Petroleum & Petrochemical Engineering Journal
Colloidal particles in produced water used for hydraulic fracturing can block pore throats in tight reservoir rocks through three main mechanisms. The blockage of these pore throats damages the permeability of the reservoir, leading to low productivity and higher operational cost. However, the characterization of these particles in produced water used for hydraulic fracturing is understudied. This study investigates the size distribution of these particles in produced water and the resulting pore plugging mechanisms potentially operating on typical 0.1, 0.2, and 0.4-micron-wide siltstone reservoir rock pore throats caused by primary, aggregate, and agglomerate particles in such produced waters. The siltstone pore throat diameters and particle diameters from untreated and treated produced water from McClean, McKenzie, Williams, and Mountrail Counties were compared and used to calculate the jamming ratios from which the main pore throat plugging mechanisms in those rocks were inferred. The results show that bridge blockage, and single pore blocking through straining are the main pore throat blocking mechanisms contributing to formation damage in these reservoir rocks. The bridge blocking mechanism is more prevalent when untreated produced water is used as the base fluid for hydraulic fracturing, while single pore blocking through straining is more prevalent in treated water. The size of the particles also affects the pore plugging mechanisms, with smaller particles causing damage through bridging and larger particles causing damage through single pore blockage and straining. These findings have important implications for the management of produced water in the oil and gas industry, as they may provide clues to minimize formation damage.
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Claudius Epie Njie, Kegang Ling, Md Jakaria, et al.. "Investigating Pore-Throat Blockage in Tight Rocks: The Role of Colloidal Particles in Treated and Untreated Produced Water" (2023). Petroleum Engineering Student Publications. 6.