A pulsation valve system and method can include a mandrel, an oscillating valve head and a stationary valve head. The mandrel can be operably coupled to a rotor of a pulsation assembly, and can include bypass bores controlled by a spring biased piston that moves in response to a predetermined fluid pressure acting thereon. The oscillating valve head can be attached to and rotatable with the mandrel. The stationary valve head can be positioned adjacent and stationary with respect to the oscillating valve head. The stationary valve head can include a stationary valve bore defined therethrough. The oscillating valve head can include an oscillating valve bore defined therethrough that is alignable with the stationary valve bore at a predetermined rotational position. The stationary valve bore can have a radial length greater than the oscillating valve bore.

A fluid pulse generator can include a fluid motor and a bypass flow path in fluid communication with an inlet and an outlet, and a flow control device configured to permit flow through the bypass flow path in response to a predetermined pressure differential applied across the flow control device. A method of generating fluid pulses can include flowing a fluid through a fluid pulse generator, thereby generating fluid pulses, and then applying a predetermined pressure differential from an inlet to an outlet of the fluid pulse generator, thereby permitting flow of the fluid through the fluid pulse generator without generating the fluid pulses. A fluid pulse generation system can include a fluid pulse generator with a fluid motor, a variable flow restrictor, and a bypass flow path. A predetermined pressure differential applied across the fluid motor permits the flow of the fluid through the bypass flow path.

A fluid pulse generator can include a fluid motor and a bypass flow path in fluid communication with an inlet and an outlet, and a flow control device configured to permit flow through the bypass flow path in response to a predetermined pressure differential applied across the flow control device. A method of generating fluid pulses can include flowing a fluid through a fluid pulse generator, thereby generating fluid pulses, and then applying a predetermined pressure differential from an inlet to an outlet of the fluid pulse generator, thereby permitting flow of the fluid through the fluid pulse generator without generating the fluid pulses. A fluid pulse generation system can include a fluid pulse generator with a fluid motor, a variable flow restrictor, and a bypass flow path. A predetermined pressure differential applied across the fluid motor permits the flow of the fluid through the bypass flow path.

A technique facilitates controlled creation of pressure waves in a downhole environment. The technique enables creation of, for example, dynamic underbalance (DUB) pressure waves or dynamic overbalance (DOB) pressure waves which can be used to perform desired activities downhole. According to an embodiment, a pump is coupled with a pressure chamber and conveyed downhole into a borehole to a desired location. The pump may be operated downhole to change a pressure level in the pressure chamber until a sufficient pressure differential exists between an interior and an exterior of the pressure chamber. A release mechanism in communication with the pressure chamber is then rapidly opened to establish the desired pressure wave as the differing pressures equalize.

A method and a tool for sealing cracked casing cement are described. In a wellbore in which a casing is deployed, the casing and the wellbore define an annulus sealed with a casing cement. The method includes vibrating a portion of the casing cement adjacent an outer wall of the casing. The portion of the casing cement includes multiple discrete cracks. Vibrating the casing cement connects the discrete cracks to form a crack network. After vibrating the casing cement to form the crack network, a sealant is injected into the crack network through the casing. The sealant seals the crack network.

A method and a tool for sealing cracked casing cement are described. In a wellbore in which a casing is deployed, the casing and the wellbore define an annulus sealed with a casing cement. The method includes vibrating a portion of the casing cement adjacent an outer wall of the casing. The portion of the casing cement includes multiple discrete cracks. Vibrating the casing cement connects the discrete cracks to form a crack network. After vibrating the casing cement to form the crack network, a sealant is injected into the crack network through the casing. The sealant seals the crack network.

A tunable wellbore pulsation valve reduces drillstring friction in a wellbore. An upper valve plate and a lower valve plate, and upper valve plate orifice and lower valve plate orifice enabling throughflow. A Moineau motor rotates the upper valve plate while the lower valve plate remains stationary. Fluid flow causes a first fluid state of fluid passing through both the upper valve plate and the lower valve plate when the fluid passing causes rotation of the upper valve plate to align the upper valve plate orifice with the lower valve plate orifice. Increased flow efficiency produces more powerful fluid pressure pulsations and axial vibrations without increasing pump pressure at the surface of the wellbore, yielding increased wellbore friction reduction while expending the same or less energy at the surface pump than would be expended in the absence of the reduced turbulent and shear conditions and increased laminar conditions.

A tunable wellbore pulsation valve reduces drillstring friction in a wellbore. An upper valve plate and a lower valve plate, and upper valve plate orifice and lower valve plate orifice enabling throughflow. A Moineau motor rotates the upper valve plate while the lower valve plate remains stationary. Fluid flow causes a first fluid state of fluid passing through both the upper valve plate and the lower valve plate when the fluid passing causes rotation of the upper valve plate to align the upper valve plate orifice with the lower valve plate orifice. Increased flow efficiency produces more powerful fluid pressure pulsations and axial vibrations without increasing pump pressure at the surface of the wellbore, yielding increased wellbore friction reduction while expending the same or less energy at the surface pump than would be expended in the absence of the reduced turbulent and shear conditions and increased laminar conditions.

A waveform energy generation system, the system including at least one joint of production casing, and one or more energy generators residing along the joint of production casing. The energy generators are configured to be in substantial mechanical contact with a subsurface formation within a wellbore. The energy generators may include either explosive devices or a piezo-electric material. The system also includes a signal transmission system. The signal transmission system is used to send control signals from the surface down to the energy generators for activation at the formation's resonant frequency. Methods of enhancing the permeability of a rock matrix within a subsurface formation using the wellbore as an energy generator are also provided.

Systems and methods for improving injectivity of a hydrocarbon reservoir include: identifying a restriction of flow from an injection well into the hydrocarbon reservoir; transmitting a series of acoustic waves from an injection well into a formation that includes the hydrocarbon reservoir, wherein the series of acoustic waves are transmitted continuously for at least one day; transmitting a series of seismic waves from the injection well into the formation after the series of acoustic waves are transmitted into the hydrocarbon reservoir, wherein the series of seismic waves are transmitted continuously for at least one week; and injecting water into the injection well to cause hydrocarbon of the hydrocarbon reservoir to flow from the hydrocarbon reservoir to a production well after the series of acoustic waves are transmitted into the hydrocarbon reservoir.