摘要

Novel hydrophobically modified polyacrylamide (HMP) copolymers based on octadecyl dimethyl allyl ammonium chloride (C(18)DMAAC) were synthesized by homogeneous polymerization. The sealing performance of the HMP as sealing agent in drilling fluid was studied. The results showed that HMP-3 containing 0.66% (molar ratio) hydrophobic monomer gave the best sealing property. Compared with the traditional sealing agent, HMP-3/clay could seal the cores of different permeabilities effectively by forming a low-permeability barrier with the help of bridge material. Permeability recovery test indicated that the recovery rate of cores treated by HMP-3 systems was over 90%. The particle size analysis showed that the grain distribution of drilling fluid system can be changed by HMP-3, and the system containing HMP-3 component covered a much wide distribution, so it can be used in a wide range of pore sizes and permeabilities without foreseeing the size of pore throat definitely. This work has provide a new idea to solve the seepage losses of microfractured formations.

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