The effect of bitumen concentration and mean drop diameter and distribution on the rheological behavior
of bitumen in water emulsions was investigated. Results obtained showed that the emulsion viscosity is
severely affected by the type of drop size distribution. In fact, emulsions with a bimodal drop diameter
distribution exhibit viscosity values which were at least 1 order of magnitude lower than the viscosity of
similar emulsions, having the same bitumen concentration and an equivalent mean drop diameter, but
with a unimodal distribution. It was also found that concentrated bimodal emulsions behave like Newtonian
fluids, while the unimodal counterparts are non-Newtonian and show some pseudoplasticity. Because of
their very simple rheological behavior, bitumen in water bimodal emulsions are of great importance in
the processes of transporting, handling, and commercializing extremely viscous hydrocarbons.
In the 1990s, a new water management tool, downhole separation technology, was developed. It separates oil and gas from produced water inside the wellbore and injects the produced water into the disposal zone. Based on the different fluid the separators handle, they are categorised as downhole oil-water separators (DOWS) and downhole gas-water separators (DGWS). Two types of separators have been used: hydrocyclone and gravity separators. The authors reviewed the previous 59 DOWS installations and 62 DGWS installations worldwide, and discovered that only about 60% achieved success. Some major issues—including high costs, low reliability and low longevity—have slowed down its industrial adoption. Based on the field experiences, a good candidate well must have a high-quality disposal zone with sustainable permeability. To improve the performance of downhole separation tools, it is crucial to better understand the behaviour of the separator under downhole conditions and the behaviour of the injection zone under the invasion of various impurities in the produced water.
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AbstractThis paper presents evaluations of stability and rheological behavior of aqueous foam formulations. The stability of these systems was evaluated by the Ross-Miles method, using halflife measurements, and was studied as a function of the type and concentration of surfactants, polymers and salts. The effect of contaminants such as crude oil is also examined. A capillary tube viscometer was used to perform the rheological studies. The effect of variables such as quality of the foam, pressure system, tube diameter and polymer type is shown. Results were corrected for wall slip effect and normalized by using equalized volume corrections. Results indicated that the sensitivity of the foam to contamination with oil and salts depends on the chemistry of the foaming agent system and crude oil used. The rheological evaluations showed that the flow behavior is highly dependent on the foam quality for a given pressure, the chemistry of polymer and the tube diameter.
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