In the oilfield industry, wells are the basis for crude oil extraction, and drilling quality is one of the key factors for crude oil production. The majority of circulating fluids used in rotary drilling are liquids, also known as "drilling fluids". The main functions of drilling fluid in drilling engineering are: (1) cleaning the bottom of the well and carrying cuttings; (2) cooling and lubricating the drill bit and drill string; (3) forming mud cake to protect the wall; (4) control and balance Formation pressure; (5) Suspended debris and weighting agent; (6) Deposition of debris on the ground; (7) Provide relevant data of drilling formation; (8) Transfer water power to drill bit, etc. The drilling fluid system is one of the most important drilling variables, often referred to as the "blood" of drilling, and is an important part of drilling technology. Now acrylamide polymers have played an important role in fluid loss, flocculation, shale suppression, dilution, and plugging of wells.

During the drilling process, the fluid loss of the drilling fluid is large, which may easily cause the hydration and collapse of the shale and cause the instability of the borehole wall. The drilling fluid and filtrate invade the formation, causing the clay to expand, blocking the formation oil gas flow channel and damaging the production layer As the filtration loss increases, the filter cake thickens, reducing the diameter of the well, causing large torque to the rotating drill tool, causing pumping when drilling, and causing large pressure fluctuations when drilling, which is likely to cause differential pressure stuck. At the same time, the thick filter cake affects the quality of cement injection, which also brings trouble to formation evaluation. Therefore, excessive fluid loss may cause great harm to rapid, high-quality, and safe drilling, and in serious cases, the well may be scrapped. Appropriately low fluid loss is one of the important properties of drilling fluids.
Polyacrylamide fluid loss control agent: The hydrolysate of polyacrylonitrile and polyacrylamide gradually develops into copolymers and multi-element copolymers with better performance, such as sulfonated polyacrylamide, temperature and salt resistance copolymer series, amphoteric Ionic copolymer. Shandong Ruihai Mishan Chemical Co., Ltd. independently researches and produces temperature- and salt-resistant copolymer series, and is a leader in the same industry at home and abroad.
Flocculant: Polymer flocculant can make the cuttings and inferior soil in the drilling fluid in a non-dispersed flocculation state, so that it can be removed by mechanical solid control equipment, which better solves the dispersion of drilling cuttings in the dispersed drilling fluid system And problems accumulated in drilling fluids. The polyacrylamide flocculants used in drilling fluid are non-hydrolyzed polyacrylamide and hydrolyzed polyacrylamide. The former belongs to full flocculant, and the latter belongs to selective flocculant.
Shale suppression and anti-collapse agent: There are many factors that affect the stability of the shaft wall, mainly geological factors, engineering factors, physical and chemical factors. Adding certain polymers to the drilling fluid can cause the stabilization of the borehole wall. Commonly used polymer shale inhibitors include PAM, HPAM and SPAM. They are adsorbed on the surface of clay particles on the well wall, forming a crisscross macromolecular film, enhancing the speed of mud shale on the well wall.
Thinner (viscosity reducer): the viscosity of drilling fluid will increase in the following situations: (1) contamination by inorganic electrolyte (2) solid particles in drilling fluid increase (3) in polymer drilling fluid, due to polymer and The effect of clay particles, etc., forms a space grid structure, which causes the viscosity of the drilling fluid to increase and the shear force to increase. The role of the thinner is to disassemble the space grid structure formed by the drilling fluid. The really desired drilling fluid performance is not at any extreme of dispersion, coalescence, flocculation or complete deflocculation, but it is desirable to adjust the solid particles to an intermediate state of moderate dispersion and deflocculation. Acrylamide polymers with small molecular weight (2 × 10³-6 × 10³) can be used as drilling fluid diluent.
Leak plugging agent: The loss of drilling fluid needs to be plugged with a leak plugging agent. There are three main causes of leakage of drilling fluid: permeability leakage, fracture leakage and cavern leakage. Plugging for different reasons requires the use of different polyacrylamide polymers, such as plugging of fractured and cavernous formations, volume-expandable PAM gel particles can be used.