A flow rate control sequence for modulating the flow rate at the surface, so as to increase and/or reduce the rate of flow at specific times and increments so that the flow rate of the diverter material downhole is correspondingly reduced or increased such that it enters dominant fractures and avoids entry of marginal fractures. To achieve this, a diversion plan may be developed involving a plurality of planning stages. These stages may include a first overall planning stage, a second downhole planning stage taking into account downhole rate schedule, and the third surface planning stage taking into account parameters at the surface which may impact a diversion plan. Each of these planning stages may be updated or revised based on the results and constraints of other planning stages

Compositions and methods for the controlled delivery of acid to a desired location. In some embodiments, methods for in situ acid stimulation of a subterranean formation that contains a hydrocarbon reservoir comprise contacting the formation with an aqueous fluid that comprises (a) an ammonium salt capable of being oxidized to produce acid and (b) an oxidizing agent capable of oxidizing the ammonium salt, where the ammonium salt and oxidizing agent react to produce an acid.

An acoustic waveguide includes a body defining a resonance chamber. The body has a tubular section defining a cylindrical central portion of the chamber along a longitudinal axis. First and second end sections extend from opposite ends of the tubular section. Each end section includes an end wall tapering away from the tubular section and towards the longitudinal axis, thus defining a conoidal end portion of the chamber.

A system and a method for use of electric motors in fracturing operations are disclosed. The system includes an electric motor, a turbine generator, an encoderless vector control subsystem, and at least one pump. The turbine generator is adapted to generate electric power for the system. The encoderless vector control subsystem is coupled between the turbine generator and the electric motor to control the electric motor using determined parameters that are based in part on vibration induced in a feature associated with the turbine generator. The at least one pump is adapted to receive torque input from the electric motor.

Systems and methods for extracting desired minerals from a mineral shale zone located below the surface at an existing oil and gas drilling site using a leaching solution. The system and methods include analyzing a mineral shale zone for one or more desired mineral located at a borehole of the oil and gas wellsite, wherein the borehole was produced with horizontal drilling, and wherein the mineral shale zone includes a plurality of fissures caused by fracking. The systems and methods include pumping the leaching solution into the borehole to mobilize one or more desired materials in the mineral shale zone, extracting from the mineral shale zone the one or more desired minerals, pumping the leaching solution and the desired minerals out of the borehole, and separating the one or more desired minerals from the leaching solution.

A method for the fracking or stimulation of a hydrocarbon-bearing formation, said method comprising the steps of: providing a wellbore in need of stimulation; inserting a plug in the wellbore at a predetermined location; inserting a perforating tool and a spearhead or breakdown acid into the wellbore; positioning the tool at said predetermined location; perforating the wellbore with the tool thereby creating a perforated area; allowing the spearhead acid to come into contact with the perforated area for a predetermined period of time sufficient to prepare the formation for fracking or stimulation; removing the tool form the wellbore; and initiating the fracking of the perforated area using a fracking fluid.

Also disclosed is a corrosion inhibiting composition for us with the acid composition.

Methods, compositions, and systems that use hydrogels of graft polymers for diversion of acidic treatment fluids in subterranean formations. A method for acid diversion may comprise: applying a first acidizing treatment to a first treatment zone of a subterranean formation; introducing a hydrogel to the first treatment zone, wherein the hydrogel comprises a graft polymer that is crosslinked; and applying a second acidizing treatment to the subterranean formation, wherein the hydrogel diverts the second acidizing treatment to a second treatment zone.

A downhole tool, configured to receive a milling tool or other forcing tool, includes: a tubular mandrel; an adapter housing coupled to the mandrel; a guide sleeve disposed within the adapter housing; a movable sleeve configured for sliding movement within the guide sleeve; and a retainer positioned uphole of the movable sleeve. The retainer includes an upper annular portion, a lower annular portion, an annular void between the upper and lower annular portions, and a bridge portion extending between the upper and lower annular portions. The upper annular portion is initially fixed to the guide sleeve. The lower annular portion is configured such that downward movement of the lower annular portion causes the movable sleeve to move downward within the guide sleeve. The bridge portion comprises a through-passage and a thin walled segment adjacent to the void. Milling or otherwise disconnecting the bridge portion permits the lower annular portion to move the moveable sleeve.

Reducing leak-off during acid stimulation with dissolvable material sized to preferentially block crevices and wormholes, thus allowing the acid to travel further down the fractures, etching deeper into the reservoir than a similar process not using such dissolvable materials. After stimulation, the materials dissolve and production can proceed and will be improved over what is possible without such dissolvable materials.

A system and method for hydraulic fracturing including mixing seawater with an additive to precipitate sulfate from the seawater and mixing a flocculating agent with the seawater to agglomerate the sulfate precipitates.