Abstract: fluid loss additive is one of the most important additives used in oil drilling. It plays an important role in maintaining the stability of drilling fluid performance, safe and efficient drilling. In this field, the most research and rapid development have been made, and gratifying progress has been made in the field of new sulfonic polymer fluid loss additives, This is related to the position of fluid loss additive in drilling fluid and the new problems faced by drilling fluid.

Filtrate reducer products can be divided into two categories: granular materials and water-soluble polymer materials. In the early stage, granular materials were used, such as bentonite, asphalt, silica fume, peanut shell, latex, etc., but now the actual application is less. At present, most of the filtrate reducer are water-soluble geopolymer, synthetic polymer and their modified products
In recent years, many new fluid loss control agents have been developed, such as polymer / inorganic nano-m
Compound fluid loss additive, 2-acrylamido-2-methylpropanesulfonic acid as base material, amphoteric ion copolymer fluid loss reducer AADM, new bentonite graft polymer drilling fluid loss reducer, etc.

1. Natural materials and their modified products
In recent years, a series of studies have been carried out to solve the problems existing in the field application, such as further modification of polyanionic cellulose, which can improve the salt resistance, calcium resistance, high temperature resistance and filtration loss reduction ability, and significantly improve the viscosity increasing effect. Zinc nano-m material ZZ was selected as the raw material of nano-m composite treatment agent, The solution mixing method and emulsion blending method and mechanical blending method were used as the blending agent to prepare the M modified material ZOD-ZZ, which improved the performance of the drilling fluid adhesive, reduced the normal temperature and atmospheric pressure loss, and also improved the plastic viscosity and dynamic cutting force.D.

2. Starch modified products are mainly etherification and grafting, which can significantly improve the temperature resistance and salt resistance of the products. In this study, zwitterionic modified starch filtrate reducer CSJ was developed with jade m starch as raw material. Its anion substitution degree is 0.5-0.8, and its cation substitution degree is 0.2-0.4, All of them have good rheological properties and fluid loss reduction properties, and can maintain the ground structure and rheological properties of the enhanced positive electric gel drilling fluid, and have good compatibility with the positive electric gel drilling fluid, its temperature resistance and fluid loss reduction effect are lower than that of DFD.The results showed that the salt resistance and temperature resistance of the modified carboxymethyl starch were up to 140 ℃. The filtration rate was about 46% with the addition of 2% of the modified carboxymethyl starch. The salt resistance and calcium resistance of the modified carboxymethyl starch were better than those of the control group, When the amount of CCMS is 57% and 75% respectively, the viscosity increasing and filtration reducing performance of mv-cmc for drilling fluid can be achieved. In order to overcome the defects of carboxymethyl starch, etherified and grafted heat crosslinked starch were synthesized, and these two products were used as filtrate reducer for drilling fluid, When the mass ratio of etherified starch and grafted starch is 1:1, the filtration loss performance is ideal, which can reach 50%. The product has no harm to the environment. Gao Suli and others prepared AM / an / am starch quaternary graft copolymer by graft copolymerization of acrylamide, acrylonitrile and acrylic acid with starch at a certain temperature and initiator, In fresh water, saturated salt water and congruent brine drilling fluid, it has excellent filtration reduction effect and good resistance to temperature < temperature > 150 ℃, salt resistance < NaCl to saturation) and calcium < 20% pollution resistance, and has strong inhibition of shale inclusion.

The results showed that the filtration rate of modified carboxymethyl starch was about 46%, salt resistance and calcium resistance were better than that of DFD. The cross-linked carboxymethyl conformal starch < CCMS was prepared by crosslinking etherification of potato starch and chloroacetic acid, When the amount of CCMS is 57% and 75% respectively, the viscosity increasing and filtration reducing performance of mv-cmc for drilling fluid can be achieved. In order to overcome the defects of carboxymethyl starch, etherified and grafted heat crosslinked starch were synthesized, and these two products were used as filtrate reducer for drilling fluid, When the mass ratio of etherified starch and grafted starch is 1:1, the filtration loss performance is ideal, which can reach 50%. The product has no harm to the environment. Gao Suli and others prepared AM / an / am starch quaternary graft copolymer by graft copolymerization of acrylamide, acrylonitrile and acrylic acid with starch at a certain temperature and initiator, Rtcrpudgit has good filtrate reduction effect in fresh water, saturated brine and congruent brine drilling fluid, and has good resistance to temperature < temperature > 150 ℃, salt resistance < NaCl to saturation) and calcium < > 20% pollution, and has strong inhibition of shale entrapment.