Abstract

The development of US unconventional wells has reached the point where most new completions risk interactions with existing parent wells. Fracture driven interactions between child and parent wells result in a wide variation of production impacts but in many cases, production can be negatively affected and cannot be solely attributed to stolen reserves from the child well. Numerous damage mechanisms are identified with the two most dominant mechanisms being capillary phase trapping and fracture conductivity damage from FR-iron gels.

Multiple surfactant-nanoparticles chemistry was studied to reduce capillary pressure across multiple unconventional basins. A new chemistry was developed that significantly reduced the required amount of citric acid to remediate FR-iron gel damage. The chemistry was integrated into a novel rigless process that utilizes a diversion process combined with a specific volumetric design methodology to improve fluid distribution along lateral and into the propped fracture network and fracture-matrix interface. Case studies across two different basins are described, yielding 2-10x increases in hydrocarbon production and paybacks in less than 4 months.

This process is being commercially scaled and is being trialed on frac hit wells in other basins. This technique allows the industry to reassess damage from frac hits and potentially recover reserves that were previously thought unrecoverable. This process is being applied to wells that are underperforming as a production enhancement technique or used to target specific damages in long horizontal wells.

Background and Challenge

The development of US unconventional plays has reached the point where more than 60% of new wells are infill drilling (Lindsay et al 2018). The industry continues to evolve on the proper spacing between the new well (child) and existing well (parent) which maximizes economic return while minimizing fracture driven interference (FDI) damage to the parent. While FDIs, or frac hits, are common in all shale plays the production effects on the parent can vary significantly. Miller et al. (2016) studied 2,516 frac hits and reported the parent well experienced a negative production event approximately 34% of the time. Gupta et al (2020) looked at 500 frac hits across three different formations and reported negative production impacts 60-67%.

This content is only available via PDF.
You can access this article if you purchase or spend a download.