Predictability of Crude Oil In-Situ Combustion by the Isoconversional Kinetic Approach

Abstract

One method to access unconventional heavy-crude-oil resources as well as residual oil after conventional recovery operations is to apply in-situ combustion (ISC) enhanced oil recovery. ISC oxidizes in place a small fraction of the hydrocarbon, thereby providing heat to reduce oil viscosity and increase reservoir pressure. Both effects serve to enhance recovery. The complex nature of petroleum as a multicomponent mixture and the multistep character of combustion reactions substantially complicate analysis of crude-oil oxidation and the identification of settings where ISC could be successful. In this study, isoconversional analysis of ramped temperature-oxidation (RTO) kinetic data was applied to eight different crude-oil samples. In addition, combustion-tube runs that explore ignition and combustion-front propagation were carried out. By using experimentally determined combustion kinetics of eight crude-oil samples along with combustion-tube results, we show that isoconversional analysis of RTO data is useful to predict combustion-front propagation. Isoconversional analysis also provides new insight into the nature of the reactions occurring during ISC. Additionally, five of the 10 crude-oil/rock systems studied employed a carbonate rock. No system displayed excessive oxygen consumption resulting from carbonate decomposition at combustion temperatures. This result is encouraging as it contributes to widening of the applicability of ISC.

An experimental investigation of the in-situ combustion behavior of Karamay crude oil

“…All other pseudocomponents showed similar RTO results. These results are consistent with the crude oil used in this work as well as many in the literature (e.g., Cinar et al, 2011aCinar et al, , 2011b. 5 shows the apparent activation energy versus conversion (left) and temperature (right) as well.…”

“…Effluent gas composition is measured, similar to kinetics tests, using a compact gas analyzer. Other procedures are the same as described by Cinar (2011) and Cinar et al (2011b). Two combustion tube experiments are conducted in this work.…”

Laboratory screening tests on the effect of initial oil saturation for the dynamic control of in-situ combustion

“…High CO 2 along with low O 2 productions observed during combustion tube tests are the indication of a stable combustion frontal advance. The rule of thumb which determines the good ISC candidates is that more than 10 mol% of the total produced gases should be carbon dioxide [37].…”

Influence of rock matrix in air kinetics oxidation for heavy oils

“…• According to the analysis conducted by Cinar et al (2011), a larger superficial area favors the oxygen addition reactions in the low temperature region. This is due to the largest contact surface area between the oxygen and the crude, resulting in a reaction rate´s increase.…”