Pipelining of Heavy Crude Oil as Oil-in-Water Emulsions

Abstract

This paper presents an exDerimental study on pioelining of Shanjiasi heavy crude oil as oil-in-water emulsions. Viscosity reductions of more than three orders of magnitude were achieved in laboratory by emulsification. Field trials were then made in three 4-in. gathering lines 101, 160 and 241 meters long respectively. A chemical solution was injected into the gathering line at the wellhead. Drag reductions of 40-80% were achieved provided that the formed emulsions had an injected water fraction of 0.2-0.4 and the chemical concentration was at 0.35-0.5% (based on injected water). It was also found that drag reduction was more significant at a low temperature and for a highly viscous heavy oil. A big difference existed between rheologi" cal data obtained from the field trials and those from laboratory experiments, and possible reasons were discussed.

Crude Oil Emulsion Properties and Their Application to Heavy Oil Transportation

“…As shown in Figure 12, viscosity reduction can be very important, more than 2 orders of magnitude [39,40]. For obvious economical reasons oil operators seek to transport as much oil as possible and as little water as possible.…”

“…To keep the viscosity of aqueous heavy oil emulsion below the required value of specification of pipelines transport (typically around 400 cP at ambient temperature), a maximum of 70 to 75% in volume of dispersed bitumen phase is acceptable. Above 70%, the viscosity becomes too high [39][40][41][42]. Viscosity of oil/water emulsions at different shear rates.…”

“…Moreover, emulsion viscosity is far less sensitive to temperature than that of heavy oil [39,40]. Simon et al [49] have also shown that restarting a pipeline after an emergency shutdown and reemulsification of oil does not pose major problems.…”

Experimental Study of Enhancing Oil Recovery with Weak Base Alkaline/Surfactant/Polymer

“…Sheng [14] also considered emulsification is the most important mechanism for EOR. Once the residual oil contacts with the alkali in different conditions, different types of emulsions will be formed [15]; for example, the O/W type emulsion has lower viscosity which makes it easier to flow through the rock throat, hence improving the displacement efficiency; the W/O type emulsion has higher viscosity which makes it easier to block the water channel, making part of the displacement fluid circumvent to unswept area, hence expanding the sweep volume. In other words, the formation of emulsion is conductive to the recovery of residual oil [16].…”

Bio-Diesel Based Additive for Enhancing Flow of Emulsion in Pipeline

“…Traditionally, heating has been used for reducing the viscosity, but it has the disadvantage of significant equipment cost and fuel consumption as well as difficulty in restarting after shutdown [10].…”