Panos Dalamarinis, Enrique Proaño, and Stephen Fusselman
DG Petroleum
More than 200,000 horizontal multifractured wells are currently active across multiple unconventional basins in continental United States. The first completion designs relied on completion practices that had been utilized in conventional reservoirs, and the early wells completed with low proppant/fluid intensity and in many cases cluster/fracture spacing greater than 100 ft. Chlorine Dioxide (ClO₂) was field trialed as a Restimulation/EOR chemistry in a well D&C in 2015 as an alternative to traditional Refrac operations.
Well R is a well D&C in 2015 in Culberson County, Texas with a lateral of 7,058 ft. At the first 4,300 ft, the well was completed with a perforation design of 6 clusters 8 ft apart, followed by 183 ft of spacing to the next group of clusters. For the remaining part of the lateral, a perforation design with clusters ~38 ft apart was used. The pumping schedule was a hybrid design of slickwater/X-link gel. A Chlorine Dioxide (ClO₂) EOR Re-stimulation treatment was engineered and pumped in 01/2025, and the well, which had been shut-in since 11/2017, was returned to production
Initial production rates IP30 of ~ 230 bopd and 1,700 Mscfd were recorded (01/2025), approximately 65% of the initial production rates when the well was first put in production in 10/2015. The well demonstrates better cumulative oil/gas production and EUR when compared to the well’s initial production after 12 months of flow back. The ClO₂ re-stimulation treatment providing better economics and NPV without posing the mechanical/engineering risk of a traditional restimulation method (bull head Refrac or liner re-frac). Realized production data and performance of Well R further validated the theory presented by Dalamarinis et al . (2023, 2025) that production degradation is not exclusively related to depletion, but mainly to skin damage mechanisms developed inside the fracture system. It also expanded the range/criteria of wells at which Chlorine Dioxide (ClO₂) EOR treatments can be applied (fracture system spacing ~ 180 ft) with similar success to the cases previously presented to the industry.
Re-stimulation with Chlorine Dioxide (ClO₂) proved to be an effective method to restore production and reservoir conductivity in a well that traditionally would be considered a Refrac or Plug and Abandoned (P&A) candidate. Without the need to invest millions of dollars and operational risk in bull head or liner refrac operations, operators can utilize Chlorine Dioxide (ClO₂) as an alternative restimulation strategy that offers better economics and efficiencies.