The desirability and effectiveness of well logging systems (also known as measurement-while drilling systems) where information is sensed in the well hole and transmitted to the surface. In one example, mud pulse telemetry systems provide the operator at the surface with means for quickly determining various kinds of downhole information, most particularly information about the location, orientation and direction of the drill string at the bottom of the well in a directional drilling operation. During normal drilling operations, a continuous column of mud is circulating within the drill string from the surface of the well to the drilling bit at the bottom of the well and then back to the surface.
Mud pulse telemetry repeatedly restricts the flow of mud to generate a pressure increase measured at surface directly proportional to the flow restriction downhole to propagate pressure signals encoding data generated by downhole sensors through the mud upward to the surface.
Electromagnetic telemetry uses current injection to send encoded data generated by downhole sensors to surface as an alternative method of telemetering downhole data.
A telemetry system may be lowered on a wireline located within the drill string, but is usually formed as an integral part of a special drill collar inserted into the drill string near the drilling bit. The basic operational concept of mud pulse telemetry is to intermittently restrict the flow of mud as it passes through a downhole telemetry valve, thereby creating a pressure pulse in the mud stream that travels to the surface of the well.
In mud pulse telemetry, the information sensed by instrumentation in the vicinity of the drilling bit is encoded into a digital formatted signal and is transmitted by instructions to pulse the mud by intermittently actuating the telemetry valve, which restricts the mud flow in the drill string, thereby transmitting pulses to the well surface where the pulses are detected and transformed into electrical signals which can be decoded and processed to reveal transmitted information.
In a similar matter, electromagnetic telemetry injects a current across an electrically isolated gap in the drill collar to react an electromagnetic impulse proportional to the encoded data which is detected a surface by sensitive voltage detection methods using conductive electrode stakes inserted into the earth and/or the casing of the well being drilled to provide electrodes. This encoded data is decoded and processed in similar manner as mud pulse transmitted data.
One problem encountered in all measurement-while-drilling systems and logging-while-drilling systems is that the drilling process involves axial and radial vibrations and shocks which can interfere with smooth transmission of signals generated by the sensors. Devices known as dampeners have been developed in efforts to address these problems. Dampeners and related peripheral technologies have been described in US Patent Publication Nos. U.S.20160002985, U.S.20150376959, U.S.20150259989, U.S.20120247832, U.S.20120228028, U.S.20120152518, U.S.20120247832 U.S.20110120772, U.S.20110198126 and U.S.20090023502, U.S. Pat. Nos. 9,109,410, 8,640,795, 6,808,455, 5,964,307, 5,083,623, 3,406,537 and 3,306,078 and International Patent Application No. WO2013050231, each of which is incorporated herein by reference in its entirety.
A need exists for improvements over known shock/vibration dampener devices which provide enhanced capabilities and simplified structures to provide manufacturing advantages and ease of maintenance.
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