First, polyacrylamide used in oil extraction:
(a) polyacrylamide used as an oil repellent:
In the three oil recovery methods to improve oil recovery, polyacrylamide as an oil repellent occupies an important position. The role of the polymer is to regulate the rheology of the injected water, increase the viscosity of the driving fluid, improve the efficiency of the water drive wave, reduce the permeability of the water phase in the formation, so that the water and oil flow forward at a uniform rate. When using micelles/polymers to drive oil, the surfactant and additives are first formulated into a microemulsion with ultra-low interfacial tension and injected into the injection well, then the polymer solution, and finally the water. The water is plunger flow forward to drive off the residual oil dispersed in the pore space and improve the crude oil yield. Polyacrylamide used for tertiary oil recovery generally has a mass fraction of 10%-50% and a relative molecular mass from several hundred thousand to more than ten million. China's large oilfields, including Daqing, Shengli, Liaohe, Dagang and so on, have entered the middle and late stage of exploitation, and the comprehensive water content of the extracted oil is increasing day by day. In order to stabilize the production of oilfields in the east of China, it is imperative to adopt the three times oil recovery technology to improve the oil rate and ensure the stable production of oilfields. Daqing oilfield has industrialized and popularized the application of polyacrylamide oil repellent experiments, and achieved good oil effect.
(b) polyacrylamide used as a water plugging adjuster:
In the oilfield production process, due to the non-homogeneous nature of the formation, often resulting in water flooding problems, the need for water plugging, the essence of which is to change the seepage state of water in the formation, in order to achieve the reduction of water production in the oilfield, to maintain the energy of the formation, and to increase the final recovery rate of the purpose of the oilfield. Polyacrylamide chemical water plugging agent has the selectivity to the permeability of oil and water, the permeability of oil can be reduced up to more than 10%, while the permeability of water can be reduced by more than 90%. Selective water plugging this feature is not other water plugging agent, usually depending on the type of stratum to choose the appropriate molecular weight of polyacrylamide. For oil formation with good homogeneity and high average permeability, polyacrylamide with medium relative molecular mass of 5x106-7x106 can be used; for fractured oil formation with low permeability of bedrock or oil formation with big change of permeability, polyacrylamide with high relative molecular mass of 10x107 can be used. Polyacrylamide can be used without cross-linking, and can also be used with aluminum salt, chromium salt, zirconium salt and other cross-linking to generate a gel, and can also add certain resins to form an intercompatible polymer network, so as to make it have a higher temperature resistance. The method has been applied in the domestic carbonate bottom water reservoirs of high water content oilfield plugging water, and achieved significant results. The use of polyacrylamide can also adjust the water absorption profile within the formation and seal large pore channels. Good results have been achieved in practice.
(c) polyacrylamide used as a drilling fluid adjuster:
Polyacrylamide as a drilling fluid adjuster, often using partially hydrolyzed polyacrylamide Hp, which is hydrolyzed from polyacrylamide. Its role is to regulate the rheology of the drilling fluid, carry rock chips, lubricate the drill bit, reduce fluid loss and so on. The drilling mud modulated with polyacrylamide has a low specific gravity, which can reduce the pressure on the oil and gas layer and clogging, and it is easy to find the oil and gas layer, and is conducive to drilling, and the drilling speed is 19% higher than that of the conventional mud, and 45% higher than that of the mechanical drilling speed, in addition, it can greatly reduce the jamming accidents, reduce the wear and tear of the equipment, and prevent the occurrence of well leaks and collapses
(d) Used as an additive for fracturing fluids. Fracturing process is an important production increase measure for oilfield development of tight layer. Fracturing fluid cross-linked with methylene polyacrylamide is widely used because of its high viscosity, low friction resistance, good sand suspending ability, low filtration loss, good viscosity stability, low residue, wide source of supply, and easy preparation and low cost.
Second, polyacrylamide for water treatment:
The amide group of polyacrylamide can be affinity and adsorption with many substances and form hydrogen bonds. High molecular weight polyacrylamide in the adsorbed particles to form a bridge link, generating flocs, conducive to particles sinking. Polyacrylamide type flocculant can adapt to many kinds of flocculation phenomena, its dosage is small, high efficiency, less sludge generated, easy post-treatment, and it has special value for some cases. China's raw water treatment, municipal wastewater treatment and industrial wastewater treatment industries are using polyacrylamide as flocculants to varying degrees. Polyacrylamide is currently the most widely used and most effective polymer organic synthetic flocculant.
(3) Polyacrylamide is used in paper making.
Polyacrylamide in the paper industry is mainly used in two aspects: one is to improve the filler, pigment and other retention rate to ...... >>
Question 2: What is polyacrylamide used for? Use characteristics
1) flocculation: PAM can make the suspended material through the electric neutralization, bridging adsorption, flocculation.
2) Adhesion: PAM can be mechanically, physically and chemically bonded.
3) Resistance reduction: PAM can effectively reduce the friction resistance of the fluid, adding trace PAM in water can reduce resistance by 50-80%.
4) thickening: PAM has thickening effect in neutral and acid conditions, when the PH value is above 10 PAM is easy to hydrolyze. When it is semi-network structure, thickening will be more obvious.
Introduction to the principle of PAM
1) The principle of flocculation: PAM is used for flocculation, with the flocculated species surface properties, especially the kinetic potential, viscosity, turbidity and pH value of the suspension is related to the surface of the particles of the kinetic potential, is the cause of particle blocking to join the surface of the opposite charge of the PAM, the speed of the kinetic potential is reduced and cohesion.
2) Adsorption bridging: PAM molecular chain fixed on the surface of different particles, the formation of polymer bridges between the particles, so that the particles form aggregates and settle.
3) Surface adsorption: various adsorption of polar groups particles on PAM molecules.
4) Enhancement: PAM molecular chain and the dispersed phase through a variety of mechanical, physical, chemical and other roles, the dispersed phase is implicated in the formation of a mesh, thus playing an enhanced role.
Question 3: What is the main role of polyacrylamide in concrete? The effect of polyacrylamide in concrete, pam flocculant on cement concrete bridge deck paving layer, can improve the flexural strength, bond strength, bending toughness and abrasion resistance has a significant effect, and can reduce the compression and folding ratio, permeability and shrinkage. We generally recommend anionic flocculants due to their high viscosity, low price and good water retention. We will also use it as a thickener on top of putty powder, on top of mortar king, concrete, basically to improve the viscosity of the product, the scope of application is a little more extensive. Whether it is anionic or non-ionic products are utilized to increase viscosity, water retention, flocculant, lubrication and other characteristics, to play its unique application advantages.
Studies have shown that adding small amounts of organic polymers, such as polyacrylamide, to cement concrete has become a new trend in improving the performance of cement concrete. Because of the long molecular chain structure of organic polymers and macromolecules in the bond joints or chain segments of the self-rotating nature of the decision and inorganic non-metallic materials with different properties - elasticity and plasticity, so the addition of polyacrylamide in the concrete can improve the density of concrete. Polyacrylamide is a water-soluble polymer, has good flocculation, can reduce the friction resistance between the liquid, according to the ionic properties can be divided into non-ionic, anionic, cationic and amphoteric type four types.
In the use of some people will use anionic as glue to use, usually do glue using 16-18 million molecular weight of anionic polyacrylamide can be, if the molecular weight is too low, the proportion of the amount of production out of the significantly lower, the quality can not be guaranteed. Some studies have proved that polyacrylamide on cement concrete bridge deck pavement layer, can improve the flexural strength, bond strength, bending toughness and abrasion resistance has a significant role, and can reduce the compression and folding ratio, permeability and shrinkage. According to the reaction of customers who have used the general use of anionic polyacrylamide can be applied almost.