| With the exploration and development of deep and ultra deep oil and gas reservoirs at home and abroad,the drilling fluid system and key treatment agent that can adapt to the complex downhole conditions of high temperature and pressure become one of the key technologies to ensure the drilling and completion of deep and ultra deep wells.At present,the commonly used polyacrylamide viscosifiers in China are difficult to resist the high temperature of 180 ?,especially in the brine system.Therefore,how to optimize and improve the temperature and salt resistance of polyacrylamide viscosifier was studied in this paper.In this paper,six kinds of polyacrylamide with different molecular weight are selected as the optimization basis.Firstly,the products with the highest apparent viscosity retention rate are selected under the same dosage and the same temperature conditions.Then,three compensation optimization experimental methods of deaeration,cross-linking and synergistic effect of deaeration and cross-linking are used to carry out indoor optimization research,and a new type of temperature and salt resistant polymer viscosifier SYS is obtained,including polyacrylic acid The mass fraction ratio of amine,deaerator and crosslinker is 100:25:12.5.The compatibility of the new viscosifier SYS with the low earth phase salt water polymer drilling fluid system was evaluated in the laboratory.The evaluation results showed that the apparent viscosity retention rate of the system after aging at 200 ? for 16 hours was kept at 68.6%,which effectively improved the temperature resistance of the low earth phase salt water polymer drilling fluid.The application of layer exploration and development provides a good technical support.However,the laboratory experiments also show that the new viscosifier is prone to over crosslinking instability,and it is necessary to further explore the synergistic factors of deaeration and crosslinking and the mechanism of high temperature resistance. |
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