Synthesis Of (AA/AM/AMPS) Copolymer Nanocomposite And The Investigation Of Its Plugging Ability And Temporary Plugging Performance

In China,the frangibility-increase of many reservoirs results in the drilling fluid easily invading inside the oil formation during the drilling process,damaging the reservoir channel structure,reducing the production efficiency,and polluting the crude oil.Therefore,it is urgent to protect the reservoir permeability during the tertiary recovery phase.The common maintaining method adopted is shielding temporary plugging technology,whose basic goal is protecting oil-gas layers from the penetration of drilling fluids by through forming temporarily plugging layers in the reservoir fracture channels,and after the drilling is completed,the plugging can release,so that the reservoirs can be effectively exploited.Polymer microsphere particles are a new type of environmentally friendly plugging material and have received widespread attention in recent years,due to their structual characteristcs,viscoelasticity etc.However,the poor thermostability and salt-tolerance of polymer limit their plugging effects under the harsh conditions of deep formations.For these problems,in this paper,the organic modified montmorillonite(O-Mt)was used as a reinforcing agent and filled in the terpolymer matrix(PAAA)synthesized by in-situ inverse suspension polymerization of acrylamide(AM),acrylic acid(AA),2-acrylamido-2-methylpropanesulfonic acid(AMPS)to manufacture an excellent performance polymer/nanocomposites(PAAA/O-Mt).The preparation conditions were optimized,and the effects of O-Mt platelets on the structure,morphology and thermostability of the nanocomposites were studied through FTIR,XRD,PSD,SEM,TEM and DTG-TGA.The experimental results shown that O-Mt platelets had excellent dispersion in PAAA matrix and exhibited an exfoliated structure.At the same times,the microsphere morphology and thermostability of the terpolymer were significantly improved.In addition,the water swelling of pure PAAA and PAAA/O-Mt nanocomposites was investigated thorough tea bag immersion experiment,and the plugging ability of microsphere materials was evaluated by multi-function core plugging instrument.The test results suggested that the introduction of O-Mt exhibited a significant improvement on the swelling behavior and plugging performance of nanocomposites.Among them,the plugging rate of PAAA/O-Mt nanocomposites containing 2.0 wt.% O-Mt layers reached at 85.8%.Throughout the reverse displacement experiment,it was found that the plugging layers formed by PAAA/O-Mt nanocomposites can be released under the flowback water,and the plugging removal rates were above 80%.Additionally,the water-based slurry filtration loss test results shown that these microsphere particles have excellent fluid loss performance.Therefore,these microsphere materials could be used as an ideal novel material to improve the oil recovery.