BroadBand Shield Service Prevents Frac Hits, Eliminating Sand Cleanout and Oil Deferral Concerns | SLB
Case Study
Location
Williston Basin, United States, North America, Onshore
Details

Challenge: Perform multistage stimulation treatments in two infill wells without sanding up or significantly reducing oil production in the older primary well between them

Solution:

  • Design stimulation treatments using BroadBand Shield fracture-geometry control service to minimize the risk of frac hits
  • Monitor pressure communication between wells using WellWatcher Stim stimulation monitoring service

Result:

  • Eliminated pressure communication between the infill well and the older primary well in stages using the BroadBand Shield service, compared with pressure communication observed in up to 61% of stages fractured conventionally
  • Maintained productivity of older primary well and avoided sanding up, saving an estimated USD 400,000 and more than two weeks of deferred production if a cleanout had been required
Background
Read the Technical Paper
Products Used

BroadBand Shield Service Prevents Frac Hits, Eliminating Sand Cleanout and Oil Deferral Concerns

In two infill wells, WellWatcher Stim service sees frac hits in up to 61% of stages stimulated with conventional fracturing, North Dakota

Stimulate infill wells without harming an older primary oil producer

Infill drilling accounts for more than 60% of the new wells drilled in North America, where operators have learned through experience that stimulating infill wells sometimes causes fluid and/or proppant communication into older wells due to pressure depletion also known as frac hits. This communication can be beneficial or detrimental to production. In the most severe cases, the older wells can be sanded up, requiring expensive and time-consuming cleanout operations to restore production.

For an operator in North Dakota, detrimental frac hits occurred in about half of the operator’s new completions. To avoid the problem, operator engineers tried pumping fluid into older wells while stimulating the infill wells. The technique reduced the risk of sand flow and cleanouts in the older wells but cost up to USD 300,000 per well.

The operator wanted a more efficient solution for multistage stimulation of two infill wells near a well that had been producing hydrocarbons for 7 years. The older well had a damaged liner and a fish behind the liner, so any frac hit requiring a sand cleanout would be extremely costly in terms of deferred production and intervention expenses to restore production.

Limit fracture growth and monitor pressure response

Schlumberger recommended the BroadBand Shield service for two infill wells on either side of the older primary well. BroadBand Shield delivers far-field diversion pills to limit frac hits or fracture propagation into existing producing wells.

Rather than commit to using it for both wells, the operator engineers agreed to test the efficacy of the service in several stages of one infill well, Well 2. In Well 3, all of the stages would be stimulated with conventional fracturing designs optimized for the area. In Well 2, five stages were stimulated with BroadBand Shield service and the next five stages without BroadBand Shield service, just conventional fracturing designs. This sequence was repeated until the last stage.

To analyze fluid and proppant communication between both wells, the WellWatcher Stim service was used to monitor pressure response at high frequency in both infill wells and the older well during all stages, enabling a combined analysis to clearly confirm pressure communication or lack of communication.

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Damage in the parent well precluded easy sand cleanout, so the operator was eager to avoid any detrimental frac hits while stimulating production from the two new infill wells.

Protect the older well while stimulating the new ones

The fracturing operations were completed in both infill wells as designed. For Well 3, which was stimulated with conventional fracturing designs, the WellWatcher Stim service recorded evidence of pressure communication with the older well in 61% of the stages. For Well 2, the service recorded evidence of pressure communication in 42% of the conventionally fractured stages and none of the stages stimulated using the BroadBand Shield service.

Despite the evidence of pressure communication, no sand cleanout was required in Well 1, and the operator was able to resume its production at the same rate experienced before the infill well stimulation treatments.

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In both infill wells, WellWatcher Stim service indicated many of the conventionally fractured stages experienced frac hits with the parent well. In the stages of Well 2 stimulated with BroadBand Shield services, WellWatcher Stim services indicated no frac hits.
Products Used

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