Hawk - Product Comparisons

With the Hawk, CalScan has tried to design the most flexible and easy to use data recorder for any testing condition. This does not mean that there are not other solutions that people have tried. Below is a description of typical solutions you can try and in our opinion why the Hawk is a better solution overall. We urge you to do you own fact finding and actually talk to us about actually testing the Hawk for yourself against any other solution. Only then will you truly see the Hawks major advantages of sensor flexibility, safety, ease of use, and data quality. If you have not used our system before and would like to try it for yourself, we will loan the a system to you for two weeks to evaluate. The only thing we ask is you run the Hawk on the same test as your alternative solution and if you don't go with our solution you supply us with all the data from the Hawk and the other device as well..

Hawk versus Paper Chart Recorders for Gas Measurement

Paper Chart Recorders are the standard gas flow measurement tool in the oil industry have been used for decades . Built using mechanical sensors and paper as the data recording mechanism, they have several shortcomings.

The limited accuracy and stability of helical wound mechanical pressure and bourdon tube temperature sensors give typical system field accuracies between 10 and 20 percent. This is clearly unacceptable in these times of high gas prices.

Further inaccuracies are from the paper chart itself. Each chart has to be manually interpreted and is often very difficult to read, especially so with wildly vary readings as seen in the above picture of a chart recorder. Clients also want detailed digital data to do there analysis with. A paper chart is a inherently inaccurate mechanical analog recording of pressure and temperature. Testers typically must take hand reading of the flow values every 15 to 30 minutes and enter them in a computer. This give a far greater chance of human error when all the data must be hand typed in. The Hawk is typically sampling every 30 seconds, though much faster is possible, and storing the data in its onboard flash memory which can be easily download into a computer for analysis. Further with the Hawks real-time option a operator can monitor the flow test continuously so if something goes wrong the problem can be dealt with immediately not 15 minutes later.

Hawk versus Flow Computers for Gas Measurement

Flow computers have been around since the 1980's when small embedded microprocessors allowed for the creation of small onsite gas flow calculations. Expensive at the time and usually only used for custody transfer applications the accuracies and price has dropped to the point that its practical to have one on a wellhead permanently Production testing companies often decide to use one of these to measure gas flow in testing situations. Unfortunately these units were designed for production monitoring not testing and have several short comings that make it difficult to use for testing situations.

The primary purpose of a flow computer is to calculate and record the 24 hour gas flow numbers to report to a oil companies production accounting department. Internally very few flow computers store more than 1 hour readings, even if they do it has a very limited memory. The Hawk store hundreds of thousands of readings so every bit of data can be viewed and analyzed with sample rates down to 1 second.

Once the test is complete it is not very easy to actually download the data or monitor real-time. Communication circuitry is designed for power hungry SCADA and most are designed to run through explosive proof conduit, which is not practical on a portable test system. Even if communication is made software to use the data has to use SCADA protocols such as modbus and 3rd part viewers. Not easy to use or program. Why? Simply they are designed for one time setup by factory trained skilled instrumentation technicians. Ease of use and setup is not a primary concern. Be prepared to spend a lot of time training your employees on the programming and downloading the data.

Almost all flow computers designed for Division 1, continuous hazardous gas, use explosion proof cases. The ruggedness and easy of connections can be a problem as described in the above section on portability and safety. This forces you to permanently mount the unit using explosive proof conduit. Shock from traveling down rough roads can be a problem since ease of removal is not possible. Division 2, occasional gas, flow computers like the one above cannot be mounted on a enclosed separator and have to be mounted outside with explosive proof conduit supplying the interconnects.

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