Abstract: A measuring while drilling apparatus for use in the drilling of subterranean wells comprises a plurality of interconnected tubular housings which are insertable into and removable from a drill string by a wire line. A hollow plunger on the bottom of the apparatus is vertically shiftable with respect to a fixed diameter orifice disposed in the path of the drilling fluid flow. Fluid pressure forces derived from the drilling fluid effect the movement of the plunger forward and away from the orifice to create pressure pulses which are transmittable through the drilling fluid to the surface. Sensors provided in the housings generate signals, which are converted by a downhole controller, to effect the sequential generation of the positive pressure pulses to be indicated at the surface of the well by a digital readout of the outputs of the various sensors carried in the tubular housings.

Abstract: A modified subterranean antenna structure for use in boreholes that pivotally balances a separate core member within the hollow interior of a fixed winding member in order to filter out mechanically induced vibrations from the core. The mechanical natural resonant frequency of the core is reduced and becomes less than the lowest electromagnetic signal frequency intended to be transmitted to and received by the subterranean antenna. In this way, mechanically induced vibrations will not create mechanically generated frequency signals sympathetic to the frequencies chosen for the antenna communication band frequencies.

Abstract: An apparatus employing a set of inductive coils to transmit AC data and power signals between a downhole apparatus (which may include a sensor and a safety valve) and apparatus at the surface of the earth. In a preferred embodiment, the invention inductively couples a low frequency (less than 3 KHz) AC power signal from an outer wellhead coupler coil to an inner wellhead coupler coil wound around a tubing string. The AC signal propagates down a wireline conductor along the tubing string to a first downhole coupler coil (also wound around the tubing string) and is inductively coupled from the first downhole coupler coil to a second downhole coupler coil within the tubing. The power signal is preferably rectified, and then employed to power various items of downhole equipment. Data from a downhole sensor (whose frequency is preferably in the range from about 1.0 KHz to about 1.5 KHz) is impressed on the second downhole coil to modulate the AC power signal.

Abstract: A modified subterranean antenna structure for use in boreholes that pivotally balances a separate core member within the hollow interior of a fixed winding member in order to filter out mechanically induced vibrations from the core. The mechanical natural resonant frequency of the core is reduced and becomes less than the lowest electromagnetic signal frequency intended to be transmitted to and received by the subterranean antenna. In this way, mechanically induced vibrations will not create mechanically generated frequency signals sympathetic to the frequencies chosen for the antenna communication band frequencies.

Abstract: An elastomeric body encapsulates an electronic assembly, to be protected from vibration on shock, and is confined in a closed cavity of a structure subject to the vibration and shock. The body is cast in a separate mold having a cavity corresponding in shape and size to the closed cavity. The surface of the mold has projections to form indentations in the surface of the body. With the body in the closed cavities, the indentations are effectively voids and accept elastomeric material displaced from the body when the body expands relative to the cavity.The preferred embodiment provides a strongback support with open cavities, each to receive a body. The strongback is inserted into a tube to complete the structure and close the open cavities. The strongback has wiring chambers to accept flexible leads connected to each body, and channels into which wire is potted, to extend from the leads to external circuitry.

Abstract: A method and apparatus for stabilizing a communication sensor in a borehole is described. The principle embodiment described includes a pair of centralizers at opposite ends of the housing for the communication sensor to maintain each of such respective ends at a constant lateral displacement from the borehole casing. A pair of flexible joints are provided to isolate the communication sensor to decouple the component to be protected from any motion and/or forces secured to the same urging it from the centralized position.

Abstract: A system for verifying the effectiveness of electromagnetic signal control of a subsurface safety valve installed in a well. Signals are transmitted from a surface station to actuate the subsurface installed valve. Signals received at the valve are decoded and information relating to them is stored. A sensor detects actual valve actuation and provides signals indicative thereof which are also stored. After the valve is removed from its downhole installation, the stored signals are read, and the data indicated thereby is compared with data recorded at the time of signal transmission from the surface.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well. Anchor means on the sensing means prevents it from rotating relative to the sleeve.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well. Anchor means on the sensing means prevents it from rotating relative to the sleeve.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Abstract: In response to a signal to open and close a solenoid-operated valve, which is urged closed by flow of fluid through it, a circuit supplies a large current to the solenoid to open the valve, reduces the current to hold the valve open, and interrupts the current to close the valve. The circuit provides high electrical efficiency during operation. One embodiment of the invention is particularly suitable for use in systems in which the voltage of the power source varies over a wide range.

Abstract: The accuracy of well logging data transmitted from a downhole location to the surface of the earth is verified by generating the data at the downhole location, storing the data in a subsurface assembly in the well, transmitting signals corresponding to the data to the surface through a first transmission system while keeping the data stored in the subsurface assembly, and recording the signals transmitted to the surface through the first transmission system. Thereafter, the subsurface assembly is transferred to the surface, and signals corresponding to the stored data are transmitted through a second transmission system from the assembly to an electronic processing system. The signals transmitted through the second transmission system are then compared with the signals transmitted through the first system.