Advanced Materials Research Vols. 807-809

Abstract: Water salinity and hardness have been regarded as main limitation for field application of polymer floods. It causes not only reduction of polymer concentration, but also injectivity loss in the near wellbore. Based on the mathematical and chemical theory, extensive numerical simulations were conducted to investigate performance of polymer floods in the high-salinity reservoirs. According to results from simulations, the high salinity reduces the viscosity of polymer in contacting area. That causes a poor sweep efficiency of polymer flooding. Moreover, the presence of divalent cations makes the project of polymer flooding worse. That is because of excessively increased bottom-hole pressure in injection well by the precipitation of polymer. The quantitative assessment of polymer floods needs to be required before field application. Therefore, the results in this paper are helpful for optimal polymer flooding design under harsh reservoir conditions.

Abstract: As polymer flooding in Daqing oil field with the further exploitation,the polymer content in the flooding produced fluids and the produced fluid flow characteristics of polymer are all constant change. The rheology of produced fluids is changed too, it obviously shows non-newtonian fluid properties. About the concentric axis of non-newtonian fluid flow rules of the air the ring,it is becoming more and more important for producted crude oil in Daqing polymer flooding oilfield. This paper built a indoor device that used for the research of Polymer flooding pumping Wells recovery liquid vertical pipe flow rules,had a deep research on flow rules and rheology of Polymer flooding pumping Wells recovery liquid that was coming from Xingbei development zone of Daqing oilfield in the tubing wellbore.

Abstract: The equation of the limit replacement width of the one-dimension two-phase flow of Bingham fluid replacing Power law fluid in eccentric annulus was established, the numerical solution method of the equation mentioned above was given and taking the 3 wells, such as the He 104-27 well etc for examples, the limit replacement widths of cement slurry displacing mud, whose rheological properties can be described as Bingham and Power law modles respectively, were calculated, by using the equation and the numerical solution method mentioned above, and compared with those of cement slurry displacing mud, whose rheological properties are all described as Binghanm modle.

Abstract: To guide the potential tapping and carry out adjustment plan, the conventional mercury injection experimental data in coring well X is analyzed by Logistic Regression analysis in SPSS 18 software. The main influence factors on reservoir producing status in the data are screened, which are the main factors from the data on microscopic pore structure; the relationship between microscopic pore structure and producing status is analyzed by capillary pressure curve and water-washing data. The result shows that, the influence of microscopic pore structure on producing status of un-tabulated reservoir is more powerful than its influence on that of tabulated reservoir; the main factor on producing status in mercury injection data of tabulated reservoir is average pore radius, the main factors on producing status in mercury injection data of un-tabulated reservoir is pore distribution peak position, permeability distribution peak value and maximum withdrawal efficiency.

Abstract: The feasibility of enhancing oil recovery in Xinjiang oilfield with heavy oil reservoir was studied. The results showed that main microbial populations in the reservoir were saprophytic, hydrocarbon-oxidizing, nitrate-reducing bacteria, sulfate-reducing bacteria, and fermentative. Given optimized carbon and nitrogen sources, the indigenous microorganisms generated gases, which mostly were CO₂, and amount of gases could reach 1.3 times volume as nutrient solution. The effect of MEOR was evaluated by a sand pack experiment, and the oil recovery was 9.5%. The test with the injection of nutrient and air was carried out. Field performance monitoring and product ion tracking results showed: 1the indigenous microorganisms were activated with the number increased 2-3, and microbial population structure changed apparently; 2The content of CO₂ and CH₄ in the gas of oil well changed slightly; 3the properties formation water were changed, the content of HCO₃^- in formation water varied greatly, and emulsion were found. 4Although Indigenous Microbial Flooding Technology may be a potential technique for the development of oilfields, that biogas generated by microbes is not the primary mechanism of Indigenous Microbial Flooding Technology is determined.

Abstract: It is well known that gel treatment has outstanding potential to delay water breakthrough and reduce water production. However, it causes the decrease of oil production by permeability reduction, even though it is not as much as reduction of water production. For this reason, to improve oil production with substantial reduction of water production, performances of gel treatments through the combination of horizontal and/or vertical wells were assessed and compared. An extensive numerical simulation was executed for four different well configurations under gel treatment associated with waterflood to accomplish the purpose of this study. Performances were compared according to cumulative oil recovery and water-oil ratio at the production well for different systems. Though all of well configurations considered in this study effectively decreased the water production compared with waterflood, applications of horizontal wells led to much higher oil recovery than vertical well because of improved sweep efficiency. Based on these results, the potential of horizontal wells was examined through different scenarios in combinations of injection and production wells. Furthermore, various well lengths of injectors or producers were assessed for horizontal wells. Because cross-flow between layers dominates performance of gel treatment, effects of vertical permeability were also investigated in application of gel treatment with horizontal well. Longer wells and higher cross-flow results in better performance. This study represents that effectiveness of horizontal wells for gel treatment even for reservoirs having dominant cross-flow.

Abstract: Situated on the piedmont tectonic belt of Tarim Basin, well KS-37 encountered large-section evaporite bed at the depth from 5100m to 5400m. Complicated geological conditions and narrow pressure safe density window prevent the cementing plug project to some degree. 2.26g/cm³ forerunner slurry, 2.26g/cm³ saturated saltwater spacer fluid aggravated by micro-manganese and 2.30 g/cm³ intumescence cement slurry, combined with corresponding technical measures have been utilized in the evaporite bed. As a result, cement plug operation has been accomplished successfully so as to meet the engineering requirements of side tracking. It is indicated based on field application that great progress has been made in the adoption of cement slurry of high density as well as corresponding technical measures, which can meet the requirements of plugging cement in evaporite bed in the condition of narrow pressure safe window.

Abstract: Right now the application of seismic attributes in China is almost only qualified. Given this situation 2D crossplot analysis, the unary linear regression method and the method of fuzzy clustering analysis are applied to get the seismic attributes from the 3D data volume of oilfield C. The seismic attributes are then quantified and the ones which are good for depicting the reservoir are found and fine depict, thus the application of the seismic attributes is more specifically. It provides good idea and method for the optimization and application of seismic attributes.

Abstract: Self-made JH4 zeoite was characterized by BET, mercury and other methods. The dynamic adsorption capacity of nC5/nC6 in light naphtha on JH4 zeolite fixed bed was investigated. The effect of cyclic purge exhaust composition, which simulate different condensation conditions, on desorption performance of JH4 zeolite bed was studied. The results shows that, the microporous BET specific surface area and pore volume of JH4 zeolite is 710.05 m2/g and 0.32 cm³/g; macropore specific surface area and pore volume is 3.64 m2/g and 0.29 cm³/g, respectively. Under the adsorption conditions of 0.1 MPa, 165 °C, adsorption capacity of n-pentane and n-hexane in light naphtha on JH4 zeolite reaches, 7.24 g/100g_ads and 3.11 g/100g_ads respectively.If the content of pentane and hexane achieves 3.68% and 0.21% in nitrogen purge gas, total desorption amount of JH4 zeolite is 2.07 g/100g_ads, falling 60.19% than that of pure N₂ purge.

Abstract: A novel kind of activated polymer flooding (APF) composing activated agent and polymer components designed for the target reservoir is studied for the first time. Interactions between the activated agent and natural surfactant from heavy oil, and the synergistic effect between the activated agent and polymer are existed. APF could enhance more oil recovery with less investment, compare to polymer-surfactant flooding (PSF) in the offshore heavy oilfield. The optimum formulation of APF is 1200mg/L polymer + 500mg/L activated agent. Experimental results implies that (1) the contained amide groups and sulfonic groups in APF can form hydrogen bonds with-NH₂ groups contained in PM, (2) the apparent viscosity of APF was higher than PM along with the increase of shear rate, (3) the viscoelasticity, deformation capability and solubility of APF were much better than PM.