A modified Ester-branched thickener for rheology and wettability during CO_2 fracturing for improved fracturing property

摘要

The thickening performance of CO_2 fracturing fluid was poor because of the low apparent viscosity. In Ms paper, the thickening performance of a modified silicone on liquid CO_2 is measured, and a rheology was investigated according to the consistency conefficient K and rheological index n. Meanwhile, a reservoir model was established to evaluate the fracturing property. Resultsshowed that the modified silicone contributes to improve the apparent viscosity of liquid CO_2 and decrease the rheology of liquid CO2 With the thickener content or pressure increase, the apparent viscosity of liquid CO_2 increases, and the rheological index ndecreased obviously. A reduced apparent viscosity is shown as the flow rate or temperature rises, but the rheology increased gradualually. The fracturing simulation herein shows that thickened CO_2 fracturing fluid could improve obviously the fracture properry. This modified thickener possesses the potential as a thickener and could be a reliable alternative to the thickener in CO_2 fracturing technology, and the large contact angle improved the backfiow property of this CO_2 thickener from rock surfaces. The development of CO_2 fracturing technology provides basic data for the improvement of greenhouse effect and clean mining of energy.