Acid-Oxygen Synergistic Technology for Targeted Dissolution of Hybrid Organic–Inorganic Blockages in Low-Permeability Reservoirs
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Low-permeability reservoirs are plagued by persistent hybrid organic–inorganic blockages in associated water injection wells (or pipelines), particularly under harsh environmental conditions. In northern Shaanxi, China, water injection wells exhibit chronic high-pressure under-injection (>10 MPa), a critical issue linked to unresolved scaling and organic residue accumulation. Conventional chemical treatments fail in subzero winters due to reagent freezing and inefficient dual-phase targeting. Here, we developed a staged acid-oxygen synergistic system (LTDS) integrating sulfamic acid (inorganic scale dissolution), ammonium persulfate (radical-driven polymer oxidation), and alkyl polyglycoside surfactants, augmented by an antifreeze additive (YangtzeU-TRA). Multimodal characterization─elemental analyzer (EA), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), and inductively coupled plasma optical emission spectrometer (ICP-OES)─confirmed the formation of hybrid blockages. Specifically, the blockages consist of inorganic phases dominated by calcium carbonate (CaCO 3, 40.8 wt %) and iron(III) hydroxide (Fe(OH) 3, 1.3 wt %), alongside organic components (20 wt %) that are identified as oxygen-rich polymers (characterized by the presence of carboxyl [−COOH] and amide [−CONH 2 ] functional groups via FTIR analysis). The LTDS system achieved ≥85% dissolution within 1 h and ≥90% within 12 h at 40 °C. Crucially, LTDS retained fluidity after 48 h at −20 °C (no coagulation), addressing winter operational failures. The field test results of 3 typical wells all showed a sustained pressure reduction effect: post-treatment injection pressure stabilized at 2 MPa (vs pretreatment >10 MPa), with 100% single-operation success and 6 month stability. This study provides a solution for the dual-target dissolution of complex blockages in low-permeability reservoirs, which has direct implications for energy security and sustainable hydrocarbon recovery.
Source: ACS Omega
Authors: Chunmin Qi, Yu Xia, Shanfa Tang, Lianji Zhao
Language: English
Subfield: Ocean Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,935
OpenAlex ID: W4415313726