fractures in a rock formation for extraction of hydrocarbon or other resource from the formation. The method includes the steps of i) enhancing a network of natural fractures and incipient fractures within the formation by injecting a non-slurry aqueous solution into the well under conditions suitable for promoting dilation, shearing and/or hydraulic communication of the natural fractures, and subsequently ii) inducing a large-fracture network that is in hydraulic communication with the enhanced natural fracture network by injecting a plurality of slurries comprising a carrying fluid and sequentially larger-grained granular proppants into said well in a series of injection episodes.

Abstract: Apparatus and methods for delivering and placing proppant to a subterranean formation fracture including identifying control variables and uncertain parameters of the proppant delivery and placement, optimizing a performance metric of the proppant delivery and placement under uncertainty, calculating sensitivity indices and ranking parameters according to a relative contribution in total variance for an optimized control variable, and updating a probability distribution for parameters, repeating optimizing comprising the probability distribution, and evaluating a risk profile of the optimized performance metric using a processor. Some embodiments may deliver proppant to the fracture using updated optimized values of control variables.

Abstract: Method of a formation hydraulic fracturing provides injection of a hydraulic fracturing fluid into a borehole with the increase of a fluid flow rate to a working value. During the injection a power consumption of a pump used for the injection is measured continuously. A pump power consumption jump indicates the fracturing fluid flow turbulization in the borehole.

Abstract: A method of inducing fracture complexity within a fracturing interval of a subterranean formation is provided. The method comprises defining a stress anisotropy-altering dimension, providing a straddle-packer assembly to alter a stress anisotropy of a fracturing interval, based on defining the stress anisotropy-altering dimension, isolating a first fracturing interval of the subterranean formation with the straddle-packer assembly, inducing a fracture in the first fracturing interval, isolating a second fracturing interval of the subterranean formation with the straddle-packer assembly, inducing a fracture in the second fracturing interval, wherein fracturing the first and second fracturing intervals alters the stress anisotropy within a third fracturing interval, isolating the third fracturing interval with the straddle-packer assembly, and inducing a fracture in the third fracturing interval.

Abstract: A method for determining fracture plane orientation from seismic signals detected above a subsurface formation of interest includes detecting seismic signals using an array of seismic sensors deployed above the subsurface formation during pumping of a hydraulic fracture treatment of the subsurface formation. A time of origin and a spatial position of origin (hypocenter) of microseismic events resulting from the hydraulic fracture treatment are determined. Time consecutively occurring ones of the hypocenters falling within a selected temporal sampling window are selected. A best fit line through the selected hypocenters using a preselected linear regression coefficient is determined. The selecting hypocenters and determining best fit lines is repeated for a selected number of windows.

Abstract: A method of designing a well control operation includes obtaining sub-surface data related to a formation surrounding a well, building a geomechanical model of the formation based on the sub-surface data, obtaining operational data related to the well control operation, performing, on a processor, a hydraulic fracture simulation of the formation, wherein the simulation is based on the operational data and the geomechanical model, and determining an estimated volume of fluid required for a fracture to breach an upper surface of the formation.

Abstract: This application relates to methods and apparatus for monitoring hydraulic fracturing during oil/gas well formation. A fiber optic cable (102) deployed down a well bore (106), which may be the well bore in which fracturing is performed, is interrogated to provide a distributed acoustic sensor. Data is sampled from at least one longitudinal sensing portion of the fiber and processed to provide at least fracturing characteristic. The fracturing characteristic may comprise the characteristics of high frequency transients indicative of fracturing events (606). The intensity, frequency, duration and signal evolution of the transients may be monitored to provide the fracturing characteristic. Additionally or alternatively the fracturing characteristic may comprise the longer term acoustic noise generated by fracture fluid flow to the fracture sites. The intensity and frequency of the noise may be analyzed to determine the fracturing characteristic. The method allows real-time control of the fracturing process.

Abstract: A method of analyzing a wellbore fluid that includes treating a wellbore fluid with an emulsifying fluid, the emulsifying fluid comprising: a hydroxylated ether; an amphoteric chemotrope; and testing the treated wellbore fluid for at least one of turbidity and total suspended solids is disclosed. Methods of cleaning wellbores are also disclosed.

Abstract: A method of servicing a subterranean formation comprising providing a wellbore penetrating the subterranean formation and having a casing string disposed therein, the casing string comprising a plurality of points of entry, wherein each of the plurality of points of entry provides a route a fluid communication from the casing string to the subterranean formation, introducing a treatment fluid into the subterranean formation via a first flowpath, and diverting the treatment fluid from the first flowpath into the formation to a second flowpath into the formation.

Abstract: The methods described are for determining distribution, orientation and dimensions of networks of hydraulically-induced fractures within a subterranean formation containing fluids. Micro-seismic events are generated, after cessation of fracturing and establishment of fracture networks, by particles introduced into the fractures which are capable of explosive or chemical reaction. In one method, attachment site particles are positioned within the formation during fracturing and additional reactive particles are later introduced. The reactive particles attach to the attachment sites and, upon a triggering event, react to produce micro-seismic events. The waves generated by the micro-seismic events are used to provide mapping of the effective fracture space. Additionally, time-lapse mapping is provided with use of “species” of attachment sites and reactive particles.

Abstract: Systems and methods for improving reservoir fluid recovery from fractured subterranean formations. The methods may include injecting a pressurizing fluid into an injection fracture that extends within a subterranean formation and producing a produced fluid from a production fracture that extends within the subterranean formation. The production fracture is spaced apart from the injection fracture and is in indirect fluid communication with the injection fracture via a portion of the subterranean formation that extends therebetween and the pressurizing fluid injection provides a motive force for the production of the produced fluid. The methods further include injecting a foaming agent into the production fracture to limit production of the pressurizing fluid from the production fracture. The systems may include hydrocarbon production systems that may be utilized to perform the methods and/or that may be created while performing the methods.

Abstract: A system and method for fracturing a well, wherein the system can comprise a base pipe comprising an insert port capable of housing a stop ball partially within the chamber of it, and a sliding sleeve. The sliding sleeve can comprise a first sleeve with an in inner surface. That inner surface can comprise a void. The first sleeve can be maneuverable into two positions. In the first position, the void can rest on a surface of the base pipe not comprising an insert port. Such positioning can prevent a stop ball from exiting the chamber of the base pipe. In the second position, the void can rest over an insert port. Such positioning can allow the stop ball to the chamber of said the base pipe and to enter the void.

Abstract: A system and method for detecting screen-out using a fracturing valve for mitigation, wherein the fracture method can comprise fracturing a well using a fracturing valve, while a downhole pressure is less than a predetermined threshold. The method can also comprise actuating by automated process the fracturing valve from a fracturing position to a nonfracturing position upon detecting by a pressure sensor in the wellbore that the downhole pressure has reached said predetermined threshold.

Abstract: A method of establishing fluid communication between a well pair in an oil-sand reservoir, where dilatable oil sands in the reservoir form a barrier to fluid communication between the well pair. Steam or water is circulated within at least one well to a region of the oil sands adjacent to the well. The steam or water pressure is increased to a dilation pressure sufficient to dilate the oil sands in the region. While circulating steam or water within the well at a substantially steady state, the steam or water pressure is maintained at a level sufficient to enlarge the dilated region, until detection of a signal indicative of fluid communication between the well pair. The rates and pressures of steam or water injection and production may be monitored and adjusted to vary a bottom-hole pressure in the well.

Abstract: The invention relates to the calculation of parameters to inform hydraulic stimulation of non-conventional hydrocarbon-bearing rock formations, such as shales. Unlike conventional formations, non-conventional formations tend to display elastic-plastic behavior and have stress-strain characteristics which with substantial non-linear regions. A parameter which has been termed Elastic Index (EI) is proposed, together with a demonstration of how this parameter, when coupled with principles of fracture mechanics, may be used to extract meaningful calculated or estimated values for e.g.; total required volume of fracturing fluid; treating pressure; fracturing fluid viscosity; proppant size; and proppant concentration.

Abstract: A formation testing method can include interconnecting multiple pressure sensors and multiple perforating guns in a perforating string, the pressure sensors being longitudinally spaced apart along the perforating string, firing the perforating guns and the pressure sensors measuring pressure variations in a wellbore after firing the perforating guns. Another formation testing method can include interconnecting multiple pressure sensors and multiple perforating guns in a perforating string, firing the perforating guns, thereby perforating a wellbore at multiple formation intervals, each of the pressure sensors being positioned proximate a corresponding one of the formation intervals, and each pressure sensor measuring pressure variations in the wellbore proximate the corresponding interval after firing the perforating guns.

Abstract: A method for modeling flow properties over a series of time increments of a reservoir in an earth formation having a plurality of fractures is disclosed. The method includes: building a three-dimensional stress field representing stresses in the reservoir; building a three-dimensional discrete fracture network (NFM) having fracture flow properties using information obtained from a tool or changes to the stress field; running a flow simulation of the reservoir for a time increment using the NFM to model the flow properties of the reservoir for that time increment; computing a latest change in the three-dimensional stress field from the flow simulation; and incrementing the time increment and iterating the building the NFM using the latest change in the stress field, the running of the flow simulation using the latest NFM, and the computing a latest change in the stress field from the latest running of the flow simulation.

Abstract: Determining a value indicative of fracture quality. At least some of the illustrative embodiments are methods including: obtaining or measuring gas saturation of a formation to create a value indicative of pre-fracture gas saturation; and after a fracturing process measuring gas saturation of the formation to create a value indicative of post-fracture gas saturation; and creating a value indicative of fracture quality based on the value indicative of pre-fracture gas saturation and the value indicative of post-fracture gas saturation.

Abstract: Methods, systems, and apparatus for inducing fractures in a subterranean formation and more particularly methods and apparatus to place a first fracture with a first orientation in a formation followed by a second fracture with a second angular orientation in the formation are disclosed. The first and second fractures are initiated at about a fracturing location. The initiation of the first fracture is characterized by a first orientation line. The first fracture temporarily alters a stress field in the subterranean formation. The initiation of the second fracture is characterized by a second orientation line. The first orientation line and the second orientation line have an angular disposition to each other.

Abstract: Reservoir fractures are visualized using electrically active proppants to carry electric signals throughout the fracture. The electric signals are easily detected at the surface using RF antennae and a three-dimensional image of the fracture is generated.

Abstract: Methods of performing a fracture operation at a wellsite with a fracture network are provided. The methods involve obtaining wellsite data and a mechanical earth model, and generating a hydraulic fracture growth pattern for the fracture network over time. The generating involves extending hydraulic fractures from a wellbore and into the fracture network of a subterranean formation to form a hydraulic fracture network, determining hydraulic fracture parameters after the extending, determining transport parameters for proppant passing through the hydraulic fracture network, and determining fracture dimensions of the hydraulic fractures from the hydraulic fracture parameters, the transport parameters and the mechanical earth model. The methods also involve performing stress shadowing on the hydraulic fractures to determine stress interference between fractures and repeating the generating based on the determined stress interference. The methods may also involve determining crossing behavior.

Abstract: A system and method is provided for performing stimulation operations at a wellsite having a subterranean formation with a reservoir therein. The method involves acquiring integrated wellsite data (e.g., geomechanical, geological, and/or geophysical properties of the formation, and/or geometrical properties of the mechanical discontinuities in the formation). The method also involves generating a mechanical earth model using the integrated wellsite data, and identifying a crossing behavior between an induced hydraulic fracture and at least one discontinuity in the formation. The method also involves optimizing a stimulation plan to achieve an optimized crossing behavior. The stimulation plan includes at least one of fluid viscosity, rate of injection of the fracturing fluid, and concentration of a fluid loss additive. The optimization may further include adjusting the stimulation plan to achieve the optimized crossing behavior between the induced hydraulic fracture and the discontinuity in the formation.

Abstract: An apparatus having conduits, flattened tubing or pipes of varying widths, heights and/or lengths may simulate a network of fractures that may be used to experimentally evaluate the flow of treatment fluids (e.g. fracturing fluids) within narrow, shale-type fractures. The tubing or pipes each have an interior space with a height and a width, and in one non-limiting embodiment the ratio of height/width is at least 10. The conduits may be constructed of flattened tubing or constructed from components designed and engineered to have the correct height/width ratio. The apparatus may be used to empirically develop diversion principles, more precise numeric models and the parameter relationships that control fluid diversion, secondary fracture initiation and the development of complex fracture networks.

Abstract: A method for obtaining information about a hydraulic fracturing operation in a fracture zone in a well, comprises a) providing at least one acoustic sensor in the well and at least one acoustic source, b) injecting fracturing fluid into the well so as to cause fractures in a fracture zone in the surrounding formation, c) using the acoustic source to send an acoustic signal and using the acoustic receiver to receive the signal, d) repeating step c) at least once, and e) processing the received signals using a microprocessor so as to obtain information about the fractures. The source may be at the earth's surface or in a second well. Step e) may comprise measuring first-arriving acoustic waves or measuring reflected or diffracted acoustic waves. The information gained in step e) may be used to control the injection of fracturing fluid or detect out-of-zone water injection.