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The Midland Basin Wolfcamp/ Cline Shale Horizontal Oil Play


The Midland Basin Wolfcamp/ Cline Shale Horizontal Oil play is one of the hottest in the U.S right now.

Lately, industry buzz has touted the potential of the Wolfcamp/Cline to be bigger than the Eagle Ford and Bakken combined.

However, it is still in an early phase of development compared to these other more mature plays, and figuring out how much of the potential is recoverable may decide the ultimate winner. Plus, you can’t forget about the economics, and taking that into account, the Eagle Ford’s shallow wells, available services, operator efficiency and high productivity wins every time.

Whether you choose to believe the hype or not, there’s no hiding that the entire Wolfcamp/Cline interval is thick and prolific. The potential for stacked lateral development has attracted some large and very efficient operators. Let’s explore these various producing intervals and compare which is the best performer.

Determining a Well’s Interval

To define the well’s producing interval, I first subset the Wolfcamp/Cline play area down to the core counties of Glasscock, Sterling, Reagan, Irion and Crockett and defined my query to only show horizontal wells.

Then, I referenced some of the main operators’ investor relations reports to investigate their key wells and what they consider Wolfcamp A, B, C, D, and Cline. For generalization purposes, I switched this to indicate Wolfcamp Upper, Middle, Lower and Cline.

Any other wells, in which their respectful zones of penetration were not specified in industry publications, I used the well’s upper perforation from the completions database to find the well’s producing interval.

I then referenced multiple type logs by county to assign the above mentioned intervals by depth.

The variation in depth of the top of the Wolfcamp was quite interesting as it dipped throughout the basin, varying hundreds of feet even within a few miles. I should also mention that I omitted all wells that had null values for its producing interval. This left me with a count of 502 wells for this dataset.

Spatial Distribution

Below is a map showing the spatial distribution of Wolfcamp/Cline horizontals in this particular area of interest. I colored by the producing interval and sized by the peak month rate of production in Boed (20:1).


Generally, there is a strong correlation between the peak month of production, which is usually the second month, and estimated ultimate recovery (EUR). The bar chart below shows the best well’s EUR value for each of the producing intervals. Once again, there are only horizontal wells in the dataset.


These types of EUR values resemble the types of EURs one might see from investor relations reports and documents. What if we looked at average instead of just the best wells?


This is what one would assume to see once the entire dataset is observed. However, these plays are still somewhat emerging, especially the Cline. Perhaps if we look at peak rate over time, there might be a learning curve involved with well optimization.


Over the past three years one can see the peak rate trending upward, even with more slightly less productive intervals drilled. The darker the bar, the more wells are represented in that year and quarter by first production date. This is an interesting data point that what one might expect to see as a play progresses in development and best practices learned.

Midland Basin Wolfcamp/Cline Shale Play In Summary

What have we learned by comparing the productivity of the Wolfcamp intervals and the Cline Shale? Long story short, the opportunity to have multiple producing intervals with solid production rates and nice rates of returns make this play very attractive.

Your Turn

What do you think? Will the Cline Shale live up to the hype? Leave a comment below.

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Matt Menchaca

Matthew Menchaca is a Research Analyst at Drillinginfo. He is a key member of the Data Management Department and the DI Analytics group. He performs industry research, tracks play development and provides various types of analysis on unconventional resource plays in the U.S. Matthew graduated from the University of Texas at Austin in 2010 after studying Geography and Geological Sciences.