The SPIDR

SPIDR is an acronym for Self Powered Intelligent Data Retriever. The SPIDR was developed for pressure transient testing of oil and gas wells without running gauges downhole. The SPIDR system includes software for programming, downloading and communicating with the unit and a program for converting the acquired wellhead pressure data to bottom hole conditions and generating necessary plots for reservoir analysis

Internal Pressure Transducer The accuracy of the SPIDR is obtained from its internal pressure transducer, a shear mode, quartz crystal resonator whose frequency changes with pressure. This transducer is extremely rugged, accurate and repeatable, making it well suited for oilfield applications. The transducer utilizes a second quartz crystal for temperature compensation ensuring the pressure data is unaffected by temperature changes in the well and its surroundings Accuracy of the surface transducer can be verified before, during, and after each test, and the transducer is not subjected to the temperatures and stresses of a trip downhole. Digital data eliminates errors in reading mechanical pressure-bomb recorders.

External Transducers In addition to its internal transducer, the SPIDR can monitor two external transducers. External transducers greatly expand the utility of the system by allowing simultaneous monitoring of other process variables such as flow rate, temperature and pressure. External transducers are powered by the SPIDR, but may be located several hundred feet distant. The SPIDR utilizes 12-bit A/D converters for external transducers. External transducers are suitable for sour service and are available in several ranges with an accuracy of +/- 0.2%

SPIDR Power Supply The SPIDR is powered by three alkaline "D" cell batteries. The batteries power the SPIDR and its external transducers for two years or 5,000,000 samples, whichever occurs first.  Acquired data is stored in non-volatile memory to avoid data loss in the event of battery failure.  The battery voltage is displayed by FLOWCOM when communicating with the SPIDR.

Intelligent Sampling The SPIDR memory has a maximum capacity of over 5,000,000 samples. A sample includes date, time, sample number, pressure from the internal transducer, and readings from the external transducers. Memory capacity is reduced if external transducers are active. To maximize utilization of memory, an "intelligent sampling" technique is employed, from which the name SPIDR (Self-Powered, Intelligent Data Retriever) is derived. Intelligent sampling employs a fixed sample rate and stores or rejects each sample based on the pressure change from the last stored sample. If the change does not exceed a user-specified "pressure window", the new sample is discarded. The maximum time between samples, however, will not exceed a user-specified interval. The fastest sample rate is one per second, and the smallest pressure window is 0.01 psi. The unit can also be programmed to store data at a fixed interval.

Communication Direct Communication between the SPIDR and a computer is with either a USB cable or 9-pin serial cable. The cable is provided at no charge with the rental upon request o the user. DRC's free SPIDR communication software, FlowCom is also included. Flowcom is compatible with all current Windows operating systems. If the computer connected to the SPIDR is also connected to the internet, then remote communication with another off-site computer is also possible. The SPIDR can also be interfaced with offshore SCADA systems, providing yet another avenue for real-time data access.

Specifications Suitable for Sour Service CSA Certified ATEX Certified

Full-scale pressure .......	15,000 psi
Resolution (int trans).....	0.01 psi
Repeatability .............	0.01% of full scale
Hysteresis ................	0.01% of full scale
Linearity .................	0.01% of full scale
Accuracy ..................	0.01% of full scale
Operating temp range ......	-15 to +180F
Thermal compensation ......	Indicated pressures unaffected by ambient temperature changes within the operating temperature range.
Maximum memory capacity ...	5,000,000 data sets with 1 channel 2,500,000 data sets with 2 channels 1,700,000 data sets with 3 channels
External Transducers ......	Excitation: 5V @ 5 mA D.C. Signal: 0.8-3.2V Available for pressure, differential pressure, temperature and turbine flowmeters
Resolution (ext trans)..... Communications.............	12-bit A/D. RS-232; USB
Power supply .............. Pressure Fitting...........	3 alkaline "D" cells; life of 5,000,000 samples or two years. 1/16 in. male Swagelock
Dimensions ................	5 3/4 in. x 5 3/4 in. x 9 in.
Weight ....................	9 lbs
Housing ................... Programmable Sample Logic..	Modified cast-aluminum Class I, Group D enclosure with chemical-resistant finish. Data storage rate controlled by programmable interval and pressure window.
Fastest sample rate .......	One per second