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H59 block in Jilin Oilfield was selected as a pilot site for CCS (carbon capture and storage) project. The block is of a light oil reservoir with average permeability of 3.5 mD and well-developed natural fractures. CO 2 separated from a nearby natural gas reservoir was injected into the oil block during six years operation, with nearly 0.26 million tons of CO 2 (0.32 HCPV) has been injected. In order to evaluate the miscibility effect of CO 2 flooding, injection and well production data were analyzed, including injection pressure, bottom hole flowing pressure (BHFP) of producer wells, CO 2 breakthrough time and produced oil and gas compositions. Reservoir pressure distribution during CO 2 injection was figured out based injection pressure and BHFP using the Kriging interpolation method, and the varying miscible region was illustrated in pressure contours. The analysis results show that CO 2 injection can significantly increase oil production, but the size of the miscible region can be greatly reduced after early CO 2 breakthrough, which can cause BHFP and oil production declining. In comparison with the experimental data of core flooding with CO 2 at different modes, the produced oil composition data indicate that CO 2 flooding in the field was more likely in near miscible or immiscible modes, though the injection pressure was higher than the MMP, which can be attributed to unexpected early CO 2 breakthrough and low permeability nature of the reservoir.

This article presents a convenient method for synthesizing segmented poly(ether ester amide)s (PEEAs) by polycondensation and chain extension. A nylon-6 oligomer prepared from e-caprolactam and ethanolamine through ring-opening polymerization was polymerized with adipic acid and diglycol to prepare PEEA prepolymers (PrePEEAs) with ether linkages and amide contents ranging from 20 to 60 mol%. Chain extension of the PrePEEAs was conducted at 200°C using 2,2′-(1,4-phenylene)-bis(2-oxazoline) and carbonyl biscaprolactamate as combination chain extenders. The chain-extended PEEAs (ExtPEEAs) were characterized by viscometry, gel permeation chromatography, FT-IR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray diffraction, and tensile testing. Results show that incorporation of nylon-6 segments yields semicrystalline ExtPEEAs and that introduction of ether linkages improves the flexibility of the resultant polymers. ExtPEEAs showed Tm from 107.6 to 137.3°C, good thermal stability with initial decomposition temperatures above 337.3°C, and tensile strengths of up to 27.4 MPa with strains at break ranging from 231.24 to 1052.52%. POLYM. ENG. SCI., 55:763–770, 2015. © 2014 Society of Plastics Engineers