805 results about "Measurement while drilling" patented technology

A system and method are provided for providing electromagnetic (EM) measurement-while-drilling (MWD) telemetry capabilities using an existing mud-pulse MWD tool. An EM tool intercepts the output from the mud-pulse tool and generates an EM signal that mimics a mud-pulse pressure signal. The EM signal is intercepted at the surface by a receiver module that conditions the signal and inputs the signal into the existing pulse tool receiver. Since the EM signal mimics a mud-pulse signal, the pulse tool receiver does not require software or hardware modifications in order to process an EM telemetry mode. The EM tool can be adapted to also provide dual telemetry by incorporating a conventional pressure pulser that would normally be used with the pulse tool. A gap sub assembly for isolating the drill string is also provided that includes a pair of subs whose shoulders are separated by a non-conductive ceramic material and whose threads are separated by an insulative material, preferably a Kevlar™ cloth.

Subsurface wellbore conditions are measured directly in the wellbore while the fluid circulation system is not pumping. The measured values are recorded at the subsurface location and subsequently transmitted to the well surface when circulation is resumed using fluid pulse telemetry (FPT). Real-time measurements made when the fluids are circulating are transmitted real time using FPT. Axially spaced measurements are used to obtain differential values. The apparatus of the invention comprises an assembly carried by a drill string that is used to selectively isolate the area within the well that is to be evaluated. The apparatus includes an assembly having axially spaced inflatable well packers that are used to isolate an uncased section of the wellbore. The apparatus is equipped with self-contained measuring and recording equipment, a fluid receiving reservoir, circulation valving, measurement while drilling equipment, and automated controls. Measurements are made while the circulation is terminated or while the well packers are being used to isolate an area of the wellbore from the circulating fluid. The method is used to directly measure and evaluate conditions caused by pumping and drill string movement, such as swab and surge pressures. Other conditions such as the formation strength, formation pressure, the fluid density, and other subsurface conditions related to the well are also measured.

A method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a bore hole is described. A novel pressure pulse generator or “pulser” is coupled to a sensor package, a controller and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled. The assembled apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.

A measurement-while-drilling or logging while drilling method and apparatus for determining the azimuth of providing magnetic field in a remote formation layer in the vicinity of a down hole resistivity tool. A cross-component magnetic field with substantially orthogonal transmitter and receiver coils is provided. The coil planes are either substantially orthogonal (coaxial coils) or parallel (transverse coils) with respect to, the longitudinal axis of the tool body. The coils are placed on the tool body having a external surface and a plurality of grooves are cut in the external surface of the tool body and oriented substantially horizontally with respect to the longitudinal axis of the tool body for the coils and oriented vertically with respect to the longitudinal axis of the tool body for the coaxial coils. A transverse and coaxial coil are placed in the grooves for transmission or reception of a cross-component transverse magnetic field. Ferrite materials may be inserted in the grooves in between the coil wire and the bottom of the grooves. Multiple receivers, transmitters and frequencies may be used to obtain the maximum possible signal-to-noise ratio. The in-phase or quadrature part of a magnetic field, or a combination of the two, or alternatively, the amplitude and / or phase, of the cross-component magnetic field may be measured and processed to indicate the azimuth of a remote layer boundary, provided that the layer boundary is within the depth of investigation of the tool. Measurements may also be made at continuous or multiple tool azimuths.