PROFILE CONTROLLER

Profile control occurs by artificially changing the permeability as is done in water shutoff for more information, see Chapter 18. 

D. H. Hoskin, T. O. Mitchell, and P. Shu. Oil reservoir permeability profile control with crosslinked welan gum biopolymers. Patent US 4981520, 1991. 

P. Shu, C. H. Phelps, and R. C. Ng. In-situ silica cementation for profile control during steam injection. Patent US 5211232,1993. 

Chromium(III) is a commonly-used crosslinker for preparing profile control gels with polymers having carboxylate and amide functionalities (la,b). Cr(III) is applied in many forms. For example, it can be used in the form of simple chromic salts of chloride and sulfate, or as complexed Cr(III) used in leather tanning (2), or as in situ generated Cr(III) from the redox reaction of dichromate and bisulfite or thiourea. The gelation rate and gel quality depend on which form of Cr(III) is used. 

Particle Size and Desorption Rates. Bench-scale reactor studies of the desorption of toluene from single, 2- to 6-mm porous clay partides (14) showed desorption times that increased with the square of the particle radius, suggesting that diffusion controls the rate desorption. Parallel experiments performed in a small, pilot-scale rotary kiln at 300°C showed no effect of day partide size for diameters ranging from 0.4 to 7 mm. Additional single-partide studies with temperature profiles controlled to match those in the pilot-scale kiln had desorption times that were a factor of 2—3 shorter for the range of sizes studied (15). Hence, at the conditions examined, intrapartide mass transfer controlled the rate of desorption when single particles were involved and interpartide mass transfer controlled in a bed of particles in a rotary kiln. These results apply to full-scale kilns. As particle size is increased, intraparticle resistances to heat and mass transfer eventually begin to dominate. 

An interesting demonstration of profile control via alteration of the specific chemistry is that of silicon etching in C1F3 mixtures (86). Because a pure chemical (isotropic) etchant (F atoms) is combined with an ion-bombardment-controlled (anisotropic) etchant (Cl atoms), a continuous spectrum of profiles with varying anisotropies is generated by changing the gas composition. 

F. J. Doyle and F. Kayihan, Reaction profile control of the continuous pulp digester, Chem. Eng. Sci., 54, 2679-2688 (1999). 

Figure 8.8 Capillary gel electrophoresis profiles of collagen a-chains and chain polymers in 4% polyacrylamide after incubation for 4 days A) and 7 days (fl) at 30°C. Other conditions as in Figure 8.7. Note the splitting of peaks in the cr-region and the increase of y and higher chain polymers. Unincubated profile (control) is shown in Figure 8.7A. (From Deyl and MikSik, 1995, with permission.)...

There are, however, a number of species that have either photochemical lifetimes of an intermediate range or altitude profiles controlled by transport processes. Nitric acid and the peroxides are good examples of the former case, and their altitude profiles, when calculated from a purely photochemical model, may not be quantitatively correct. In the latter case, water and ozone being excellent examples, it is necessary to use measured altitude profiles that remain fixed and independent of the photochemical model. 

The incoming wafer nonuniformity may vary depending on many factors. Especially in case of Cu plating, the nonuniformity of the wafer edge is often poor. Therefore, a CMP process is required to control its polishing characteristics in accordance with the incoming wafer profile. In this section, several profile control methods are introduced as shown in Fig. 3.13. 

Figure 3.14 shows the polishing profile control by carrier design. The polishing profile of the wafer center area can be modulated by backside pressure and modification at the carrier center. The polishing profile of the... 

FIGURE 3.15 Finite element analysis result of the edge profile control achieved by changing the retainer ring design. 

The result of edge profile control by the retainer ring is shown in Fig. 3.15. The analysis is performed using the latest retainer ring design under the following conditions ... 

Figure 3.16 shows the polishing profile control by carrier and table speeds. Three cases are illustrated (1) table speed is higher than carrier speed, (2) table speed is the same as carrier speed, and (3) table speed is lower than carrier speed. Each velocity vector is shown. 

Tsujimura M, Ishii Y, Kimura N, Ota M. Polish profile control using magnetic control head. MRS 2004 Spring Meeting Unpublished. 

Bennet D et al. Real-time profile control for improved copper CMP. Solid State Technol Jun 2003. 

Siepmann J, Lecomte F, Bodmeier R. Diffusion-controlled drug delivery systems calculation of the required composition to achieve desired release profiles. / Control Release 1999 60(2-3) 379-389. 

Chemical flooding polymer, deep-formation profile control using gels, surfactant, alkaline, emulsion, foam, and their combinations... 

Luo et al (2002). The tested core permeability was 0.7 to 1.8 and the porosity was 0.2. In addition, the displaced oil was 9.5 mPa s at 70°C. Table 5.5 compares the performance of KYPAM with HPAM 1285 at a concentration of 1000 mg/L. A 0.4 PV injection volume was used. We can see that the flow behavior of KYPAM was better than HPAM 1285. KYPAM has been widely used in polymer flooding, ASP, and profile control projects in Daqing, Shengli, Huabei, and Xingjiang fields. Several field test cases are presented next. 

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