1. Field of the Invention
The invention relates generally to the design and construction of electrical connections for use in sondes and similar wellbore logging tools. In particular aspects, the invention provides devices and methods for improved packaging of electrically conductive elements within such a tool and for protecting said elements against wellbore fluids.
2. Description of the Related Art
A number of tools are known today for logging or sensing conditions within a wellbore during various portions of the well productions process. These sensing tools, or sondes, include an outer casing or sub that is often disposed into a wellbore on wireline. Alternatively, the sub may be disposed into the wellbore on coiled tubing or as part of the drill string or even production tubing. The sensing tools are capable of detecting a wide variety of downhole conditions, including temperature, pressure, porosity, resistivity, and so forth. The sensing tool generally features a sensor disposed on the outer side surface of the sub or embedded therewithin the side surface. Electronic equipment is disposed within the interior of the sub, and is typically contained within compartments behind sealed bulkheads that are located proximate each axial end of the sub. This electronic equipment typically includes processing circuitry, storage media, and power sources.
Fluid sealing is provided around the sensor to prevent entry of fluid into the interior of the sub. If damaged, however, the seal may permit fluid to flow into the interior of the sub. A typical external environment for a sonde would be one where the wellbore fluid is at a pressure state that higher than the interior of the sub. The pressure difference may range from 50 psi to 30,000 psi. Once inside the sub, the fluid may corrode or otherwise destroy the conductivity of the wiring that extends between the sensor and the components housed within the two axially-located chambers. Additionally, if either of the bulkheads are breached, the intruding fluid might easily destroy the electronic components housed within. Additionally, present techniques for constructing sondes with bulkheads and the necessary bulkhead electrical connectors are time consuming and costly.
The present invention addresses the problems of the prior art.
The invention provides devices and methods for construction of a sonde or other sensing tool that includes a side-entry leak protector connector arrangement. The side-entry leak protector connector provides for improved fluid sealing against fluid that might enter a sonde sub proximate the side-mounted sensor component. An exemplary side entry leak protector connector assembly is described having a metal body that is secured within a passage within the sub. The side entry leak protector connector assembly includes glass-sealed conductive elements and pin connectors to operably engage mating electrical connections leading to the sensor element, or elements, and to the components housed within the sub. The outer radial body of the protector connector assembly provides an annular fluid chamber to permit fluid that might enter the sub to reside therewithin. The outer radial body of the protector connector assembly also includes O-ring seals that provide fluid sealing between the protector connector assembly and the interior walls of the sub. The protector connector assembly eliminates the need for interior bulkheads within the sub.
In alternative embodiments, the side entry leak protector connector assembly includes an axial passage for cables and other components to be fed through.
Electronic equipment 34 is contained in each of the chambers 20, 22. The electronic equipment 34 may include processing circuitry, power sources, storage media or the like. Additionally, a sensor 36 for detecting a downhole condition is mounted on the exterior of the housing 18 and provides an electrical pin connector 38 that is disposed within the lateral opening 32.
A side entry leak protector connector assembly is shown generally at 40 in
The protector connector assembly 40 resides within the axial passage 28 so that one axial end 44 of the protector connector assembly 40 abuts the shoulder 30 of the passage 28. A snap ring 58 retains the protector connector assembly 40 within the passage 28.
In operation, the side entry leak protector connector assembly 40 provides superior prevention of and protection against fluid that might enter the housing 18 via the lateral opening 32. The circumferential channel 48 contains any fluid that might enter the lateral opening 32. In addition, the O-ring seals 50 provide a secondary seal against fluid ingress past the protector 40 and into the chambers 20, 22. This eliminates or reduces the need for bulkheads to be constructed within the housing 18 to seal off the chambers 20, 22 from the axial passage 28. Additionally, the glass-sealing of the conductive elements 52a, 52b within the body 42 prevents damage to the conductive elements 52a, 52b from borehole fluids.
In practice, the arrangements of the present invention provide for superior leak protection as well as ease of establishing electrical connectivity between sensors and electrical components 34 that are housed within the sonde housing or in neighboring housings.
Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.