The petroleum industry relies on rugged, high-temperature connectors to control down-hole drills.
By Bob Stanton, Omnetics Connector Corp.
Electronic sensor and detector systems in the gas and oil industry have become more versatile and capable than ever before. However, their use in down-hole applications has been limited because temperatures in many new producing regions exceed 175°C. Newer, high-temperature electronic modules are being developed to help the oil industry detect and manage key data – a process known as measurement while drilling. These innovations will enhance well operations and contribute to the world’s petroleum supply.
Measurement While Drilling Requires Very Rugged Connectors
Horizontal well shafts are increasingly used for gas and shale extraction and help find rich petroleum spots within an area. Each oil well shaft has a slurry that contains four drilling bits that pump water through a pipe. The water pressure inside of the pipe controls the direction of the drill and fluidic sensor detectors measure the flow of water versus the percentage of hydrocarbons present to reveal the percentage of petroleum in the slurry. This data enables operators to strategically steer the drill bit. The fluidic sensors are housed in electronic modules, which also include transducers that measure pressure and temperature to indicate the likelihood of petroleum. The electronic modules are placed immediately behind the drilling bits. Steering electronics assist in hydro-jet direction control and allow drill operators to horizontally route away from vertical shafts when needed. This method provides multiple well site opportunities within a single vertical shaft.
During operations, extreme temperatures, high shock, and vibration are common. The electronic controls, sensors, monitoring systems, and data processors must be small and rugged to fit within the module and perform with integrity during the drilling process. Component manufacturers are meeting these requirements with higher-temperature devices such as micro-power CMOS operational amplifiers for zero-drift control or quad/octal, simultaneous sampling, and 24-bit analog-to-digital converters to process data collected down in the hole while drilling continues. These small, rugged electronic devices require signal interconnection from one unit to the other to manage and transmit the data up to the surface for control.
High-temperature Micro-D and Nano-D connectors with high-temperature wiring are desirable for oil and gas applications. These connectors are common in ruggedized military applications, and are enhanced with higher temperature materials and robust design features that retain their small size and weight to achieve a combination of good fit, function, and data processing when mounted on boards deep inside of well shaft electronics.
Down-Hole Connectors Must Meet High-Performance Testing Requirements
Down-hole connectors use specially tempered beryllium copper pins plated with high-quality nickel and gold, and are tested to guarantee that they can withstand operating temperatures of 260° for over 600 hours. Mating force is also tested, assuring connectors will hold well during high-temperature cycles as specified. Special wire-to-pin crimping assures that the contact resistance remains stable and within expected ranges, such as 24 to 26mΩ. New high-temperature epoxy materials bonded with liquid crystal polymers (LCP) are used to retain the pin and wires deep inside the connector housing. Finally, the connectors are pull-tested to measure constant adhesion to the wire jacket insulation. High-performance testing examples and data are often expected in this extreme-environment industry, and connector vendors, such as Omnetics, can provide detailed test reports.
Micro-D and Nano-D connectors designed for down-hole electronics have various mounting and connecting systems to fit in standard control boards, and custom designs are beginning to appear more often. The most common metal shell option is 6061 aluminum with nickel plating. As in other electronic systems, there is a trend toward reducing the number of cables by using hybrid connectors that offer both power and signal lines within one shell and insulator system. This reduces both the size and weight of the interconnection system. These hybrid connector formats are often configured by system designers, who can consult with a connector supplier and use online design tools to produce solid models. This allows application-specific connectors to be rapidly designed and ensures a predictable fit within the petroleum-related electronic modules they serve.