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Duan X.,China University of Petroleum - Beijing | Duan X.,China National Petroleum Corporation | Duan X.,Key Laboratory of Petroleum Engineering | Hou J.,China University of Petroleum - Beijing | And 7 more authors.
Shiyou Huagong/Petrochemical Technology | Year: 2013

Great advances have been made in foam flooding technique for the improvement of oil recovery. The research progresses in foaming agents with oil resistant stability in recent years were reviewed. The defoaming property of foam in the presence of oil and the oil resistant mechanism of the foaming agents were discussed according to the molecular structure and surface/interfacial tension of the surfactants. The superiority and limitations of several oil resistant foaming agents were analyzed. Supercritical CO2 foam and fluorocarbon surfactant foam have considerable oil resistance, but their oil resistant mechanism and application should further be studied. The main directions for the research of the future oil resistant foaming agents are effectively mixing the surfactant systems and adding proper additives. Source


Xue Y.,Key Laboratory of Petroleum Engineering | Cheng L.,Key Laboratory of Petroleum Engineering | Li C.,Key Laboratory of Petroleum Engineering
Advanced Materials Research | Year: 2012

Whether the stress sensitivity in the mid-high permeability is stronger than that in the low permeability reservoir is current hot debate, aimed at this question. 14 samples are selected to calculate the permeability loss rate separately in the laboratory simulation experiment, the results show that the absolute value of loss rate of the mid-high permeability core is higher than that of low permeability core, but the relative permeability loss rate is lower than that of low permeability core, which, namely, means the low-permeability reservoir has stronger stress sensitivity. The stress sensitivity curve in the high permeability reservoirs could be classified into the type model of "gentle", while the stress sensitivity curve in the low permeability reservoir could be concluded as the "first steep then slow " mode. Hence the bottom-hole flowing pressure must be controlled reasonably in order to keep the productivity well. © (2012) Trans Tech Publications, Switzerland. Source


Leng G.-Y.,China University of Petroleum - Beijing | Leng G.-Y.,China National Petroleum Corporation | Leng G.-Y.,Key Laboratory of Petroleum Engineering | Zhao F.-L.,China University of Petroleum - Beijing | And 12 more authors.
Oilfield Chemistry | Year: 2014

Using double-layer heterogeneous core model, fully playing advantages of profile control and oil displacement, the improving oil recovery effect of eight projects in different permeability contrast conditions was evaluated. The results showed that the water ratio decreased about 15% and oil recovery increased 6.7% and 8.3% in ASP flooding and polymer flooding respectively, when the permeability of core was 30 × 10-3/1000 × 10 3 um2. After modified-starch gel was formed, the water cut of ASP flooding declined to 44%, which was significantly less than the lowest value of polymer flooding (60%) and water flooding (70%), and the oil recovery increase was 23.5%, 19.2% and 10.1% in ASP flooding, polymer flooding and water flooding respectively. ASP flooding could effectiv start the lower permeability layer and produce better exploitation results than polymer flooding. The oil recovery increase of "modified-starch gel + ASP flooding" was 40.4%, which was better than the oil recovery sum of separately using modified-starch gel and ASP flooding (35.6%), and 4.3 percent higher than that of "chromium gel+ASP flooding". When the permeability was 30× 10 -3/2000 × 10μm2 and 30 × 10- 3/500 × 10μm2, the oil recovery increase of "modified-starch gel + ASP flooding" was 45.3% and 34.4%, and the oil recovery of ASP flooding increased 25.1% and 22.2%, respectively, which indicated that the more severe reservoir heterogeneity, the better exploitation results of combination flooding was. Source


Wang F.-G.,China University of Petroleum - Beijing | Wang F.-G.,China National Petroleum Corporation | Wang F.-G.,Key Laboratory of Petroleum Engineering | Hou J.-R.,China University of Petroleum - Beijing | And 9 more authors.
Oilfield Chemistry | Year: 2014

Aimed at the certain reservoir with formation temperature of 82°C, a comb copolymer flooding was probed, the physical and chemical properties of the comb copolymer was evaluated, such as high temperature resistance, shearing rheological property, shear stability, long term stability and salt resistance; then, dynamic flooding experiments were carried out, and the slug size, the slug concentration and the way of injection method were screened. The resulted showed that the viscosity retention rate of comb polymer solutions with the concentration of 1500-2000 mg/L was still more than 40% after aged at the temperature of 82°C for 30 days. The viscosity of comb polymer solution decreased by only 8.95 mPa · s after sheared at the speed of 1500 r/min for 120 minutes. The comb polymer had more excellent temperature resistance and salt resistance than that the common polymer and the comb polymer solution and belonged to a typical non-Newtonian fluid. The oil displacement experiments showed that the larger the slug size the more the recovery efficiency under the condition of the same slug concentration, and the higher the slug concentration the more recovery efficiency under the condition of the same slug size. The optimal slug concentration was 2000 mg/L, the optimal slug size was 0.3 PV, and the way of injection was complete injection. Source


Li S.,Petrochina | Duan X.,China University of Petroleum - Beijing | Duan X.,Key Laboratory of Petroleum Engineering | Hou J.,China University of Petroleum - Beijing | And 5 more authors.
Shiyou Huagong Gaodeng Xuexiao Xuebao/Journal of Petrochemical Universities | Year: 2014

The appropriate HLB of emulsifier was screened and evaluated, and emulsion with strong stability was selected. Static test results showed that emulsion had good resistance and salt resistance. With the increasing salinity, stable performance of the emulsion decreased slightly. The flow resistance can be improved 140 times when the liquid viscosity was high, illustrating that the emulsion system had the good displacement effect in high temperature and salinity conditions. Displacement experiments show that the matching of emulsion drops with pore throat decides transport of emulsion liquid in porous media capabilities. Source

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