Abstract: Disclosed are compositions and related methods of use for reducing the viscosity of a fluid introduced into a subterranean formation. The compositions are introduced into the subterranean formation and are non-reactive to the fluid until activated by the closing of any fractures in the subterranean formation upon the compositions. The compositions are comprised of a viscosity reducing chemical, such as an enzyme, oxidizing agent, acid, catalyst, or mixtures thereof, encapsulated in dry or liquid form within hollow or porous, crushable beads. The beads can be formed from glass, ceramics, plastics, gels, or mixtures thereof.

Abstract: To control adverse vertical height growth of the fracture created during hydraulic fracturing treatments of subterranean formations, a nonproppant fluid stage is injected during the treatment. The nonproppant stage comprises a transport fluid and a flow block material. The flow block material can be any particulate used as a fracture proppant, and has a particle size distribution which is sufficient to form a substantially impermeable barrier to fluid flow into the vertical extremities of the fracture. The particle size distribution preferably comprises at least two different particles sizes.

Abstract: This invention concerns an impact wrench for breaking a threaded connection between a first section of pipe and a second section of pipe. It includes an arcuate gripping member having an exterior gripping means for gripping the inside of the first section of pipe and an impact tool for directing multiple sudden distinct forces of torque through said gripping means to the first section. It also includes a second arcuate gripping member for gripping the interior of the second section of pipe which is connected to the first and means for the second arcuate gripping member to receive the reaction torque from the impact tool.

Abstract: An improved method of oil recovery for use within an underground formation having an ion exchange capacity. An aqueous micellar fluid bank containing a surfactant is injected into the formation followed by an injection of the bank with a mobility control fluid, such as a polymer-thickened aqueous solution, into the formation. The mobility control fluid has a salt level lower than or equal to the salt level of the micellar fluid, but a greater divalent cation-to-monovalent cation ratio than the micellar fluid make-up brine, preconditioning brine or original in-place brine in a reservoir in order to reduce the hardness of the formation fluids in situ generated at the trailing edge of the micellar fluid which in turn reduces the surfactant loss from the micellar fluid.

Abstract: This relates to a pressure coring tool to obtain pressurized samples of the formation through which the wellbore is drilled. It includes a housing which supports a guide means along which the drill bit, core barrel and motor can be moved to extend or retract the cutting bit and core barrel along a selected path which preferably is horizontal. The core barrel is retracted inwardly on a horizontal path and tilted in an upward position such as the outer end of the core barrel is higher than the end near the barrel. Means are provided to pressure seal the cut core within the core barrel.

Abstract: Method and apparatus for making a sharp separation of solids into components which are finer than the screen mesh and coarser then the screen mesh. The solids ladened fluid is introduced onto a screen to separate coarse solids from fine solids. A tray containing a body of aqueous liquid is vibrated causing the aqueous liquid to repeatedly contact the solids while on the screen to provide the needed mobility for fine particles to pass through the screen with the liquid. The aqueous liquid returns to the tray and the vibration of the tray aids in removal of the fine solids which have passed through the screen from the tray. Aqueous liquid is continuously added to the tray or sprayed above the screen to keep accumulated solids from increasing the viscosity of the aqueous liquid in the tray.

Abstract: A sonic transmitter and receiver are employed to locate and evaluate zones of significant porosity in the proximity of a borehole. Continuous wave and pulse techniques are used to locate the zones and to determine the void dimensions by means of frequency domain signatures. Both through-transmission and reflection methods are employed. The technique is considered especially useful for locating fluid-filled vugular zones.

Abstract: An apparatus for testing the functioning of a float-activated liquid level control device comprises a float for activating a liquid level control device, a float cage enclosing said float, an entry port accessible from outside a separating tank through which fluid may be input directly into the float cage enclosure, and a flange connection for mounting the test apparatus inside a fluid separation tank. The method comprises connecting a fluid source to the input port of the apparatus of the instant invention, injecting fluid directly into the float cage enclosure to activate the float of the instant invention, monitoring the liquid level control device to insure that it is functioning correctly and then withdrawing the input fluid to return the float to its normal operating position.

Abstract: In the displacement of crude oil through a subterranean reservoir with an aqueous displacement fluid, improved oil recovery is obtained by providing a salinity contrast between the displacement fluid and aqueous formation fluid. The salinity of the displacement fluid is selected such that at least one mixture of the aqueous displacement and the aqueous formation fluid will have the minimum interfacial tension between the displaced crude oil and mixtures of these fluids. The minimum interfacial tension between crude oil and mixtures of aqueous displacement and formation fluids can be determined by mixing these fluids such that some mixtures contain from essentially none to essentially all displacement fluid and determining the interfacial tension between the mixtures and the crude oil. The displacement fluid is a micellar fluid followed by a polymer-containing aqueous fluid.

Abstract: An apparatus is described whereby the side force on a drill bit can be measured during drilling operations and transmitted to the surface where it can be used in predicting trajectory of the hole and taking corrective action in the drilling operation. A downhole assembly using a downhole motor is modified to include means to detect the side thrust or force on a bit driven by the motor and the force on the deflection means of the downhole motor. These measured forces are transmitted to the surface of the earth during drilling operations and are used in evaluating and controlling drilling operations. Means are also provided to measure magnitude of the force on a downhole stabilizer.

Abstract: A method is disclosed for fracturing a subterranean formation penetrated by a wellbore, the fracturing being accomplished by first injecting into said formation a low leakoff, high efficiency fluid followed by a controlled viscosity fluid carrying propping agents.

Abstract: A diverter tool and method of use thereof for use in setting a cement plug in a well. The tool comprises a hollow cylindrical body provided with a plurality cylindrical ports, the axes of which form a plane essentially perpendicular to the axis of the tool.

Abstract: For enhanced recovery of petroleum, particularly for recovery of residual oil during conventional water-flooding, an aqueous solution of peroxide is injected into an oil-bearing formation. The concentration of peroxide in the aqueous solution ranges from about 0.1 to about 3.0 weight percent, and injection of peroxide need not be followed or accompanied by injection of alkaline solution. The aqueous peroxide solution may then be displaced toward the producing well or wells to sweep out residual oil.

Abstract: A method of controlled thermal linking of an injection well and a production well, both penetrating an underground formation, accomplished by injecting oxidant into the annulus of the injection well and fuel into the tubing of an injection well in stoichiometric proportions, and initiating a combustion zone at the production well which propagates along a predictable path in the formation which is a deviated or horizontal portion of the injection well.

Abstract: During fracture treatment of a subterranean formation, multiple hydraulic fracturing cycles are performed wherein the bottomhole treating pressure of a wellbore is controlled to not exceed a maximum bottomhole treating pressure for the formation, thereby attaining maximum principle fracture extension and limiting initiation of secondary fractures transverse to the principle fracture extension.

Abstract: Any method for tertiary recovery of oil from an oil reservoir penetrated by injection and producing wells in which injected fluid, either the micellar or polymer bank, is formulated so that the front portion of the bank is miscible with oil and the rear portion is miscible with water. In one method of formulating the graded bank or banks, the salinity of the bank is graded from a high salinity at the front to a low salinity at the rear. Another method of formulating the bank, the cosurfactant concentration is graded from a low cosurfactant concentration at the front of the bank to a low concentration of surfactant at the rear.

Abstract: Highly conductive zones of subterranean formations are treated with aqueous fluids containing gel-forming amounts of water-soluble basic lignins. Suitable treating fluids contain about 2 to about 8 wt. % sodium hydroxide solution. The lignin solutions gel within the formation due to reactivity with oil-water and/or the rock matrix. Alternately, following the injection of the gel-forming fluids, acidic gas is injected to cause gel formation.

Abstract: Specification discloses a process for completing a wellbore into a subterranean reservoir. In completing the wellbore, a completion fluid is pumped into the wellbore casing to displace the mud contained therein, the improvement comprising pumping a spacer system into the wellbore casing before pumping the completion fluid into the wellbore. The spacer system comprises a spacer fluid having a viscosity sufficiently high such that the spacer fluid exists in either laminar or plug flow at normal circulation rates.

Abstract: A method of flow testing a producing formation through a well including lowering into the well a recording pressure and temperature device to measure pressure and temperature as functions of time, then lowering into the well a test chamber closed at the bottom by a surface activated valve. The space between the chamber and the top of the formation is sealed and immediately thereafter the pressure and temperature of the well is measured. The valve on the test chamber is opened to allow formation fluids to enter therein and the pressure and temperature is measured as a function of time for a substantial period of time during which the pressure in the chamber increases, whereby the flow capacity and skin factor of the formation can be calculated.

Abstract: This is a special downhole multi-layer sand screen for oil and other fluids containing sand. The preferred embodiment of the sand filter includes an outer screen, an intermediate screen and an inner screen although another embodiment may have only an outer and an inner screen. The outermost screen is of larger spacing to retain only the coarser sand particles and the openings in the inner two screens are progressively smaller to retain the less coarse sand material. The coarser sand particles bridge about the larger openings in the outer screens and progressively finer sand materials bridge across the intermediate and inner screens.