What is the difference between a STAGE™ System and a “Magic Tank”?

What are the typical influent and effluent oil loadings for the STAGE™ System?

My produce water is very corrosive. Does the STAGE™ System affect corrosion?

Why does the STAGE™ System have its outlet in the center of the tank?

How much gas does the STAGE™ System consume?

Suppose I pump 3,000 bbl/day through my 500 barrel conventional tank. Isn’t my residence time then 4 hours? 3,000 bbl, 6 tanks, 24 hours = 4 hrs. If so how could the STAGE™ System beat that?

What’s the big deal about getting the oil out of my injection water anyway?
Didn’t it come out of the formation in the first place?
What’s wrong with putting a little of it back in?

How do I size my STAGE™ System to be cost effective?

What levels of solids removal can I except from my STAGE™ System?

How fast should the tank be rotated in the STAGE™ System?

What is so “Magic” about rotating flow?

Answer: When we installed the very first STAGE™ System 1989, the project engineer, after seeing the outlet water said, this is a “Magic Tank” Although, our system has been called magic tank for many years, the name has now become a generic term used by most of our competitors for their skim tanks. However, most do not incorporate all of the removal processes used with the STAGE System..

What are the typical influent and effluent oil loadings for the STAGE™ System?

Answer: The approximate loadings are: influent = 400 to 500 mg/l and the effluent = 40 to 50 mg/l with out chemicals and 30 to 40 mg/l with chemicals. Test over long periods of time have shown that the STAGE™ System will effectively reduce the oil by 90% over a wide range of inlet levels.

My produce water is very corrosive. Does the STAGE™ System affect corrosion?

Answer: Yes, The gas acts as an oxygen scavenger in produced and make-up water. In addition, the long residence time allows corrosion inhibiters to work more efficient.

Why does the STAGE™ System have its outlet in the center of the tank?

Answer:The flow in the tank is a tight spiral from the outside to the inside. Water which has moved to the center of the tank’s vortex has been in the tank the longest and is therefore the cleanest.

How much gas does the STAGE™ System consume?

Answer: Although the consumption rate does depend upon the type water and the through-put, most of the gas is recycled back into the gas blanket on the tank battery. Therefore actual consumption is very small.

Suppose I pump 3,000 bbl/day through my 500 barrel conventional tank. Isn’t my residence time then 4 hours? 3,000 bbl, 6 tanks, 24 hours = 4 hrs. If so how could the STAGE™ System beat that?

Answer: If flow within a conventional tank was “first-in-first-out”, the STAGE™ System could not improve on it. In fact, due to the “pipeline effect” the residence time in most conventional tanks is only 10-15 seconds. Obviously most of the liquid in the tank does not participate in the flow. While the STAGE™ System is not 100% efficient in generating “first-in-first-out” flow, residence time of 2-3 hours is quite common.

What’s the big deal about getting the oil out of my injection water anyway?
Didn’t it come out of the formation in the first place?
What’s wrong with putting a little of it back in?

Answer: There is considerable support for the ideal that low concentrations of clean oil in waterflood injection water will do no harm. The argument is that the permeability to water around the injection well is controlled by the natural residual oil saturation after waterflooding. Any oil added by the injection water will not add to that residual to reduce the permeability to water. However, if the entrained oil serves as a binder for the undissolved solids and forms a low permeability filter cake on the face of the injection well bore hole, then the oil must be eliminated. Also, steamflooding, ocean disposal, injection below the oil/water contact and disposal require oil removal.

How do I size my STAGE™ System to be cost effective?

Answer: The tank size should be a minimum of 10% of the daily through-put for best results. For example: a 14,000 bbl/day flow rate would require a 1,400 barrel tank. This size is based on an average of < 500 m/l influent loading.

What levels of solids removal can I except from my STAGE™ System?

Answer: Although the STAGE™ System’s primary function is not the removal of solids, it will effectively reduce the very heavy and very light particles. Those particles that approach the specific gravity of the liquid may not be affected. However, a reduction of 40 to 50 percent of the TSS is not uncommon.

How fast should the tank be rotated in the STAGE™ System?

Answer: The tank works well within a wide range of flows. It must be fast enough to overcome inertia and slow enough to avoid skimming water with the oil. We size the system to fit within this range as part of the package.

What is so “Magic” about rotating flow?

Answer:The rotating flow, in itself, does nothing. The benefit from toroidal flow is that the path that the liquid must travel to reach the outlet is longer, giving more time for gravitational separation to occur.