The Laboratory Technology Study Of Water-bearing Cracks Plugging

In this thesis,aiming at a series of problems existing in domestic and foreign,such as the limited repellent ability,easily diluted and dispersed when encountering water,easily deformed when be pressed,the insufficient ability of resisting to compression,difficulties and existing problems of that plugging agent has solidified and Clogged pipes when haven't reached leakage layer have been analyzed during the plugging processes.With the common wading crack leakage in the process of oil well plugging as the research object,the difficulties encountered and problems of Water-bearing Cracks in the process of collision have been analyzed.With the oil soluble polyurethane(OPU)as the main reagent,the indoor preparation technology of the plugging agent system delay curing agent has been researched,the feasibility of preparation technology,the slow dissolution performance and delay time performance of curing agent have been evaluated;the effect of the curing agent addition amount and temperature to the delay time and solidifying effect have been investigated,the sealing performance of the plugging agent have been tested.On this basis,the further study of optimizing the plugging agent system to improve the strength of plugging layer have been done.Using the “separating water-type” preflush and plugging agent system combined plugging technology,with the homemade simple simulation device about plugging Water-bearing Cracks,which proved that the system could form the Sealing plug that has advantages of the controllable initial setting and curing time,system quickly thickening when entering the well and Fixed-point curing.According to the different performance of four kinds of curing agent,the plugging agent system could respectively satisfy the plugging water-bearing Cracks at range of the 40?~ 90? well temperature,showing good plugging performance.The results of the experiments showed that:The best dosage of the slow-dissolving type curing agent is 18%(mass fraction)of the OPU required amount,and the initial setting time of plugging agent system could reach 43 min at40?,which Conform to the requirements of the corresponding initial setting time(35 min),the breakthrough pressure gradient of the system is up to 15.82 MPa·m-1 after be placed 6h at 40?;The best dosage of the temperature controlled type curing agent A is 22% of the OPU required amount,and the initial setting time of plugging agent system could reach 56 min at 60?,which Conform to the requirements of the corresponding initial setting time(45 min),the breakthrough pressure gradient of the system is up to 13.24 MPa·m-1 after be placed 6h at 60 ?;The bestdosage of the temperature controlled type curing agent B is 20% of the OPU required amount,and the initial setting time of plugging agent system could reach 68 min at 60?,which Conform to the requirements of the corresponding initial setting time(55min),the breakthrough pressure gradient of the system is up to 11.77 MPa·m-1 after being placed 6h at 70?;The best dosage of the temperature controlled type curing agent C is 18% of the OPU required amount,and the initial setting time of plugging agent system could reach 74 min at 80?,which Conform to the requirements of the corresponding initial setting time(65min),the breakthrough pressure gradient of the system is up to 8.62 MPa·m-1 after being placed 6h at 80?.The results of plugging agent system optimization: added the right amount of QD or SN filler,the plugging capability of original plugging agent system are improved,the breakthrough pressure gradient increased about 2~2.5 MPa·m-1 showing good plugging performance.The simulation experiments are verified technology of the application performance of the“separating water-type” pre-flush combines with plugging agent system.It proved that the system could form the sealing plug that has advantages of the controllable initial setting and curing time,system quickly thickens when entering the well and Fixed-point curing.according to the different performance of four kinds of curing agent,and the plugging agent system could respectively satisfy the plugging water-bearing Cracks at range of the 40 ? ~ 90 ? well temperature,which shows good plugging performance.