Exxon Production Research Company

Mark A Miller

Sen-Tsuen Chen

Christine E Krohn

Jing-Yau Chung

John T Evans

Erik A Eriksen

James D Fox

James C Wainerdi

Thomas J Murray, Jr

J Dave Fox

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.

Downhole pump of constant differential hydraulic pressure

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.

Simple multishot downhole explosive tool

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.

Apparatus and method for detecting seismic waves in a borehole using

A downhole seismic acoustical signal source capable of selectively firing numerous, prewired explosive charges. The downhole seismic source uses a self-contained firing circuit that is capable of receiving select and fire signals from a seismic crew at the ground surface through a standard seven conductor wireline cable to detonate the explosive charges. The downhole seismic source is capable of generating numerous signals in a given downhole trip through the firing of many individual explosive charges.

Multishot downhole explosive device as a seismic source

Method and apparatus for acoustic wave generation and transmission into a subsurface earth formation. A logging sonde adapted to be suspended in a borehole within the formation houses a generator means for simultaneously generating a plurality of acoustic waves traveling in the direction of and spaced substantially evenly about the logitudinal axis of the sonde. An acoustic energy reflector means within the housing reflects the waves radially outwards of the axis and into the formation at angles generally perpendicular to the axis. Detectors within the housing spaced longitudinally from the generator and reflector detect acoustic energy in the formation resulting from the reflected waves. In a preferred embodiment, the generator means comprises four cylindrical magnetostrictively energized elements disposed about the central axis of the sonde, each having an axis parallel to the central axis, so that the four axes of the elements, when viewed in the direction of the central axis, define four corners of a square. The elements are designed so that upon energization, a given element vibrates longitudinally out of phase relative to the two elements adjacent thereto, vibration of the four elements in concert generating two positive and two negative waves which, when reflected into the formation, interfere to produce a quadrupole shear wave.

Growing community of inventors

Houston, TX, United States of America

Mark A Miller