Unconventional Resources

Flowback (or cleanup) of fracturing treatments can have a profound influence on well productivity in unconventional reservoirs. The process of cleanup crosses many discipline boundaries. Given this complexity, it can be unclear who is ultimately accountable. Ensuring that someone is ultimately accountable is vital to maximizing the well results.

The most ideal form of flowback is one that maximizes production while meeting or exceeding environmental requirements.

The ideal flowback is reservoir dependent. In some reservoirs, immediate cleanup is preferential. This approach takes advantage of pressure gradients created during pumping to maximize fluid recovery (e.g., the “slowback” approach). In other reservoirs, extended shut-ins after fracture treatment can support improved productivity. In these cases, positive injection-fluid/rock interactions are encouraged and the pumped fluid may act as a form of propping agent. The challenge is in understanding what the best approach is for your environment.

Many disciplines have an effect on fracture-treatment cleanup. Reservoir and production engineers must understand the efficacy of the process by analyzing existing information such as well pressures, rates, and return-fluid composition. Completion and drilling engineers must ensure that the well trajectory and the well completion support the process of unloading fracturing fluids. Stimulation engineers must design fracturing treatments to promote cleanup. Operations engineers must manage flowback in the field to design specifications, reporting accurately and ensuring that environmental standards are met.

The ideal flowback is a virtuous cycle. The capture of fluids minimizes environmental effects. Capturing these fluids also allows them to be analyzed for fluid composition, rates, and flowback pressures, which can be used to optimize the cleanup process. The result is a cleaner environment and better-producing wells.

Achieving the perfect flowback requires multiple disciplines working in close cooperation. However, it is critical to use the talents of an individual who is capable of overseeing all facets of the process and who is ultimately accountable. Who is ultimately accountable for the fracture-treatment flowback process in your organization?

This Month's Technical Papers

Fracture Stimulation in the First Joint-Appraisal Shale-Gas Project in China

Unconventional-Reservoir Development in Mexico

Unconventional-Asset-Development Work Flow in the Eagle Ford Shale

Recommended Additional Reading

SPE 165705 Impact of Delays and Shut-Ins on Well Productivity by James W. Crafton, Performance Sciences, et al.

SPE 166176 Production Analysis in the Barnett Shale—Field Example for Reservoir Characterization Using Public Data by H. Pratikno, ConocoPhillips, et al.

SPE 164534 Time-Dependent Fracture Interference Effects in Pad Wells by Ripudaman Manchanda, The University of Texas at Austin, et al.

Simon Chipperfield, SPE, is general manager, Victoria and Northern Territory, at Santos. During the past 17 years, he has held positions in petroleum engineering (drilling, completions, and stimulation) and reservoir engineering. Chipperfield previously worked for Shell International E&P. He was awarded the 2007 SPE Cedric K. Ferguson Medal. Chipperfield has held a number of leadership positions and has authored or coauthored more than 20 technical publications in the areas of hydraulic fracturing, reservoir engineering, completion technology, and sand control. He holds a petroleum engineering degree with honors from the University of New South Wales. Chipperfield serves on the JPT Editorial Committee and the SPE International Awards Committee and has served as a reviewer for SPE Production & Operations.

Unconventional Resources

Simon Chipperfield, SPE, General Manager, Santos

01 July 2014

Volume: 66 | Issue: 7