August 2015 - Volume 10 Issue 7

Disposal or Injector

Double Policy

Interpolating Pressure Trends

Disposal or Injector
It's more than just a name



Do you need an injector or disposal well?

The confusion between these two is understandable: they both push fluid into a reservoir.

But, in Alberta, they have very different regulatory processes and conditions. Applying for the right one can speed up approval and save regulatory headaches later.

Usually, if you can prove that pushing fluid into a formation won’t impact hydrocarbon recovery, you can apply for a disposal well.

But if you introduce fluid into a formation that will increase hydrocarbon recovery, the AER usually wants you to apply for an injection well.

Each injection well is part of an enhanced recovery (ER) scheme. Applicants are required to estimate the amount of additional recovery that will be generated. Applicants are also required to maintain a constant voidage replacement ratio.

Each disposal well is part of a disposal scheme. Disposal schemes can have many disposal wells – we’ve seen one scheme with forty-five wells! The AER requires no voidage replacement reporting for disposal schemes.

There are several other regulatory issues that pertain to one or the other that will impact your regulatory approval time. We recently saw a company that had 10 such applications refused by the regulator. We estimate that these applications would have cost about $100,000 each to prepare and submit.

Fifty percent of what you need to know to get an approval isn’t shown in the guides. Can Proven help? We know exactly what the regulator needs to get a disposal well approved.

~Granger J. Low
MetroPetro


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Did You Know
Interpolating Pressure Trends


Many engineers speak of using cubic splines for interpolating pressure data. However, the cubic splines method does not work well for interpolation when the x values are large or when they have a large distance between them. Under these circumstances, cubic splines interpolation becomes very unstable making interpolations incorrect by many orders of magnitude.

Cubic splines are also very poor for extrapolating.


 
These algorithms are not for interpolation across large distances.

Warning: Don’t use cubic splines to extrapolate beyond the data set! The boundary conditions for both types of splines virtually guarantee that the spline will not follow the trend of the points.

For pool pressure interpolation we use an alternative solution that algorithm draws a cubic through four points.

~Granger J. Low

Event
APEGA Annual Calgary Golf Tournament
Lynx Ridge Golf Club
03 Sep 2015
apega.ca
Technical Luncheon
Liquids Rich Organic Shale Recovery Applications
Calgary, AB
09 Sep 2015
cwls.org
Breakfast Lecture
Well Planning
Calgary, AB
10 Sep 2015
spe.org