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Collaborating Authors
Results
ABSTRACT Some coreflood literature points to the initial wettability state undergoing change during waterflooding, usually towards water-wetness. The current study aimed to directly probe the adsorbed/deposited oil components on model silicate substrates prior to and after flooding. Bare glass and kaolinite-coated glass in the initial brine were drained with crude oil and aged, after which the oil was displaced with the flooding brine. For a matrix of initial and flood brines (comprising sodium and calcium) of varying salinity and/or pH, the oil remaining on the substrates was analyzed by high-resolution scanning electron microscopy, contact angle and spectroscopy. On glass, the oil layer contacting it in the initial (aged) state retracts and detaches during flooding, to typically leave individual oil nanodroplets separated by clean substrate. Brines less able to overcome the oil-glass adhesion displayed a higher coverage of more irregularly shaped, semiretracted drop-lets and a higher frequency of larger microscopic residues. On kaolinite-coated glass, the added porosity and roughness increased the presence of these adhering, stranded residues. On bare glass, the residual deposit after high salinity flooding is generally least at intermediate flood pH 6, while residues decrease with decreasing pH of low salinity floods. However, on kaolinite-coated substrates, residual deposit is greatest after flooding at intermediate pH 6, and also increases on reduction of flood salinity
- North America > United States (0.28)
- Oceania > Australia (0.28)
Abstract Scale deposition in producing wellbores is a serious problem in the industry. The problem gets worse, when the scale is caused due to barium and strontium salts. These salts are difficult to clean as they are not easily soluble in any kinds of solution or chelating agents. In case of offshore operation, the scaling phenomenon is inevitable, as sea water injection is done. Formation of scales changes the surface roughness of the production tubing, thereby increasing the frictional pressure drop leading to a decreased production rate. Further deposition clogs the production tubing, creating hindrances for lowering tools into lower sections of the production string. In worst cases tubing replacement needs to be done, which is a capital intensive activity. Creating a super hydrophobic surface with multi-scale nano structures on the inside of the production tubing can greatly reduce the chances of scale deposition. This surface is created on epoxy paint surfaces using a feasible dip coating process. Microstructures are created on this surface using sandblast. Then nano structures are introduced on to the micro surface by anchoring 50–100 micro-meter SiO2 particles and finally completed by dip coating with nano SiO2/epoxy adhesive solution. The hydrophobicity is further enhanced by another dip coating of a low surface energy polymer, aminopropyl. The super hydrophobic surface shows a contact angle of 167.8 degrees (Cui, Yin, Wang et al. 2009) for water, and has high stability in basic and common organic solvents. The ions are carried in the water present in the crude. By increasing the contact angle for water, the chances of deposition of the ions that pose scaling can be reduced. This method may provide a long term solution for scale deposition especially in offshore fields where scaling incurs huge losses.
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.91)
- Well Completion > Completion Installation and Operations (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)