A bit saver assembly having an inner valve sleeve that actuates upon the weight-on-bit (WOB) of the drill bit exceeding a threshold value to overcome the countervailing force provided by a spring contained within the bit saver assembly and the internal flow pressure of the drilling fluid at the area of the inner valve sleeve. Actuation of the inner valve sleeve opens a fluid passage to the wellbore annulus resulting in a reduction of drilling fluid flow pressure and the stretch of the drill string thereby reducing WOB of the drill bit without operator assistance.

Apparatus and methods for performing subsea drilling operations. An example method may include receiving drilling fluid from a drilling fluid source at a first pressure by a pressure exchanger located within a subsea environment and receiving seawater from the subsea environment at a second pressure by the pressure exchanger to increase pressure of the drilling fluid within the pressure exchanger to a third pressure. The second and third pressures are substantially greater than the first pressure. The method may further include discharging the drilling fluid from the pressure exchanger into piping to communicate the drilling fluid to a drill forming a wellbore in a seabed and discharging the seawater from the pressure exchanger into the subsea environment.

Methods and systems for the treatment of wells are disclosed. A method for treating a well comprises providing a treatment fluid comprising calcium-aluminate cement, water, and a cement set retarder; and introducing the treatment fluid into a wellbore. A system for treating a well comprises a treatment fluid comprising calcium-aluminate cement, water, and a cement set retarder; a vessel to contain the treatment fluid; a pumping system coupled to the vessel to pump the treatment fluid; and a conduit coupled to the pumping system.

Systems and methods for formation characterization in a subterranean formation are disclosed. A set of microelectromechanical system (MEMS) devices may be disposed in a circulating fluid. Each MEMS device in the set may have a machine-scannable designator. A MEMS scanner may be configured to scan the designator of a MEMS device in response to circulation of the circulating fluid in a wellbore surrounded by the formation. A MEMS analysis subsystem communicatively coupled with the MEMS scanner may store the designator of each MEMS device in the set, detect a subset of MEMS devices by receiving the designators of MEMS devices from the MEMS scanner, and determine a characteristic of the formation based on the subset of MEMS devices.

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 from the wellbore; and initiating the fracking of the perforated area using a fracking fluid. Also disclosed is a corrosion inhibiting composition for use with the acid composition.

Systems and methods for an integrated wellbore stress, stability and strengthening analysis are disclosed. An integrated geomechanical tool can be used to analyze and evaluate stress along the length of the wellbore to identify a safe drilling mud weight window and help identify troublesome zones in the wellbore. Fracture length may then be predicted in the identified troublesome zones by using a stress tensor calculated during the stress analysis. The calculated fracture length may be used to perform a strengthening analysis. After performing strengthening analysis, mud loss may be predicted based on predicted fracture size calculated during the stress, stability and strengthening analyzes.

Embodiments disclosed relate to a composition and a method of treating a formation. The method includes introducing a loss circulation material system through a wellbore into a formation, where the loss circulation material system is comprised of an esterified derivative of an epoxidized organic material and a curing agent. The esterified derivative of an epoxidized organic material has a formula of: ##STR00001##
where R′ comprises H, a substituted or an unsubstituted (C1-C12) hydrocarbyl group; and where R″ comprises a substituted or an unsubstituted (C2-C30) hydrocarbyl group, including where at least one oxygen atom is attached to two different adjacent carbon atoms of the (C2-C30) hydrocarbyl group. The method also includes maintaining wellbore conditions such that the loss circulation material system cures into a loss circulation material in the formation. The cured loss circulation material may withstand a pressure differential up to about 20,000 psid.

The instant invention relates to a method for sealing a subterranean environment, wherein a polyurethane encapsulated polyamine is injected into the subterranean environment and is released in situ in the presence of a reactive species able to form a gel or a precipitate by a physical association and/or a chemical reaction with the released polyamine.

A system includes a mud return system. The mud return system includes a pressure exchanger (PX) configured to be installed in a body of water, to receive used drilling mud, to receive a second fluid, to utilize the second fluid to pressurize the drilling mud for transport, via a mud return line, from a first location at or near the sea floor to a second location at or near a surface of the body of water.

Disclosed are compositions and kits of fibers and acid-functional vinyl alcohol polymers, wherein such compositions and kits are useful for wellbore remediation as applied to a subterranean formation traversed by the borehole of an oil or gas well.