The plug-and-perf (PNP) completion method is an industry standard that uses a single wireline run to set a bridge plug for isolation and then perforate the next interval or stage prior to fracture stimulation. The wireline assembly, when used in horizontal applications, is pumped downhole to reach the desired depth and then pulled to the surface after perforations are made, allowing fracture operations to commence. Plug spacing has been a major industry topic, with most trends over time showing reduced spacing with more plugs per completion. This is primarily due to fracture designs continuing to evolve as well as production results altering designs to space plugs closer together for maximum contact with the reservoir.

However, there are countless costs, risks and time associated with running, setting and drilling plugs during the completion of a new well. A bridge plug can become prematurely set (preset) prior to reaching its desired depth during a wireline pump-down operation, adding unintentional time and money to the overall completion. Technological breakthroughs that can decrease the number of plugs needed in a single well but still achieve great and possibly better results have significant value to operators.

Reduce plugs

Thru Tubing Solutions’ SlicFrac diverting technology allows operators to reduce the total number of bridge plugs within a wellbore while maintaining the advantages of closer stage spacing and additional clusters. The risk of a preset is drastically reduced along with pump-down time, completion costs and resources associated with the corresponding wireline runs and subsequent millout work.

Applying the SlicFrac diversion technology between bridge plugs allows the operator to achieve maximum cluster efficiency while stimulating the entire stage without leaving orphan clusters behind. By spacing the plugs farther apart and adding additional perforation clusters, operators are able to perform more pinpoint fracture stimulations while diverting the treatment to the virgin formation, which ultimately would have been left untreated in the previous design. The use of a SlicFrac diverter system can increase fracture fluid efficiency across the entire stage to contact the most rock possible, giving the target reservoir every opportunity to perform to its full capacity.

Protect offset wells

Stimulating neighboring wellbores could potentially harm production of the original (parent) well and also leave the new (child) well underperforming in comparison to the original well. Maintaining near-wellbore stimulation of the child wells can help eliminate the bashing effect on the parent well and allow more wells to be drilled in the field with positive results. A SlicFrac diverter system allows the operator to maintain a more consistent stimulation volume into each perforation cluster, ultimately providing a more balanced treatment and reducing the probability of a “runaway fracture” that could damage offset wells. This can be important to operators drilling infills so as not to communicate with other wells in the field.

Case study

The SlicFrac diverter system was used on an infill drilling project where the customer was concerned the parent well could potentially suffer from communication while stimulating the new well. Pressure gauges deployed downhole into the parent well by the customer measured an increase of 82 psi throughout the entire job (Figure 1).

FIGURE 1. As indicated by the chart, the parent well had an 82-psi increase during the SlicFrac operation of the child well. (Source: Thru Tubing Solutions)

The customer was able to optimize placement of the proppant and divert the treatment when necessary to breakdown virgin clusters, removing the possibility of dominant clusters taking more than the designed fl uid and fracturing into the offset wells. In addition, the customer was able to reduce the total number of bridge plugs used, and this led to a more efficient fracture job with less risk at a reduced cost.

SlicFrac Perf PODs seal directly inside the perforation and eliminate any formation damage or residual fracture obstructions, making them ideal for both new and existing/washed perforations. The Perf POD replaces the need for numerous bridge plugs while providing an economical solution for better fracture stimulation by selectively diverting the fracture to the virgin formation.

The customer’s production numbers for the first 60 days of the child well showed equivalent values to that of the parent’s first 60 days when completed a year prior; thus eliminating any concerns in regard to depleted resources (Figures 2 and 3). SlicFrac Perf PODs were able to eliminate interwell communication within these neighboring wellbores while also achieving higher than expected production numbers in the new well. Additionally, the new well produced 49% less water than the parent that had been originally completed using a conventional PNP operation.

The customer considered the results to be a huge success and has since decided to include the SlicFrac diverter system in all future fracture stimulations to achieve maximum cluster efficiency and remove runaway fractures. The overall reduction in plug cost, wireline runs, water usage, total fracture time, post-fracture millouts and all-inclusive time for services on location all attribute to the total cost savings with the diverter system.

FIGURE 2. This chart shows the production comparison for the parent well and the new well for the first 60 days. (Source: Thru Tubing Solutions)

FIGURE 3. Oil and gas production from the parent well increased after the fracturing of the child well. (Source: Thru Tubing Solutions)

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