Tertiary cross-linked and weighted fracturing fluid enables fracture stimulations in ultra high pressure and temperature reservoir

摘要

Advancement of exploration and drilling extended the depth of oil and gas reservoir development, while it is accompanied by great challenges of abnormally high pressure and ultra-high temperature. Weighted fracturing fluid was considered as one of the key technologies to deal with this challenge in the case of existing fracturing equipment. In this work, a super guar gum with good solubility was modified from guar gum for potassium formate (CHKO2) weighted fracturing fluid and tertiary cross-linking strategy was employed to cope with ultrahigh reservoir temperature. In addition, a novel gel breaker which was completely different from the conventional oxidized breaker was designed to achieve the complete gel breaking under strong reducing conditions caused by concentrated CHKO2. The CHKO2 weighted fracturing fluid proposed in this study performed very well in static leak-off and formation damage. The density of fracturing fluid weighted by CHKO2 here was up to 1.33 g/cm(3). The applicable temperature of the fluid can reach 180 degrees C and the fracturing fluid can be completely broken, almost with no residue left after the operation. This is a very useful and practical technology for abnormally high-pressure and ultra-high temperature reservoir stimulation.