242 results about "Sensitivity test" patented technology

The invention relates to a crack initiation and propagation and supporting crack stress sensitivity evaluation device and method. The device comprises a core part, a confining pressure loading part, afracturing fluid pumping part, a stress sensitivity test part and a crack monitoring part. The method comprises: step 1, setting X, Z, and Z triaxial pressures, and applying triaxial load to a core;step 2, calculating the uniaxial permeability or the triaxial overall permeability of the core flowing from a shaft to a reservoir or from the reservoir to the shaft; step 3, adding fracturing fluid into an intermediate container I as prepad fluid, and adding the fracturing fluid and a proppant into an intermediate container II as sand carrying fluid; step 4, injecting the prepad fluid into the core and injecting the sand-carrying fluid into the core after the core is pressed open; and step 5, injecting water or gas into the shaft or a triaxial seepage plate, and calculating the uniaxial permeability or triaxial overall permeability of the core flowing from the shaft to the reservoir or from the reservoir to the shaft after fracturing. The crack initiation and propagation and supporting crack stress sensitivity evaluation device and method can guide the optimization of hydraulic fracturing construction parameters and effectively improve the productivity of oil and gas wells.

A method and apparatus for testing a pulse oximeter which is based on the concept of an electrical interface between the testing instrument and the oximeter rather than an optical interface. The pulse oximeter signal processor is tested separately from the probe, and still further, the optical elements, that is, the LEDs and the photodiode, of the probe are tested separately from the probe cable. With the probe disconnected from the oximeter, a modulated electrical test signal representative of SpO2 values and other parameters is generated in response to an electrical signal from the oximeter, and the test signal is applied to the oximeter signal processor, whereby the display of the oximeter shows a value of SpO2 which is compared with the SpO2 value represented by the test signal. Independently, the probe including the probe cable, the LEDs and the photodiode are respectively and separately subjected to continuity and optical sensitivity tests. Each of the main components of the oximeter is thereby separately analyzed, and the source of a defect is isolated.