Pinpointing the Well Spacing Sweet Spot in the Karnes Trough



Well spacing in the Eagle Ford Basin is tighter today than ever, with some wells in the Karnes Trough being drilled less than a football field apart. How did we get here? More importantly, what are the best options available to maximize production as spacing decreases? After a decade of downspacing across Eagle Ford, historical data of wells and nearby offsets hold the key to unlocking the full potential of each child well drilled.

Let’s evaluate the past decade of well spacing and completion trends in the Karnes Trough and discuss some best practices your team can leverage in the Eagle Ford and other basins.

Downspacing Trends in the Lower Eagle Ford

Let’s examine a study area in the Lower Eagle Ford containing historical offset well data from 2011 to 2019. The drilling and completion history of one of the largest Eagle Ford producers indicates the acreage is heavily focused in the retrograde gas window of the Karnes Trough. The combined number of wells from all operators in the region creates a crowded neighborhood of parent and child wells with limited spacing options. This indicates the maturity of the area and added complexity for production going forward.

This subject’s well concentration is currently in the range of 400 to 600 feet. Other operators have tighter concentrations, ranging from 200 to 400 feet. The historical trend shows this producer downspacing from 900 (2011) to 500 feet (2015), then increasing to 700 feet (2017). The producer downspaced to its narrowest spacing of 300 feet in 2019.

Completion metrics for this producer indicate a steady increase in proppant loading over the 2011 to 2019 period. This strategy seems to have been successful for productivity until 2017, but then had an opposite effect in 2018 and 2019. The downward trend coincides with significant decreases in well spacing. As the producer downspaced, most wells were co-completed, for example, drilled within 45 days of each other.

Operational and Productivity Takeaways

In evaluating this producer, the key takeaway is the diminishing returns with downspacing over the course of a decade. This is likely due to co-completion, such as creating increasingly tighter well spacing in short time periods. Parent and earlier generation child wells performed better than later generation wells essentially because they were first on the scene.

Given the current neighborhood of parent and child wells in the Karnes Trough, what are the current completion best practices for optimal productivity? These include loads of more than 2,250 proppant per foot and spacing in the 400 to 600 and 600 to 800-foot ranges, where many of the producers’ wells fall into the P75 and P90 categories.

How to Pinpoint Your Spacing Sweet Spot

Identifying optimal drilling and completion strategies is a time and resource-intensive process for a region, not to mention, for individual wells. Engineering and geoscience staff often spend significant time finding and organizing the historical data they need to analyze to guide future drilling. Such manual and repetitive workflows are inefficient, delay critical decisions that impact planned drilling and capital expenditure, and inject human error into the well planning process.

The Enverus Well Spacing tool allows engineering and geoscience staff to rapidly perform look-back analysis to understand well spacing and completion outcomes for an entire basin or sub-basin. The Enverus solution combines rich visualization, charting, and filtering with our best-in-class Enverus Drillinginfo datasets to drive well planning workflows. Energy professionals will no longer spend hours manually preparing and analyzing historical offset data, enabling them to work smarter and spend more of their valuable time on impactful analysis.

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