Halliburton provides our clients with two primary services: rental of the SPIDR® system hardware and our proprietary conversion to bottom hole pressure (BHP) conditions. While these two services are frequently used together, they can just as easily be used individually.
The SPIDR® system Hardware
The SPIDR® system was originally designed in the early 1980s and at the time was one of the only digital wellhead pressure gauges in existence. Over the years we have continuously modified the SPIDR® system as new technology became available (i.e. better pressure transducers, larger data storage capacities, and USB communication). The SPIDR® system is in a state of continuous improvement, so that we can continue to provide the highest quality wellhead pressure gauge in the Industry. The SPIDR® gauge incorporates a Quartzdyne dual-quartz transducer which is considered the best quality transducer in the oilfield today. For any use of surface pressure data for pressure transient analysis, whether via a pressure build-up, multi-rate or injection fall-off, it is of paramount importance to utilize a quartz type transducer. This is because these transducers advantages in pressure resolution, data frequency, stability in changing thermal conditions, etc.
Converting Wellhead Pressure to Bottomhole Conditions
SPIDR® was originally founded to provide operators with an alternative to using downhole pressure gauges for well testing. In its infancy SPIDR® simply used existing industry models (such as Cullender & Smith) to model surface pressures to bottomhole pressure. We realized early on that these models were lacking especially as the amount of fluid that a well produces increases. To be able to truly provide this service, SPIDR® needed to develop its own models so that our technology could be used on a wider range of wells. To come up with these new models we began offering the SPIDR® to operators free of charge during their well tests so that we could perform a direct comparison between our converted SPIDR® system data and the actual downhole pressure data. By performing these trial comparison tests over the years, SPIDR® was able to use empirical data to create what we believe to be the most accurate models for converting wellhead pressure to bottomhole conditions in the industry.
Halliburton markets its conversion algorithm technology for: Single phase gas and oil or multiphase gas producers in critical flow that have a constant mass flow (no slugging). Halliburton routinely converts SPIDR® system acquired data but increasingly we are asked by our customers to convert historical pressure data from various sources such as SCADA, Subsea Tree Gauge, other surface measurement devices. We first must perform a quality check on the non-SPIDR® system data to make sure that the data set has the required sample frequency, resolution and thermal stability required for using surface measurements for pressure transient analysis.