A Novel Crosslinked Na-cmc Fracturing Fluid And Its Performance Evaluation

Non-Newtonian fluids are often typical and conventional fluids used to fracture shale reservoirs.Fracture fluid should have the ability to carry,suspend and transport proppants to the fracture network.In order to achieve this,fracture fluids should be able to generate a high viscosity,maintain lower shear thinning,and able to break to a very low viscosity(water like),for effective clean up.Fracture fluids should also not cause too much damage that will drastically reduce the fracture conductivity of the fracture network.The most commonly used gelling agents in fracturing shale reservoirs is the guar gum.Guar maintain a considerable amount of viscosity at a concentration of 0.35wt%and able to break to lower viscosity for effective clean up.However,residues are formed after breaking and which contributes the reduction of the fracture conductivity.This research therefore focus on using a sodium carboxyl-methyl-cellulose(Na-CMC)popularly known as cellulose gum as a gelling agents to produce fracture fluid which will have the ability to also maintain a better viscosity at same concentration as guar.This work has chosen the Na-CMC over guar because of low amount of residue formed in Na-CMC and also because of the cheaper cost/abundance of the product.From our result we found that Na-CMC will give little or no residue after been broken using Sodium Persulphate,which directly translate to high regain conductivity when compared to guar.Na-CMC will maintain a better and stable viscosity at elevated temperate when compared to guar.The interlocking shape of the crosslinked Na-CMC micelles showed that it maintained an adequate viscosity able to suspend proppants.The thread-like shaped of the broken Na-CMC under the SEM images experiment showed that the fluid was broken effectively and able to clean-up.Result also showed that proppant suspension capability of Na-CMC is as good as that of guar when slot experiment was performed using alternate slug fracturing(ASF)technique.Though,during the experiments it was observed that crosslinking chemistry of Na-CMC was a great challenge and precision has to be observed.This research therefore had shown us that Na-CMC could be used as an effective substitute of guar gum considering the disadvantages guar possess which Na-CMC was able to address.