Synthesis And Application Of High-Performance Deflection Fracturing Materials

Targeting on the current issues of deflection fracturing materials used in oil fields,which are low effectiveness,easy to fail,causing great damage to the reservoir,and being easily affected by the reservoir environment,a deflection fracturing material was prepared and carried out by this paper.Its physical and chemical characterization,optimization of synthesis conditions,application performance evaluation and field test evaluation are conducted followingly.It is verified that the material can meet the development requirements of having high plugging strength,excellent temperature resistance,degradability,and low residue,which hold value in large-scale using.The main research work and understanding of this paper are as follows:(1)Using maleic anhydride,styrene,and acrylic acid as monomers,azobisisobutyronitrile as initiator,a ternary polymerization product was prepared by free radical solution polymerization.The functional groups of the synthesized products were confirmed by FT-IR and 1H NMR tests.The molecular weight,Zeta and nanoparticle size analysis,conversion rate,glass transition temperature,density and hydrolysis performance tests of the products in different experimental groups are conducted.The reaction conditions are optimized to reach the most optimal reaction conditions:monomer molar ratio 1:1:1,total monomer mass fraction 14%,initiator mass fraction 0.5%,reaction temperature 65?.Under those conditions,the product molecular weight is 105471,Zeta potential is relatively small,the distribution of particle size is uniform,the glass transition temperature is 334?,the density is 1.013 g/cm3,with the highest hydrolysis rate of 93.72%.(2)The compatibility performance of synthetic materials with simulated formation water and different fracturing fluid systems are tested.The plugging performance of the materials to natural cores is tested.Physical-simulated deflection fracturing experiment is conducted,for observing and analyzing the hydrolysis process of synthetic materials.The results show that the material has a good compatibility with oilfield fluids;the material can lower the permeability of different cores to under 9×10-3 ?m2,and the maximum plugging rate is 91.05%.After the material is hydrolyzed,the core permeability is restored to more than 94%,and the plugging performance is excellent;in the physical-simulated deflection fracturing experiment,the new material can successfully seal the old cracks and press out new ones,the fracture pressure is increased by 4.02 MPa;the proportion of the product hydrolyzed residue is less than 5%,and the distribution of particle sizes is 2-4 ?m.(3)Onsite application tests are conducted on the synthetic materials.Old fractures were successfully sealed,and new fractures were opened.After the construction of the test wells,the daily oil production increased by 4.4 t,0.9t,1.2t,and with moisture content decreased to 34.9%,82%,69%,respectively.The moisture content declines steadily,and the deflection fracturing is a success.The synthetic materials holds practical production and application value.