Can fracturing fluid be left downhole? Consequences of extended shut-in for permeability damage and residue removal in tight gas sandstone
Year: 2026
Type: article
Abstract: Hydraulic fracturing is a technique to enhance hydrocarbon recovery from tight formations. After treatment, wells are typically opened once the fracturing fluid (FF) breaks, so injected FF can flow back and reduce damage. In gas wells, immediate flowback is not recommended because the produced gas must be flared, which creates environmental and operational drawbacks, and connecting to surface facilities to preserve the gas is difficult. An alternative is to leave FF in the reservoir longer, raising the question of additional damage if the fluid remains in contact with the formation. This exploratory laboratory study evaluates whether such fluids can remain in place for prolonged periods without immediate flowback, which may reduce gas flaring and simplify post-treatment operations. It explores long-term effects of carboxymethyl hydroxypropyl guar-based (CMHPG-based) cross-linked FF on the permeability of tight sandstone formations under high-pressure high-temperature (HPHT) conditions. Permeability measurements were conducted sequentially on each sample of Scioto sandstone with formation water, broken hydraulic fracturing fluid, and formation water again, after which the samples were aged for 1, 3, and 6 months at 145°C. One month of aging produced little additional change, whereas prolonged contact for three to six months produced additional permeability impairment of approximately 11-18 % points beyond the initial fluid-induced damage, attributed to residue generated by the degraded polymer, under the tested conditions and with one core plug per aging duration. In residue removal tests, the isolated residue was soaked in 11 wt.% HCl, agitated, and heated at 145°C for 48 h, after which it was found to be soluble. The findings support the use of low-residue, thermally stable systems for prolonged shut-in periods and indicate that a post-treatment acid flush is a potential residue-removal route, although its effect on core permeability recovery remains to be verified.
Source: Results in Engineering
Institution: King Fahd University of Petroleum and Minerals
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,940
OpenAlex ID: W7204651262