Yang Boli, Xu Hongxing, Wang Yue, Du Juan
Changqing Downhole Technology Company, CNPC Chuanqing Drilling Engineering Co., Ltd., Xi'an 710018, China.
National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China.
ACS Omega. 2025 Aug 18;10(34):38844-38851. doi: 10.1021/acsomega.5c03431. eCollection 2025 Sep 2.
Conventional acidizing struggles to remove complex, organic-rich scales in oil wells, and while strong organic solvents can help, their high cost and safety risks limit field use. To overcome these shortcomings, we developed a low-cost, safe permeability-enhanced-dispersion (PD) technique that first loosens and disperses the scale and then applies acid for thorough cleanup. The PD fluid (DL) contains a mutually soluble fatty alcohol amide phosphate dispersant (DL-F), ethanol, a surfactant blend, and a self-generating acid. Shale-oil scale from the Chang 7 Member was compressed into cylindrical cores to mimic mixed (inorganic + organic) deposits, and a new two-step protocolPD pretreatment followed by acid floodingwas evaluated through pressure decline, weight-loss measurements, and 3-D surface morphology. Relative to direct acidizing, PD pretreatment increased acid dissolution power by ≈ 20%, doubled overall dissolution efficiency in core-flood tests, and generated multibranched etched channels that markedly improved cleanup uniformity. A field pilot on Well H1 (September 2024) confirmed laboratory findings: daily liquid production rose from 6.13 (47.7% water cut) to 11.95 m d (42.3% water cut) 6 months after treatment, adding ∼350 t of oil. These results demonstrate that the PD-acid sequence provides a fast, deep, and even damage-removal alternative to costly organic solvents, offering a safe, economical method for routine acidizing of homogeneous reservoirs and showing strong potential for wider field adoption.