Nonpermanent Connections

Small bump arrays are valuable for the nonpermanent connections of high-density flexible circuits. Various bump constructions on flexible circuits have been developed through different manufacturing processes that are driven by the needs of specific applications. 

Reservoir pressure is measured in selected wells using either permanent or nonpermanent bottom hole pressure gauges or wireline tools in new wells (RFT, MDT, see Section 5.3.5) to determine the profile of the pressure depletion in the reservoir. The pressures indicate the continuity of the reservoir, and the connectivity of sand layers and are used in material balance calculations and in the reservoir simulation model to confirm the volume of the fluids in the reservoir and the natural influx of water from the aquifer. The following example shows an RFT pressure plot from a development well in a field which has been producing for some time. 

The permanence of a termination is determined by connection repeatability. For example, if connections are changed regularly, a nonpermanent termination should be utilized. Due to the number of reconnections, inkjet printers and electrical test probes should have nonpermanent terminations. Conversely, if a connection is to remain relatively constant, a permanent termination method should be employed. Termination method capabilities are profiled in Table 64.4. 

There have been two kinds of approaches to reahzing high-density nonpermanent flex circuits. The first is improvement in connection densities of traditional termination technologies. Crimp tabs, pressure contacts, key contacts, and FFC connectors could be categorized in this group. 

---