Polymer flooding reservoir

Visualization of technologies to improve polymer flooding reservoir related data. 

Seright, R.S. 2010. Potential for Polymer Flooding Reservoirs with Viscous Oils. Paper SPE 129899 presented at the SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, USA, 24-28 April. 

Liu, C., Weilin, Y., Qingshan, Y., and Hongyu, M. 2010. Logging Response Characteristic Analyses and Saturation Calculation Method for Polymer Flooded Reservoir. Paper SPE 131472 presented at the International Pil and Gas Conference and Exhibition In China, Beijing, 8-10 June. DPI 10.2118/131472-MS. 

Polymer Flooding. Even in the absence of fractures and thief 2ones, the volumetric sweep efficiency of injected fluids can be quite low. The poor volumetric sweep efficiency exhibited in waterfloods is related to the mobiUty ratio, Af, the mobiUty of the injected water in the highly flooded (low oil saturation) rock, divided by the mobiUty of the oil in oil-bearing portions of the reservoir, (72,73). The mobiUty ratio is related to the rock permeabihty to oil, and injected water, and to the viscosity of these fluids by the following equation ... 

Eig. 3. This polymer flooding method requites a preflush to condition the reservoir, the injection of a polymer solution for mobihty control to niinimi2e... 

A second field evaluation of the ASP process has been initiated in Wyoming. Additionally, an ASP field project has been designed for the Peoples Repubhc of China. The appHcability of the ASP process to a variety of reservoirs has yet to be fully determined. AppHcation of alkali and alkali polymer flooding has been limited to cmde oils having discernible acid numbers, wherein the alkali produced cmde oil soaps which in combination with alkali resulted in providing low interfacial tensions. The ASP process appears to be suitable for cmde oils with nil acid numbers (177), and hence should have broad apphcabdity. 

The state of the art in chemical oil recovery has been reviewed [1732]. More than two thirds of the original oil remains unrecovered in an oil reservoir after primary and secondary recovery methods have been exhausted. Many chemically based oil-recovery methods have been proposed and tested in the laboratory and field. Indeed, chemical oil-recovery methods offer a real challenge in view of their success in the laboratory and lack of success in the field. The problem lies in the inadequacy of laboratory experiments and the limited knowledge of reservoir characteristics. Field test performances of polymer, alkaline, and micellar flooding methods have been examined for nearly 50 field tests. The oil-recovery performance of micellar floods is the highest, followed by polymer floods. Alkaline floods have been largely unsuccessful. The reasons underlying success or failure are examined in the literature [1732]. 

Alkaline/surfactant/polymer compositional reservoir simulator, 3-dimensional compositional reservoir simulator, for high-pH chemical flooding processes [178]... 

G. Ma. Laboratory study on polymer flooding in oil reservoir with high salinity. Oil Gas Recovery Technol, 3(2) I,1, 33,1996. 

Early researchers sought to choose appropriate surfactants for mobility control from the hundreds or thousands that might be used, but very little of the technology base that they needed had yet been created. Since then, work on micellar/polymer flooding has established several phase properties that must be met by almost any EOR surfactant, regardless of the application. This list of properties includes a Krafft temperature that is below the reservoir temperature, even if the connate brine contains a high concentration of divalent ions (i.e., hardness tolerance), and a lower consolute solution temperature (cloud point) that is above the reservoir temperature. 

Many of the basic concepts of micellar-polymer flooding apply to alkaline flooding. However, alkaline flooding is fundamentally different because a surfactant is created in the reservoir from the reaction of hydroxide with acidic components in crude oil. This reaction means that the amount of petroleum soap will vary locally as the water-to-oil ratio varies. The amount of petroleum soap has a large effect on phase behavior in crude-oil-alkali-surfactant systems. 

A number of laboratory studies of the application of the alkali-surfactant-polymer flooding to various reservoir systems have been reported (63-67), but field application of this technology has been limited. Several field pilots are in progress or have been completed, but only one has been evaluated to date in the technical literature (68). This project is in the West Kiehl field in Wyoming operated by Terra Resources Inc. 

Micellar-polymer flooding and alkali-surfactant-polymer flooding both rely on the injection into a crude-oil reservoir of surfactants or surfactantforming materials. Emulsions may be injected into the reservoir, or they may be formed in the reservoir, but their properties will change as they travel through the reservoir to eventually flow from a producing well after weeks or months. 

Surfactant-polymer flooding involves successive injections into the reservoir of an aqueous surfactant-cosurfactant solution and a dilute aqueous solution of a high molecular weight polymer. The primary purpose of the surfactant slug is to reduce the interfacial... 

C. Tielong, S. Zhengyu, F. Song et ah, A Pilot Test of Polymer Flooding in Reservoir, In... 

Another measure of the success of chemical EOR is the amount of chemical injected in pounds per barrel of incremental oil produced (Ib/bbl), or tons of oil produced per ton of chemical injected, a figure often used in China to represent polymer flooding efficiency. Chang et al. (2006) reported that incremental oil recovery factors of up to 14% of the OOIP have been obtained in polymer flooding good-quaUty reservoirs, and incremental oil recovery factors of up to 25% of OOIP have been reported in ASP pilot areas. 

A publication that specifically focuses on the screening criteria for chemical processes has not been seen in the literature. Screening criteria for broader EOR processes have been discussed by several researchers—for example, Taber et al. (1997a, 1997b), Al-Bahar et al. (2004), and Dickson et al. (2010). This section briefly summarizes several critical parameters regarding chemical EOR application conditions. Many parameters could affect chemical EOR processes however, the most critical parameters should be reservoir temperature, formation salinity and divalent contents, clay contents, and oil viscosity. Eor polymer flooding, permeability is another critical parameter. 

Bei-l-Qu-Duan-Xi was the first large-scale polymer flooding field application in the northern Saertu field, Daqing. There were 25 injectors and 37 producers in the test area in five-spot patterns. The target layers were PI1.4. The well spacing from injector to producer was 250 to 300 m. Some of the reservoir and flnid data are shown in Table 5.22 (Chang et al., 2006 Yan et al., 2006). 

Most of polymer floods in Daqing were conducted in oil zones. There are a significant amount of reserves in transition zones. In 1995, the Sabei transition zone was selected for a polymer flooding pilot test. The target formation was PI1.4. The basic reservoir, fluid, and well data are shown in Table 5.24 (Niu et al., 2006). The well pattern was irregular four-spot. 

Polymer Flooding in a High-Temperature and High-Salinity Reservoir... 

To establish a baseline for the alkaline-polymer flooding, the operator used several empirical correlations and reservoir simulation to estimate the water-flood recovery factor, which was 50%. To study residual oil saturahon distribution, the operator used several approaches such as pressure coring, C/O logging, core wafer, and waterflood performance analysis. Finahy, all data were integrated into a simulahon model to output the residual oil saturation distribuhon. The average residual oil saturahon was 0.33. The gas cap shrank and existed only in the north area to Wells X19 and X35. This area was far away from the AP flooding area so that it was not affected by AP. 

Davison, R, Mentzer, E., 1980. Polymer flooding in North Sea reservoirs. Paper SPE 9300 presented at the SPE 55th Annual Fall Conference, Dallas, 21-24 September SPEJ (June 1982), 353-362. 

Potts, D.E., Kuehne, D.L., 1988. Strategy for alkaline polymer flood design with Berea and reservoir-rock corefloods. SPERE 3 (4), 1143-1152. 

Vela, S., Peaceman, D.W., Sandvik, E.I., 1976. Evaluation of polymer flooding in a layered reservoir with crossflow, retention and degradation. SPEJ (April), 82-96. 

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