Synthesis And Application Of Chemical Plugging Agent For Drilling In Fractured Zone

In drilling construction,especially in geological drilling,it is often faced with problems such as difficulty in drilling,coring,and wall protection in complex formations.As the scope of the drilling area expands,the cost of the required wall protection also increases.At present,most of the complex formations are plugged with chemical plugging agents.Therefore,it is necessary to develop plugging agents that take into account the dual functions of wall protection and plugging to better meet the requirements of drilling and construction in fractured zones.Polymethacrylate is widely used in production and life.Compared with other plugging agents used in drilling construction,it has the advantages of low density,high strength and impact resistance,and can better achieve wall protection and plugging.Effect.At present,polymethacrylate is mainly used in construction,transportation and industry and other industries,and it is rarely used as a wall protection and plugging agent in drilling and construction operations.In this paper,the temperature resistance,pressure resistance,and pollution resistance of polymethacrylate are optimized and evaluated,and the mechanism of action is analyzed;the field application results show that polymethacrylate has good wall protection and blocking Leaking effect.The main research contents and conclusions are as follows:1.Carried out gel forming performance evaluation test,and optimized 3 kinds of test formulas.The comprehensive performance analysis is as follows:(1)Gelling time: The gelling time of the optimal formula is all 90-150 min,which meets the suitable range of construction.And it is inversely proportional to the reaction temperature and the amount of initiator added,and directly proportional to the amount of polymerization inhibitor added;(2)Temperature resistance: the applicable temperature of system is 70?-90?;(3)Pressure performance: the optimal formula is pressure-bearing The performance is good,the minimum pressure is 27.9MPa,the compressive strength of the rubber block is inversely proportional to the temperature and the amount of initiator,and is directly proportional to the compressive strength;(4)Anti-pollution performance: resin gel contains chlorinated It is poorly used in sodium formations and formations contaminated by water-based drilling fluids.It has good application performance in formations contaminated by sodium hydroxide solution,calcium chloride solution and oil-based drilling fluids,and is extremely unsuitable for application in acidic formations..(5)Viscosity change: monomer is fluid and has no viscosity.It has a certain viscosity after polymerization and its performance is relatively stable.After curing into glue,it can adhere to the broken stratum and play the effect of protecting the wall and plugging the leakage.2.In view of the development of large fracture leakage channels in some stratums,and the need to improve the retention of plugging materials in the stratum was prepolymerized and the gelling performance evaluation was carried out:(1)Six kinds of best were selected Formula,the viscosity of the polymerization reaction within 1 hour is higher than that of the non-prepolymerized system,which effectively improves the retention in the formation;(2)Compatibility with the soilless weak gel flushing fluid system used in the 28ZK6 hole field construction Better,it provides certain feasibility for field application.3.Acrylic resin was successfully applied in drilling holes in a mining area in Shandong,which better solved the malignant leakage phenomenon that occurred when drilling into the fractured zone and increased the core harvest rate,indicating that the acrylic resin has a good wall-protection and leak-stopping effect.