Research The Plugging Meathed Which Is Used For Fractured Reservoirs

Reservoir plugging is different from ordinary plugging,such as: the borehole should not be blocked thoroughly,there is easy way for plugging relief,minimize pollution as much as possible.In this paper,we consider the fractured formation in Northeast Sichuan area as the target area.In the area of special engineering geological background,DTR,all levels of granularity of calcium carbonate,common plugging bridging material and fiber material are selected as basic material research.We have studied on a series of fractured reservoir temporary plugging method by improving technology and adding special material.Fractured reservoir temporary plugging method is specifically designed for fractured reservoir plugging requirements.The specific plugging procedures are as following: firstly,shut-off plug injection method,inject the first slurry into the leakage formation,carrying the bridging and fiber materials as well as completely dissolved scaling agent(JG-1).The bridge interaction between bridge and fiber materials will plug the fracture firstly.The big gap becomes smaller gradually.Then,inject the second slurry into the leakage formation,carrying A small amount of additives and a certain proportion of another scaling agent(JG-2).When the two different kinds of scaling agents meet with each other,a large number of creamy precipitate can be quickly generated.Precipitate,as deformable particles,can be adsorbed on the surface of fiber material.The sealing layer can be further filled and strengthen.In practical application,according to the situation,the amount of scale can be controlled by adjusting the proportion of the two kinds of scaling agents.Crack width can be controlled by adjusting the size of bridge and fiber materials.In the late development stage,de-plugging of blocking layer can be realized by acidizing treatments.The corrosion rate of the materials is above 40%.Based on the theory of fractured reservoir temporary plugging method,a practical experiment is designed.The quantity and ratio of materials were selected through the experiment.The experiments are as follows:(1)scaling experiment,calculate and observe the scaling effect,select the materials taking the raw material cost into account.(2)Scaling corrosion experiment and common plugging materials corrosion contrast test.(3)Compatibility experiment of materials.(4)Pressure plugging experiment,simulated plugging experiment by a standard module.(5)Plug removal experiment,estimate the plug removal effect by the recovery rate of permeability.The material proportion was optimized by the experiment,the construction method of fractured reservoir temporary plugging was finally confirmed.Fractured reservoir temporary plugging method was further improved and amended via the experiment.And ultimately the material plan was determined.The experiment results show that the overall scale effect of the scaling agent is good.Scaling product has good adsorption effect on fiber material.Nearly no sink phenomenon was observed.Adding different amount of scaling agent,the average scaling rate is 96.14%.The average corrosion rate of the scaling agent is 95.48%,the corrosion effect is good.In the pressure plugging experiment,the bearing capacity reaches up to 6 MPa.The filter cake forms fast and amount of leakage is small.Through a series of experiments,fractured reservoir temporary plugging method is reasonably designed.Plugging and block removal efficiency are excellent.Protective effect of leakage loss of fractured reservoir is good.This method will have a good application aspect.