Exploring the Ten Habits - Habit One: Ensuring Interpretations Are Reasonable and Valid

by Bob Shoup

Bob Shoup's blog entry from earlier this year, "The Ten Habits of Highly Successful Oil Finders" sparked a lot of interest and discussion. As promised, we are now delving further into each habit, and want to invite your participation.  Read on to find out more...

Habit #1: Successful oil finders ensure that their interpretations are geologically and geometrically valid in three dimensions. Here is an investigation as to why.

At SCA, we see many prospect maps that are geologically unreasonable and often geometrically impossible. These unreasonable and impossible maps have cost our industry billions of dollars in unnecessary dry holes. These dry holes are all the more tragic when you consider the fact that all of the wells drilled on the basis of these unreasonable maps could have been avoided with the use of proper techniques. 

Figure 1

For example, one of the most common mistakes we see is the result of interpreters connecting two or more faults as one.  (Figure 1)

Figure 2

Often the two faults that are connected have throws in different directions, which we call 'screw faults'. With the exception of strike-slip faults, screw faults are a geometrically impossible interpretation. Yet we see them on many maps. They are so common that a screw fault interpretation can be seen in the user manual of one of our industry's leading 3D interpretation packages.

Any prospect that relies on a closure against a screw fault is a dry hole waiting to happen. One way to mitigate this risk is through utilization of Quick Look Techniques as developed and taught by SCA's leadership and training faculty, and also available as a printed textbook.  A classic Quick Look Technique to avoid drilling wells on prospects that rely on screw faults is to plot the vertical separation along the trapping fault (Figure 2). 

Figure 3

This technique takes less than an hour and can result in you saving your company the cost of a dry hole  (Figure 3). Overall, a pretty good investment of time.

So, now we would like to hear from you. Do you know of any dry holes that were drilled on geometrically impossible interpretations? We encourage you to share your examples (redacted as necessary to prevent release of proprietary information), so that others may benefit from your experience. If the example you send is selected for inclusion in an upcoming SCA Quick Look Techniques class, you can attend that class (or any other scheduled QLT class) at no charge.