Polymer polyacrylamide (PAM) is not only a high-efficiency flocculant, but also an extremely excellent thickener because of the high viscosity of the aqueous solution. PAM has the functions of thickening, flocculation and rheological adjustment, etc. Additives that can be used for multiple purposes in oil extraction, such as drilling fluids, fracturing fluids, and polymer flooding to improve oil recovery (EOR). In oil extraction, the key to the application lies in the combined use conditions and requirements , Reasonably design and select its composition structure, such as molecular shape, molecular weight, ion degree, etc., and the correct construction process.
1. PAM is used as a drilling fluid additive
Drilling fluid is used as a drilling mud performance modifier in oil production. The role of PAM is to adjust the rheology of the drilling fluid, carry cuttings, lubricate the drill bit, and facilitate drilling. In addition, it can also greatly reduce stuck drill accidents and reduce equipment wear. And can prevent the occurrence of lost circulation and collapse, and make the well diameter regular. In this regard, partially hydrolyzed polyacrylamide is often used, which is obtained by the hydrolysis of PAM or polyacrylonitrile.
2. PAM is used as polymer flooding
Among the methods to improve oil recovery, polymer flooding technology occupies an important position. The role of polymer is to adjust the rheology of injected water, increase the viscosity of the driving fluid, improve the efficiency of water flooding, and reduce the water penetration in the formation. Rate, so that water and oil can flow forward at a uniform speed.
Polymer flooding is by adding a certain amount of polymer polyacrylamide to the injected water to increase the viscosity of the injected water and improve the oil-water mobility ratio. Due to the absorption and trapping of polyacrylamide molecules by the oil layer, the height is reduced. The permeability of the medium permeability layer or the high and medium water flooded layers increases the seepage resistance of the injected water, increases the water absorption of the low permeability layer or the low and unwatered layer, and expands the scope of the injected water on the oil layer plane. And the thickness of the water flooded in the longitudinal direction of the oil layer, thereby expanding the water flooding volume, displacing the unused crude oil during water flooding, and achieving the purpose of improving oil recovery.
3. PAM is used as a water shutoff agent
In the oilfield production process, due to the heterogeneity of the formation, water flooding problems often occur, and water shutoff is necessary. The essence is to change the penetration state of water in the formation to reduce oilfield water production, maintain formation energy, and improve the ultimate The purpose of recovery factor. PAM chemical water plugging agents have a selective effect on the permeability of oil and water, with less reduction in oil permeability and more reduction in water permeability. It can be used without cross-linking or can be used. Cross-linked with aluminum salt, chromium salt, zirconium salt, etc. to form a gel, and some resins can be added to form an interpenetrating polymer network (IPN) to make it have higher temperature resistance. For example, use W/O type PAM latex Chemically crosslinked with modified amino resin can form an interpenetrating polymer network water shutoff agent, which has been used in oilfield water shutoff and has achieved obvious results. PAM can also be used to adjust the water absorption profile in the formation and block large pores. Good results have been seen in China.
4. PAM is used as fracturing fluid additive
The fracturing process is an important production stimulation measure for the development of tight layers in the oilfield. Its function is to open the channel of the rock and let the oil flow through. The fracturing fluid formed by crosslinking methylene polyacrylamide has high viscosity and low friction. It is widely used because of its good suspending ability, convenient preparation and low cost.