Establishing a Protocol to Characterize Sludge from Oil and Water Lines

During well drilling, production, processing, transportation, and refining of the crude oil, it is common to observe sludge formation, which can contain several kinds of compounds, such as organic compounds of the oil and inorganic compounds generated during oil and/or water production. There are many procedures to prevent organic and inorganic deposition; however, to apply suitable procedures, it is necessary to identify the cause of the sludge formation. This can be achieved through a detailed sludge characterization. This study presents a sequence of techniques to characterize different kinds of industrial sludges and proposes the causes of the formation of each of them. The techniques used involved thermogravimetric analysis, successive solvent extractions, microcalorimetry, sulfide test, X-ray fluorescence, X-ray diffraction, and scanning electron microscopy. The sequence of the analyses was presented considering the amount of sample available. Four industrial sludge samples were used, two from an oil production line and two from a water production line. The protocol established to characterize the sludge was shown to be useful to identify the cause of the deposition. The main causes detected in the samples analyzed were asphaltene deposition, inorganic deposition, and inorganic compounds formed by hydrogen sulfide and corrosion products.