Abstract: A process for welding mechanically and/or thermally treated alloy pipes to achieve the full tensile capacity of the unwelded base alloy across the welded pipe joint is disclosed. The process comprises welding the pipes together at the beveled pipe ends to form a cap of weld metal. The weld metal cap overlaps that portion of the heat-affected zone which is created in the base alloy adjacent to the bevel of each pipe during welding. To further increase the tensile capacity of the welded joint, a low-heat buffer bead layer can be deposited on the outer surface of each pipe proximate the outer edge of each bevel, prior to depositing the weld metal between the bevels. The buffer bead layers serve to reduce the thickness of that portion of the heat-affected zone which is formed in the base alloy under each toe of the weld metal cap (upon formation of the weld metal cap) to a level having no significant reduction in the overall tensile capacity of the welded joint.

Abstract: A method for determining residual oil saturation of a watered-out reservoir using two water soluble tracers having different partition coefficients in oil. The partitioning tracers are selected from the group consisting of tritiated or carbon 14 tagged alcohols, ketones, aldehydes, water and oil insoluble inorganics and organic radioactive isotopes. The tracers are injected into the formation, and their production curves are analyzed over a period of time to determine chromatographic separation of the tracers.

Abstract: Methods are disclosed for multi-stage tests of material samples, including but not limited to rock and shale samples, the methods, in one aspect, including the steps of placing a load on the sample, while under a constant confining pressure the sample mounted in a triaxial test apparatus; measuring and recording sample pore pressure continuously during the test; removing the load on the sample; changing confining pressure on the sample; permitting the sample's pore pressure to equilibrate at a new pore pressure with the new confining pressure; permitting the sample to drain fluid to an equilibrium value and placing a new load on the sample measuring and recording resulting pressure and load. In one embodiment these steps are repeated a plurality of times and a plurality of pore pressure, confining pressure, and load readings are obtained.

Abstract: A data collection and transmission system for gathering high count vertical seismic data is disclosed using a sequence of vertically aligned seismic receivers, the analog outputs from which are sequentially analog sampled and time multiplexed onto a common pair of data conductors in the support and transmission cable. The data is time demultiplexed at the surface and appears substantially as digital data because of the relatively short sampling times. Such data is converted into analog data with conventional digital-to-analog converter means.A clock signal activates counters for establishing non-overlapping data gates in the respective sondes, the operation of the gates supplying the cable with the respective receiver analog signals in a sequence from bottom to top, simultaneously switching off previously gated signals until a clock reset pulse resets the entire sonde string.

Abstract: A water-based fluid for use in the drilling of wells is disclosed. This fluid: is rheologically stable over a wide temperature range, from room temperature to at least about 475.degree. F., thus reducing drilling time in high temperature applications; typically necessitates minimal disposal rates in operation; is resistant to temperature-induced carbonate gellation; creates a thin filter cake; and combines the low toxicity of a water-based fluid with the performance stability of an oil-based fluid.As further disclosed herein, this drilling fluid comprises a water-based colloidal suspension of certain readily available drilling fluid components, including clay, an inorganic salt, and parenchymal cell cellulose ("PCC").

Abstract: Methods and apparatuses are disclosed for determining a three factor envelope for the material of a preserved core sample. The three factors are ultrasonic velocity through the material, mean effective stress and an elastoplastic property of the material. Values are obtained, in one aspect of the invention, by applying a confining pressure to the material; measuring the material's pore pressure and the ultrasonic velocity therethrough; calculating the material's mean effective stress for that confining pressure; and then loading the sample to near shear failure to measure the value of the elastoplastic property. At different confining pressures the measurements are repeated on the same sample to obtain values for the mean effective stress and elastoplastic property at each level. The envelope is determined by graphically representing the data obtained.

Abstract: The mispositioning of reflectors in a velocity analysis enhanced common-offset time migrated image is corrected by carrying out inverse migration on the time image, followed by zero-offset depth migration.

Abstract: A downhole seismic source for producing seismic waves in the 0.2-5 KHz frequency with a bandwidth of between 5 and 50 Hz is formed from a magnetostrictive bar with undamped end weights.

Abstract: A method and apparatus whereby recovery from heavy oil and bitumen reservoirs may be increased over that achieved in the later stages of cyclic steam stimulation (CSS) operations. Two sets of perforations perforate a steam chamber in a reservoir surrounding a well. The two sets of perforations are isolated hydraulically from each other within the casing by a thermal packer. Steam is then injected down the casing annulus into the upper set of perforations. After a period of steam injection, steam injection is halted and hydrocarbons are produced from the lower set of perforations through one of two strings of tubing extending through the thermal packer. The second string of tubing serves to vent the well during production. This process may be repeated over the life of the well, alternately injecting steam and producing hydrocarbons.

Abstract: Methods and apparatuses for quantitatively measuring the strengths, pore pressures, and mechanical properties of low permeability geologic materials, such as shales, including test specimen preparation apparatus for adjusting test specimen water content and test apparatus with an end cap having a pore pressure transducer channel disposed adjacent a test specimen filled with an immiscible, inert fluid which does not wet the test specimen, and controlling the deviatoric load on the test specimen during the test to prevent premature failure.

Abstract: An apparatus and method for moving heavy machinery in a confined space, particularly suited for installing or removing engine oil pumps from production equipment. The apparatus is formed from a bracket to be attached to the equipment to be moved; this bracket is pivotally attached to a first arm, which controls pivoting of the bracket face and pivotally attached to a second arm, which furnishes support. The arms are connected to each other such that the first arm and the second arm may pivot in parallel planes. The apparatus includes a frame for attaching the second arm to a support. Where the frame has the shape of an upside down "L" the support may overlie the workpiece.

Abstract: Threaded pipe sections are connected to form a casing joint having proper sealing positioning at proper makeup torque. This improved connection includes a first pipe section having a standard API triangle mark at a predetermined position on its exterior surface for the proper axial engagement of the pin member with the coupling or box member. The box member is plated with a metal substantially comprising tin. A thread lubricant containing Teflon.TM. is applied to the threads of the pin and/or the threads of the box. The pin member and the box member are helically rotated together up to a minimum of an empirically predetermined torque range. While inexpensive, this improvement provides a simple method to determine visually on the rig floor, or at the pipe rack, whether the joint is properly made up to thereby provide effective gas sealing of the API buttress tapered threaded joint.

Abstract: An apparatus and method for detecting seismic waves traveling in an underground formation. The apparatus includes a hydraulic pressure source, preferably a downhole hydraulic pump; a plurality of small, light-weight, flexibly connected clamping detector units having hydraulically actuated clamps; conduit means connecting the hydraulic pressure source to the detector units so that the detector units may be hydraulically clamped to a wellbore with a large force by activation of the clamps; and means for conditioning signals from the detectors. The small, light-weight detector units are securely clamped to the side of the wellbore because of the high clamping force-to-weight ratio thereby allowing high frequency signals to be detected without interference.

Abstract: A method for determining drilling fluid density for stabilizing a wellbore including obtaining shale cuttings from a wellbore. In one embodiment of a method according to this invention, shale cuttings are obtained from a wellbore and their index properties, including but not limited to surface area, is measured; mean effective stress around the wellbore is calculated using the geostatic overburden in situ stress, the field pore pressure, and the total stress around the wellbore; the in situ shale strength is determined using a correlation between surface area, mean effective stress and shale strength; and drilling fluid density is determined using the shale strength. Methods for determining in situ shale strengths, elastic properties, pore pressures, and formation stresses of low permeability rocks.

Abstract: A method for estimating pore fluid pressure in a subterranean formation is disclosed for use in drilling wells. A pair of velocity-effective stress relations are used to compute pore fluid pressure from velocity data. One relation applies when the current effective stress is the highest ever experienced by the subterranean formation. The second relation accounts for hysteresis effects when the effective stress has been reduced. Pore fluid pressure is found by subtracting the computed effective stress from an estimate of the overburden stress.

Abstract: A nontoxic, nonchloride, water-base drilling fluid which stabilizes water sensitive shales is disclosed. This drilling fluid is comprised of the potassium or ammonium salt of an organic acid in combination with a polar organic liquid, so as to reduce shale swelling with mineral adverse impact on the environment.

Abstract: Disclosed is a seismic surveying and data processing method to filter from seismic data any energy contributions that are not in the seismic line of profile. The surveying method requires a receiver geometry wherein at least one receiver is in and at least one receiver is out of the line of profile, so that in common offset gather or shot record plots, seismic events along the line of profile are aligned in time and out-of-plane energy takes the form of a series of sawtoothed seismic events arriving at different times in the different lines of receivers. Knowing the number of out-of-plane energies and their respective dips allows for the design of a filter, which is applied to the data with a computer, to null and thereby remove the effects of unwanted out-of-plane energy from the seismic survey data.

Abstract: A water-based fluid for use in the drilling of wells is disclosed. This fluid: is rheologically stable over a wide temperature range, from room temperature to at least about 475.degree. F., thus reducing drilling time in high temperature applications; typically necessitates minimal disposal rates in operation; is resistant to temperature-induced carbonate gellation; creates a thin filter cake; and combines the low toxicity of a water-based fluid with the performance stability of an oil-based fluid.As further disclosed herein, this drilling fluid comprises a water-based colloidal suspension of certain readily available drilling fluid components, including clay, parenchymal cell cellulose ("PCC") and an inorganic salt.

Abstract: A process for removing diamondoids from a stream of natural gas. In this process, contact between a solvent liquid and natural gas containing diamondoids occurs in a stepwise counter current cascaded fashion. The stepwise counter-current cascaded arrangement substantially improves the removal of the light diamondoids (adamantane). The contacting (mixing) of the gas and solvent liquid allows the liquid to absorb the diamondoids contained in the gas. The gas and liquid are then separated thereby removing the diamondoids from the gas. In the preferred embodiment, a multi -staged trayed solvent contractor tower is used to facilitate the stepwise counter current cascaded contacting in the gas production process immediately after the separation of the gas from any liquid in the gas. The partially saturated diamondoid liquid solvent from the tower can also be mixed with the gas at a point before the separation of the gas from any reservoir formation liquid in order to enhance the diamondoid removal process.

Abstract: An improvement to a centralizer that may reduce the torque required to rotate a casing in a borehole during primary cementing is disclosed. In a first embodiment, the improvement is adapted to a bow spring type centralizer having intermediate fixed and slidable sleeves with each sleeve circumscribed by an end band. The end bands are connected to each other by a plurality of bow springs. The improvement includes interposing a sleeve bearing between each end band and its respective intermediate sleeve. The sleeve bearings may be attached to the intermediate sleeves to permit their rotation with the casing relative to the stationary end bands and bow springs. Alternatively, the intermediate sleeves may be eliminated and the sleeve bearings interposed directly between the outer surface of the casing and inner surfaces of their respective end bands.