Hydraulic fracturing, a reservoir stimulation process that involves pumping fluid into a well to break-up sand and rock formations, has become a vital method for maintaining and improving oil and gas well production. In addition, growing energy demand and healthy commodity prices have caused the industry to re-evaluate recovering remaining hydrocarbon reserves in challenging conditions such as unconventional gas formations. Techniques include using re-entry wells, and/or marginal wells. This competitive marketplace requires more efficient perforating and fracturing methods ensuring effective fracing of the formation.

New and innovative methods for isolating, perforating and fracturing include advanced fracing fluids and new perforation methods. Now, solid expandable technology is being applied to provide additional value - especially in wells associated with multi-zone fracturing in tight gas and shale gas formations where efficient completion and production strategies determine their development.

Multi-zone isolation fracturing systems are meant to ensure effective zonal isolation in different sections of the wellbore. This improves field economics by decreasing rig time, reducing time and cost for hydraulic fracturing services, accelerating production, reducing frequency of the treatments and improving reservoir drainage.

Solid Expandable Technology Facilitates Multi-Zone Isolating & Fracturing

Stimulating a multi-zone well properly is dependent on several pieces of information such as:

• interpretation of reservoir properties data


• possible well modeling


• completion configuration


• the formation's natural fracture structure

Typical zonal isolation solutions include

• bridge plugs


• straddle packers


• chemical or mechanical diverters


• external casing packers, or


• modified production packers

combined with multi-trip conventional perforation and fracturing operations and simultaneous rig and pumping activities that add cost to the overall project.

Enventure's FracSET® MaxFrac Liner is a solid expandable liner with swellable elastomer technology that requires only a single trip to install and provides instant zonal isolation. Depending on the subsequent fracing techniques, only one more trip may be required for perforating, fracturing, and cleanout operations (as well as production kickoff, if required). After the well is drilled and the solid expandable liner installed, the rig is moved to the next pad to continue optimum asset utilization.

MaxFrac solid expandable products support any type of perforating, plug and fracturing program from conventional shaped charge perforation guns run on ecoil or eline to jet perforating systems and from sand plugs to pump down composite plugs for isolation. Without mechanical complexity or drill out of components, an expandable liner provides:

• the means to individually create and fracture unlimited zones or entry points


• a much larger inside diameter (ID) than conventional solutions to accommodate larger perforating guns and larger flow areas


• lower pressure drops and higher frac rates with less required horsepower


• flush ID for ease of intervention in support of refracturing and recompletions

An expandable solution such as MaxFrac can be made up of solely expandable casing or a combination of both expandable and conventional casing. Swellable elastomers are placed as needed along the length of the system to attain desired isolation for fracture stimulation.

Real-World Application

An operator in Canada intended to use horizontal wells with multiple hydraulic fractures to develop a new gas play in a tight carbonate reservoir; however, there was an unacceptable screenout rate during the vertical well exploration program.

A high assurance of placing all hydraulic fractures was needed during the initial development phase. To isolate multiple zones while maximizing diameter, the operator installed MaxFrac liners. The maximum diameter helped reduce fluid friction during high-rate fracturing operations.

A single 5-1/2 x 7 in., 26.0 lb/ft Max-Frac expandable liner with five sections of swellable elastomers was successfully installed and expanded. All hydraulic fractures were placed, and effective zonal isolation was observed by micro-seismic imaging.

Conclusion

Applying solid expandable technology as a completion/production solution to facilitate fracturing operations is evolving to address ever-changing technical challenges and provide operators with new and more cost-effective problem-solving alternatives. By integrating solid expandable systems with other conventional and advanced solutions for isolating, perforating, fracturing and completing operators benefit from a more efficient and reliable means to maximize production rates and final recovery of reserves.