Abstract: Presented is a process for use in the area of geophysical data processing, for computing a three dimensional grid of traveltimes from a three dimensional grid of velocities. The process involves a finite-difference solution to the eikonal equation in spherical coordinates, with refinements which increase the stability of the calculation and cope with numerical roundoff error as well as turned ray problems. The resulting three dimensional grid is not only useful in itself in providing information regarding the subsurface, but also can be used in depth migration, velocity analysis (especially three dimensional tomography) and in raytracing (leading to modeling of synthetic seismograms, three dimensional traveltime inversion, and map migration). This method is preferably executed on a computer, and can be performed either on a mainframe or on a massively parallel processor.

Abstract: A method for suppressing or removing coherent noise from seismic or borehole data is disclosed. The method requires horizontal alignment of the traces, comparison of the amplitude, phase and/or shape of neighboring traces, and subtraction of traces from neighboring traces only where the local correlation is high.

Abstract: A method for producing simple seismic wavelet shapes with minimal side lobe energy for use as reference signals for seismic vibrators is disclosed.

Abstract: A combination low-pressure, high-pressure hydraulic pump which allows a constant differntial pressure is disclosed. This pump features dual concentric pistons, each with its own chamber. The pistons reciprocate together at low pressures; as the system pressure increases, a spring resists the stroke of the low pressure piston, so that ultimately only the smaller, high pressure piston reciprocates.

Abstract: A downhole seismic acoustical signal source capable of selectively firing numerous, prewired explosive charges. The downhole seismic source has a firing system that uses a sequence of combinations of two conductors at a time and a downhole diode array to select and fire a single charge. The conductors are connected to a Surface Control Unit at the surface. A seismic crew on the surface can select and fire any charge through this control unit. The downhole seismic source has the ability to fire numerous explosive charges in a given downhole trip through the firing of many individual explosive charges.

Abstract: Disclosed is a process for increasing the selectivity in converting sulfates to sulfonates following ethoxylation and sulfation of alcohols. It is demonstrated that minimization of unethoxylated and monoethoxylated alcohols before the sulfation step will substantially reduce hydration to alcohols and increase the selectivity of the subsequent sulfonation step.

Abstract: A process for obtaining ethane and propane refrigerant from a lean feed gas is disclosed. Said process involves the addition of a small amount of propane to a stream of said lean feed gas, thus widening the phase envelope and increasing the ease of separation of the methane and nitrogen from heavier components.

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: 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: 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: 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: 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.