Electrical connectors and sensors for use in high temperature, high pressure oil and gas wells

An electrical connector having no glass seals, while having a single electrical conductor embedded in a thermoplastic body, with a section of the electrical conductor also being enclosed within a insulating ceramic bushing, wherein the electrical conductor has an enlarged diameter portion sized to allow the enlarged portion to sealingly engage one end of the ceramic insulating bushing, wherein such engagement prevents the extrusion of the thermoplastic body along the electrical conductor through the interior of the insulating ceramic bushing. Alternative embodiments include electrical connectors having multiple pin electrical conductors and downhole sensors.

BACKGROUND OF THE INVENTION

The present invention relates to electrical connectors and sensors useful in many applications, but particularly intended for use in hostile environments. More specifically, the present invention relates to single and multi-pin electrical connectors and sensors for use in high-pressure, high-temperature applications which commonly occur in the oilfield, but which are also encountered in geothermal and research applications.

Oil wells are being drilled to deeper depths and encountering harsher conditions than in the past. Many of the electrical connectors in the oilfield are exposed to the environment of the open well bore, where at maximum depth, pressures rise to over 30,000 psig, temperatures exceed 500 degrees, F, and the natural or chemically-enhanced well bore environment is extremely corrosive.

There have been many attempts made in the prior art to design, manufacture and market electrical connectors for use in such hostile environments, some of which have met with more success than others. For example, U.S. Pat. No. 6,582,251 to Burke et al, describes an “all plastic” body connector, i.e., all plastic other than for the metal conductor pin and the threaded metal body, in which the metal conductor pin is embedded in a molded body formed from polyetherketone (PEK), or other polymeric materials such as ULTEM, PAEK, PEEK or PEKK. When used with a threaded metal body, the plastic body will oftentimes extrude away from the metal conductor pin, causing the conductor pin to contact the metal body, causing immediate failure. At temperatures and pressures approaching 500° F. and 30,000 psi, respectively, the extrusion can be so severe that fluids leak between the conductor and the threaded metal body and flood the very instrument the connector was intended to protect.

The all plastic connector, even when not used with a metal body, will oftentimes fail, based upon the extrusion of the plastic in the instrument gland may cause the conductor pin to move so much that the connection to the boot is lost. In extreme cases the extrusions give rise to a hydraulic failure due to deformation of the o-ring gland of the connector to the point that the seal is no longer effective.

In addition to the all plastic connector, the prior art also includes U.S. Pat. Nos. 3,793,608 and 3,898,731, each to Sandiford Ring and Russell K. Ring, which disclose electrical connectors which operate quite well in harsh environmental such as very hot, very deep, high pressure wells, in which such connectors use glass seals in combination with ceramic seals.

In addition, U.S. Pat. No. 7,364,451 to John H. Ring and Russell K. Ring discloses an electrical connector for use in very hot, high pressure wells using, in combination, glass seals, ceramic seals, a plastic body molded, for example, from aromatic polyetherketones or other thermoplastic materials and in some embodiments, includes a thermoplastic jacket made from PAEK, PEEK, PEK and PEKK, or the like.

However, even with all the success experienced by the electrical connectors using glass seals in combination with ceramic seals, it should be appreciated that glass seals are relatively expensive. There thus exists a need for electrical conductors in high pressure, high temperature wells without the use of glass seals. The electrical connectors of the present invention provides some of the high pressure, high temperature capabilities of the hybrid type of connectors, but having manufacturing costs quite similar to the all plastic versions of electrical connectors of the prior art.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF INVENTION

Referring now toFIG. 1, a prior art, all plastic electrical connector10having an electrical conductor located within the interior of an all plastic body14, with the plastic body14typically molded around the metal electrical conductor12. A rubber O-ring16is also located on the exterior surface of the plastic body14. A threaded metal body18encircles a portion of the plastic body14. All too often, the plastic body14extrudes away from the electrical conductor12, allowing the conductor12to touch the metal body18, causing immediate failure of the intended function of the connector10.

FIG. 2illustrates a second failure mode of the all plastic, prior art connector10illustrated inFIG. 1. When used with a rubber boot20, the pin12depends upon electrical contact with electric conductor22in normal operation. The boot normally excludes conductive fluids from reaching the conductor while making a reliable electrical connection. Under extremes of temperature and pressure, the plastic body deforms and extrudes through the threaded metal body18, carrying with it the conductor pin12that disconnects with contact22and causing in this case both an electrical and hydraulic failure.

Thus, the all plastic connectors illustrated inFIGS. 1 and 2are prone to failure in the field, for a plurality of reasons.

FIGS.3and4A-4F illustrate an electrical connector30according to the invention having a body34molded around the metallic electrical connector pin32. The electrical conductor pin32may be comprised of Inconel, Monel, copper, Alloy 52, beryllium copper, molybdenum, stainless steel, brass, nickel-iron bearing alloys, and other known conductive materials.

The molded plastic body34is preferably comprised of insulative thermoplastic, and even more preferably from aromatic polyetherketones (PEK, PEEK) but can also be comprised of other polymeric materials such as PAEK and PEKK, and blends of PEK, PEEK, PAEK and PEKK with other plastics, thermosets, modifiers, extenders and polymers.

The insulating bushing36is comprised of a strong insulator, preferably from ceramic, zirconia, or other known strong insulators, for example, aluminium oxide (Alumina), mullite, silicon nitride, or forsterite. Non-conductive silicon carbide can also be used as a strong insulator, but it should be appreciated that some versions of silicon carbide are conductive and should not be used as a strong insulator for this application. The insulating bushing36is comprised of an electrical insulator with high compressive strength, preferably ceramic, zirconia, or similar material that will not melt, weaken or significantly degrade at well bore temperatures. The present invention does not use a glass seal.

The threaded support washer/sleeve38can be comprised from a variety of metals, but preferably is comprised of beryllium copper, Inconel or stainless steel. The O-ring is comprised of rubber. The threads on the washer/sleeve38are typically provided for installation of the connector, but are considered to be optional.

InFIGS. 4A-4F, there is illustrated a preferred process for manufacturing and assembling the electrical connector according toFIG. 3. The insulating bushing36ofFIG. 4A, the support washer/sleeve38ofFIG. 4Band the conductor pin32ofFIG. 4Care preferably fabricated as single components, and then assembled, but could be fabricated, if desired, as a single component comprising the conductor pin32, the insulating bushing36and the washer/sleeve38, or as a single component combining any one of the three components with one of the remaining two components.

FIG. 4Dillustrates, before the molding step, the assembly of components32,36and38, with the insulating bushing36being slidably engaged over the conductor pin32until preferably contacting a shoulder on the conductor pin32. As illustrated and described hereinafter, the connectors according to the invention preferably has the shoulder on the conductor pin32, but the connector according to the invention will also function in an acceptable manner without the shoulder, as illustrated and described with respect toFIG. 10. The washer/sleeve38is slidably engaged over the exterior surface of the insulating bushing36until a shoulder of the insulating bushing36preferably engages a shoulder of the washer/sleeve38. All three components are preferably assembled together, wherein such components are fixedly connected together by well known processes involving bonding, cement, glue, epoxy or other materials, in the final assembly, having melting temperatures well in excess of 500° F. to remain secure during molding at very high temperatures and very high pressures.

FIG. 4Eillustrates the assembly illustrated inFIG. 4D, after the molding step, but prior to the machining step used to achieve the end product illustrated inFIG. 4F. With the O-ring40in place, also shown inFIG. 3and inFIG. 4E, the molded body35becomes body34as a consequence of the final machining step.

Referring now toFIG. 4G, there is illustrated a partial, enlarged view of an important, but optional, feature of the present invention. In the one or more embodiments illustrated inFIGS. 3,4A-4G,5,6,7,8,9and10, the electrical conductor pin or pins each have a plurality of enlarged diameter areas, for example, areas33inFIG. 4G. The diameter of the area33is preferably greater than the diameter of the conductor pin32mounted within the interior channel of the ceramic insulating bushing36. This difference in diameter creates a seal between the thermoplastic body34(FIG. 3) and the raised area33, on the one hand, and the ceramic insulating bushing, wherein such seal prevents the thermoplastic from extruding along the conductor pin32and through the inside diameter of the ceramic insulating bushing36, thus effectively eliminating the failure modes discussed herein with respect to all plastic electrical connectors. A second seal between the ceramic insulating bushing36and threaded sleeve38prevents the extrusion of thermoplastic along the outside diameter of the ceramic insulating bushing36at location60ofFIG. 3, thus helping to eliminate the failure modes discussed herein with respect to all plastic electrical connectors.

Referring now toFIG. 5, there is illustrated a multi-pin electrical connector100, according to the invention, having a plastic body134molded around the plurality of electrical connector pins132. The electrical conductor pins132may be comprised of Inconel, Monel, Alloy 52, beryllium copper, molybdenum, stainless steel, brass, nickel-iron bearing alloys, and other known conductive materials.

The molded plastic body134is preferably comprised of insulative thermoplastic, and even more preferably from aromatic polyetherketones (PEK, PEEK) but can also be comprised of other polymeric materials such as PAEK and PEKK, and blends of PEK, PEEK, PAEK and PEKK with other plastics, thermosets, modifiers, extenders and polymers.

The plurality of insulating bushings136are each comprised of a strong insulator, preferably from refractory materials, non-conducting silicon carbides, ceramic, zirconia or other high strength insulating materials that do not melt, weaken, or significantly degrade at well bore temperatures.

The threaded support washer/sleeve138can be comprised of a variety of metals, but preferably is comprised of beryllium copper, Inconel or stainless steel. The O-ring140is comprised of rubber. The threads on the support washer/sleeve138are provided for installation of the connector into the gland and are optional.

The manufacture and assembly process for the electrical conductor100ofFIG. 5is essentially identical to the process illustrated inFIGS. 4A-4F, and may or may not have threads on the support washer/sleeve138.

Referring now toFIG. 6, there is illustrated a multi-pin electrical connector200according to the invention, having a plurality of electrical conductor pins232connected to a sensor element242embedded in the molded thermoplastic body234. The sensor element242is typically protected from the downhole environment by a cover244, as desired, and may be fabricated from metal, rubber, plastic or other known materials as needed, depending upon the type of sensor element242being used.

The electrical connector portion234ofFIG. 6is manufactured and assembled essentially identically to the process used for the electrical connector100ofFIG. 5, other than for the use of the two connector pins232connected by the conductors233and235, respectively, to the sensor element242.

Referring now toFIG. 7, there is illustrated a multi pin electrical connector300, according to the invention, having a plurality of electrical conductor pins332connected, respectively, to a sensor element341. The sensor element341comprises a plurality of electrode rings342, two of which are rings333and335which are tied electrically to the conductor pins332, respectively. The process for manufacturing and assembling the components included in the conductors illustrated inFIGS. 3,4A-4F,5,6and7,8,9and10including the materials used to manufacture the component parts of each of such electrical conductors, are essentially identical.

Referring now toFIG. 8, there is illustrated a single pin electrical connector400, according to the invention, having a single electrical conductor pin432connected to a metallic stabbing element431. The stabbing element431may preferably comprise beryllium copper, Inconel, copper or stainless steel. The component parts436,438and440correspond essentially with the corresponding component parts34,36,38and40of the connector30inFIG. 3, both as to the materials used, the assembly and the manufacturing process. However, the electrical conductor pin432is preferably fabricated as a single part to include the stabbing element431having a larger diameter than the diameter of the pin end432. The body part435and the body part434are both molded from thermoplastic, and are separated from the stabbing element431so that electrical contact with the female receptacle (not illustrated) occurs when connector400is fully engaged in the intended apparatus.

It should be appreciated that the corresponding parts of the various embodiment illustrated inFIGS. 3,4A-4F,5,6,7,8,9and10are essentially identical as to the materials used and the manufacturing and assembly process steps, other than for the first identifying digit. For example, the part436inFIG. 8is essentially identical to part36inFIG. 3.

FIG. 9is a multi-pin connector500according to the invention which can withstand high pressure from either or both directions, i.e., from the conductor pin end532and/or from the conductor pin end632. The corresponding component parts532(conductor pin),536(insulating bushing),538(threaded washer sleeve), and560(outside diameter at first end of insulating busing536) are identical to parts632,636,638and660, respectively. The thermoplastic body534and the O-ring540are common to both ends. The treaded washer sleeves538and630can be threaded, or unthreaded, as desired.

It should be appreciated that a very important feature of the present invention, is the seal formed between the thermoplastic body34inFIG. 3, the support washer/sleeve38inFIG. 3and the insulating bushing36inFIG. 3. This seal is generally noted as the external surface560along the outside diameter of the insulating bushing536inFIG. 9, but is preferably present in all the embodiments of the invention illustrated inFIGS. 3,4F,5,6,7,8,9and10. Although being preferable, such seal is optional in all such embodiments.

FIG. 10is an alternative embodiment according to the invention as illustrated inFIG. 3, but which can be used to modifyFIGS. 3,4A-4F,4G,5,6,7,8and9if desirable.FIG. 3, for example, has a raised section on its conductor pin32having an outside diameter greater than the internal diameter of the insulating bushing36creating a seal as herein discussed. InFIG. 10, the conductor pin32may or may not have the raised section, but if present, the raised section of conductor pin32does not seal against the insulating bushing36. The embodiment ofFIG. 3is preferred over the embodiment ofFIG. 10, but the embodiment ofFIG. 10will still provide a viable connector.

Thus, there has been illustrated and described herein the preferred embodiments of high temperature, high pressure electrical conductors having the ability to withstand pressures in excess of 30,000 psiq, and temperature in excess of 500° F., all without the use of glass seals in such conductors.