Abstract
In this current work, an unconventional fracture fluid was analysed for its rheological properties, ability to have relatively higher regain fracture conductivity after clean-up from proppant pack and ability to suspend and transport proppants to the fracture. The fracture fluid uses sodium carboxy methyl cellulose (Na-CMC) as thickener and zirconium based compound was adopted as crosslinker. This work attempts to expand on previous work done on CMC fracture fluids and results presented are completely experimental.
The crosslinked Na-CMC gel was found to have a better viscosity compared to the conventionally used guar gels made from the hydroxyl propyl guar (HPG) thickener. It was also found that CMC was able to withstand considerable viscosity at elevated temperature of about 90 degrees Celsius. Images from the Scanning electron microscope (SEM.) showed that CMC's microscopic structure with strong connected bonding was responsible for its enhanced viscosity. The fracture conductivity in pack with broken CMC fluid was found to have higher regain percentage when tested using API RR 61 cell procedure. The high residue produced in boken HPG fluid was found to be highly responsible for lower regained fracture conductivity in the proppant pack. SEM structural image analysis of the proppant versus CMC interaction may also be a responsible factor for its enhanced conductivity when compared to HPG. The alternate slug fracturing method was adapted to the CMC fluid using a fluid mobility ratio of 150-200 and success was achieved to a reasonable extent.
The overall result implies that CMC fracture fluid could be an effective substitute for guar based fracture fluid based on the improved rheology, better regain fracture conductivity and excellent proppant suspension ability of the CMC when compared the conventional guar based fluids.
