Aquaprocessing (AQP) is a novel method that offers higher conversion level under asphaltenes stability limit. It is a process of steam catalytic cracking using unsupported ultradispersed catalyst. Following a 2011 published work by Fathi and Pereira on upgrading a paraffinic residuum from Arab Light Vacuum Residue (ALVR) by AQP, this work investigates a proposed lumped kinetic model for the upgrading of ALVR via AQP for the first time. The model is evaluated based on experimental results conducted in a continuous upflow open tubular pilot-plant reactor under short-space times and under conditions distant from coke formation. The proposed model is based on five cascaded lumps generated at and below the asphaltenes stability limit: 540 °C+ ALVR, VGO (455−540 °C), distillates (204−455 °C), naphtha (IBP−204 °C), and gases. The model compositions are found close to the experimental values with mean absolute percentage errors (MAPEs) of <5.5%.