Technology: general issues biopolymer calcium carbonate carboxymethylation chemical packer chemical strengthening clean fracturing fluids compound conformance control displacement efficiency drilling fluids encapsulator enhanced foam system enhanced gel system enhanced oil recovery filtrate loss reducer filtrate reducer filtration reducer free radical copolymerization fumaric acid sludge (FAS) gel gelling acid fracturing gels heterogeneous reservoir high salinity high temperature horizontal well hydraulic fracturing low temperature mixture of carboxymethyl cellulose and carboxymethyl starch (CMCS)