Hydrocarbon Detection & Measurement

with the waterra hs oil/water interface meters

Unfortunately there are many sites where the groundwater is contaminated with hydrocarbon products. Some of these products are lighter than water (floaters) and some of them are heavier than water (sinkers). Naturally the presence of these products is not a good thing and it is of keen interest to establish their presence and if so how much product is present.

Once the presence of hydrocarbons is established, the usual course is to implement a remediation program. Of course, there is a requirement to monitor the hydrocarbon contamination on an ongoing basis to see how the remediation is progressing.

So the question is "How does one detect and discriminate between oil and water down inside a narrow diameter well?"

suggested solution

Waterra makes a sophisticated, high quality hydrocarbon and water discrimination instrument called the Waterra Oil/Water Interface Sensor (HS series). It consists of a reel mounted graduated tape attached to a stainless steel probe. The probe incorporates sophisticated ultrasonic technology which has been shown to be more sensitive in a broader range of hydrocarbon products than conventional optical systems.

When the probe encounters liquid it either triggers a light and a buzzer informing the operator that the probe is in water or a different light and a different buzzer tone are emitted informing the operator that the probe is in hydrocarbons. The depth of the probe below the top of the well can be quickly determined by reading the measurement on the graduated tape. Hydrocarbon layers as thin as 1/16 inch (1.5 mm) can be detected.

The Waterra Oil/Water Interface Sensors (HS-1 & HS-1L) are available in metric or imperial graduations in lengths up to 300 feet (100m).

procedure

The HS-1 or HS-1L is carried to the well and the stainless steel probe is removed from its holder. The probe is then lowered down the well by feeding the tape off the reel. When liquid is encountered, the ultrasonic sensor detects the liquid and a secondary test confirms whether the liquid is conductive (water) or non-conductive (hydrocarbon). Typically, one finds and then zeros in on each interface between air, hydrocarbon and water within the well as guided by the distinct lights and buzzer tones emitted from the reel as one fine tunes the position of the probe depth. The exact depth of each interface can be obtained by recording the reading on the marker tape that corresponds to the top of the casing or other suitable reference mark.