Accumulator recharging valve

Angular whipstock alignment means

Apparatus for measuring the weight of the drill string

Apparatus for placement and retrieval of downhole gauges

Apparatus for setting and orienting a whipstock in a well condui

Bottom hole fluid pressure communicating probe and locking mandr

Chemical actuation of downhole tools

Continuous brine leakage monitoring system for a production oil

Coupon holder for corrosion test downhole in a borehole

Deflate-equalizing valve apparatus for inflatable packer formati

Downhole coupon holder

Dual packer apparatus and method

Gauge carrier

Gauge carrier

Hydraulic circuit for borehole telemetry apparatus

Hydraulic power unit for measurement while drilling apparatus

Internal protection of well casing

Measuring and transmitting apparatus for use in a drill string

Monitoring well

Mounting and shock absorber assembly for borehole telemetry appa