The research on the mechanism of repeated fracturing fractures shows that the pressure drop caused by the initial fracturing fractures and the production activities of the oil layer in the repeated fracturing wells leads to changes in the stress field near the well, which causes the fractures to re-fract during the repeated fracturing process. Combining with the low permeability characteristics of Tongxi fault block reservoir in North China Oilfield, optimization of repeated fracturing parameters and selection of fracturing materials were carried out, and the principle of well selection and layer selection was put forward. The repeated fracturing technology was successfully implemented in the Tong47-43x well and achieved a good oil-increasing effect, which provided important technical measures for the next development of the Tongxi fault block reservoir.

In the process of oilfield waterflood development, the rate of water injection is an important embodiment of water injection management level, which is an important parameter that not only reflects the formation capacity, but also reflects the production capacity of water injection equipment. Because of the influence of injection water quality, production environment, management level and other factors, the water injection flowmeter needs to be calibrated regularly to ensure the accuracy of measurement in the actual water injection process. In Huabei Oilfield, the flowmeters used in the production are removable for calibration, which has problems such as the difficulties when dismantling and mounting the flowmeters for calibration outside, easily being damaged in transit and low calibration efficiency. In order to solve above problems, a set of on-line calibration skid-mounted device for water injection flowmeter is developed, which realizes on-line calibration for water injection flowmeter and meets the actual demands of water injection flowmeter calibration in oil field.

A series of new anionic-nonionic surfactants, biophenol polyoxyethylene ether carboxylate (BPPC), were synthesized using biophenol as raw material. The chemical structure of anionic-nonionic surfactant was determined by Fourier transform infrared spectroscopy and elemental analysis. The effects of concentration and degree of polymerization on surface tension were investigated. These new surfactants have good surface activity. The critical micelle concentration (cmc) is 9.30 × 10−3 mol/L, 8.50 × 10−3 mol/L, 8.10 × 10−3 mol/L, and 7.71 × 10−3 mol/L. The corresponding surface tensions at CMC are 28.38. mN/m, 28.60 mN/m, 30.40 mN/m, and 30.00 mN/m. Then focus on the foaming properties of BPPC. The results showed that the concentration of surfactant and Ca2+/Mg2+ had certain effects on the foaming properties and foam stability of cashew nut-based surfactants. Due to the relatively good foam properties of BPPC, it has broad application prospects in detergents and petroleum recovery.

Four kinds of biological phenolamine resin block ethers (BPPC) surfactants with different molecular weights were synthesized from biological phenol, formaldehyde and polyvinyl polyamines. The structure of BPPC was characterized by Ft-ir and H NMR. The surface properties of BPPC polyether surfactant and the change curve of surface tension with concentration in aqueous solution at different temperature were studied by surface tension method. The results showed that the critical micelle concentration (cmc) of BPPC and the γcmc increased with the increase of EO content. With the increase of molecular weight, number of branched chains and length of branched chains, cmc and γcmc decreased. The thermodynamic calculation results show that BPPC shows enthalpy/entropy compensation during micellization in aqueous solution. The compensation temperature T was all (300±2) K, and with the increase of molecular weight, number of branched chains and length of branched chains, the stability of BPPC formed in aqueous solution was enhanced.

In order to screen out the optimal microemulsion oil drive system, the effect of micro emulsion performance on the residual oil of pore is selected, and the remarkable effect of improving recovery rate is proved from both macro and micro aspects by analyzing the fissure core oil drive experiment and the distribution law of the residual oil of the pore. The results showed that the best microemulsion system is made of positive octane 8mL, water 8mL, 4.5% mass fraction of the beetroot, 6% mass score of positive butanol, 5% quality score of NaCI. And that microemulsion system has a smaller particle size distribution range, higher viscosity, strong stability and a smaller proportion of pore residual oil.