Low-viscosity carboxymethyl cellulose (CMC) and low-viscosity polyanionic cellulose (PAC) are commonly added to modern drilling mud compositions as fluid loss reducing agents. Currently, starch-based reagents are not widely used due to their high biodegradation (биодеградии) and low heat resistance. However, when carboxymethyl is added to starch, its bacterial and thermal resistance increases. Therefore, taking into consideration the fact that the cost of carboxymethyl starches (CMC) is 30-50% lower than and low-viscosity polyanionic cellulose (PAC), the most crucial goal of the research is to understand if it is possible to substitute PAC for CMC in some types of the drilling muds. However, in our research is it shown that in order to get some comparable properties of the various systems of the drilling muds, it is necessary to keep the content of the active and inert solid phases at a certain level. It is not possible to adequately substitute PAC for CMC when solid phase is in the low content. However, it is common knowledge that the content of the active and inert solid phase in the drilling mud composition is higher than it is minimally required in order to obtain equal properties when CMC is used instead of PAC. Also, the production-scale CMC, which degree of substitution in carboxymethyl is about 30, does not have sufficient thermo- and salt resistance. Moreover, they are subjected to the quick biodegradation in the fresh system (пресная система). That is why the samples of reagents with the degree substitution more than 60 were synthesized. The properties of CMC when it is used as fluid loss reducing agent have comparable filtration drilling mud properties to the mud compositions under study, therefore, they can be recommended to be used in the drilling muds instead of PAC.
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