Key performance indicators (KPIs) to measure ClearWELL™’s success include production and flow rates. As long as production is constant, then the ClearWELL™ signal is effectively treating the scale and avoiding deposition and flow restriction.
Downhole ESP variables can also be monitored and used to measure success, such as pressure differential and power consumption.
Another KPI is the scaling index in produced samples from the well before and after it undergoes treatment. Since the ClearWELLTM signal prevents scale from being deposited downhole, and assists in bringing the particles to the surface in the bulk fluid, then a higher amount of scale should be detected in the produced fluid brought to surface once the well is being treated.
ClearWELL™ delays the deposition of common oilfield mineral scales, including Calcite/CaCO3, Calcium sulfate/CaSO4, Strontium sulfate/SrSO4, Barium sulfate/BaSO4, Magnesium, Silicon dioxide/SiO2, Magnesium carbonate/MgCO3 and Sodium chloride/NaCl. ClearWELL™ does not beneficially impact the formation of ferrous sulfide/FeS, paraffin and asphaltenes.
ClearWELL™ transmits its signal from the unit via an armored cable attached to the pipework by a small electrical connection box. ClearWELL™ units require a continuous 15w power source (110 - 240 VAC or 24 VDC). If a power source is not present on site, ClearWELL™ Oilfield Solutions can provide units equipped with solar panels.
ClearWELL™ units emit a train of pulses. Each pulse consists of a decaying exponential waveform with a base frequency of 120 kHz. The well tubing and casing represent an open circuit and the ground serves as the return path to complete the circuit. Placement of ClearWELL™ units requires consideration of the return path and its compatibility with the load.
The ClearWELL™ signal is corrosion neutral. The AC (bipolar) signal neither promotes nor impedes electrochemical corrosion.
Cathodic protection systems are normally electrically isolated and a ClearWELL™ system requires high frequency filters so that the ClearWELL™ signal can freely propagate while maintaining the DC electrical isolation needed for the cathodic protection program.
Properly shielded electronic systems, such as transducers and measurement systems, should be unaffected by the ClearWELL™ signal. The low frequencies employed in the ClearWELL™ system (VLF communication frequencies) are not normally used in civilian communication equipment. We expect no interference with wireless communication links in the data collection system.
The ClearWELL™ technology is patented and it is the only oilfield scale control solution of its kind.
ClearWELL™ is being used on multiple wells all over the world and based on its success in the field it is fast becoming a number one choice for scale control by operators. During development, around 20 years ago, the technology was successfully tested across more than twenty pilot field applications to demonstrate the effectiveness of the technology against scales in a variety of brines, wells and pumping systems. Related academic studies include:
SPE-170898 Preventing scale deposition downhole using high frequency electromagnetic AC signals from surface to enhance production offshore Denmark
SPE-169415-MS An environmentally friendly method to control halite scale deposition: Proved case histories from Latin America
SPE-133526-PP Physical water treatment in the oilfield
SPE-114072 Two year results of a breakthrough physical water treating system for the control of scale in oilfield applications
For most onshore applications installation is completed in under half a day by a single technician. The system must be set up specifically for each well in order to ground and transmit the signal effectively. Once set up it is simple to operate and maintain, requiring only a low continuous electrical feed which can be provided by solar panels in remote locations. The system is very straightforward to install and use on land wells but it will also work well offshore in more challenging environments with appropriate installation.
ClearWELL™ units are available for use in hazardous areas (zones 1 and 2) with full ATEX/IECEx certification. We also offer ClearWELL™ units that are listed by CSA Group as certified/verified for use in the United States and Canada.
The ClearWELL™ system is effective at preventing scale at depths of greater than 4000m.