Core flood test

In general, chelating agents possess some unique chemical characteristics. The most significant attribute of these chemicals is the high solubility of the free acids in aqueous solutions. Linear core flood tests were used to study the formation of wormholes. Both hydroxyethylethylene diaminetriacetic acid and hydroxyethyliminodiacetic acid produced wormholes in limestone cores when tested at 150° F. However, the efficiency and capacities differ. Because these chemicals have high solubility in the acidic pH range, it was possible to test acidic (pH less than 3.5) formulations [644]. 

Berea core flood test results (Table VIII) suggested that the presence of DMAEMA improved the permeability damage characteristics of 80% NVP copolymers. The kerosene flow rate... 

Conduct core flood tests with the polymer solution at different injection rates. Measure the pressure drop, Ap, corresponding to each injection rate (velocity u). The core permeability and porosity are measured before the core flood tests. 

When comparing the viscometric and core flood data, the reader should be reminded that several factors could lead to incorrectly estimated values of Tipp in the core flood tests. The polymer may be adsorbed and retained in the porous media, or there is microgel, which would lead to reduced permeability. Thus, if the permeability reduction is not considered, the estimated Papp using the Darcy eqnation conld be higher than the actual viscosity values because the shear rate is underestimated (see Eq. 5.25). There is also the slip effect (Sorbie, 1991), which occnrs in a low-shear regime and in a low-concentration polymer... 

The difference between Eqs. 7.84 and 7.85 is that the Darcy velocity is used in Eq. 7.84, whereas the pressure gradient and permeability are used in Eq. 7.85. When core flood tests were run at a constant velocity (thus, a constant v a/a), it appeared that the oil recovery increased for those rocks with lower permeabilities (Taber et al., 1973). Clearly, the higher recovery was not a... 

Core flood tests were conducted to compare the performance from the surfactant-polymer option and polymer injection option at different injection schemes. The formula selected for use in the core flood was 0.3 wt.% SLPS -F 0.1 wt.% cosurfactant + 1500 mg/L HPAM. For this formula, the chemical cost was about 2.6/bbl incremental oil. The final selected injection scheme in the pilot is presented in Table 9.4. According to this scheme, the... 

Example 10.2 Scale the Laboratory Core Flood Test in Example 10.1 to a Field Test... 

Suppose we have run a core flood test and confirmed the parameters in Example 1 0.1. Now we want to plan a field pilot. Assume the well spacing is 100 m, and the field injection rate is the same as that used in the core flood test (1 ft/day). Find out the wt.% minimum injection concentration for the pilot. 

Core flood tests were used to compare polymer flood only and alkaline-polymer performance. To model in situ oil/water viscosity ratio correctly, the operator mixed the crude oil with kerosene at a ratio of 100 26. Single-, double-, and triple-column tests were conducted. In the single-column tests, polymer flood increased sweep efficiency over waterflood by 5.6 to 9.77%, and AP flood increased by 13.7 to 19.3%. On average, AP outperformed polymer flood by 8.8%. In the double- and triple-column tests, AP recovery factors were about 18 to 20% higher than waterflood recovery factors. Half of the incremental recovery came from the low permeability column. 

One natural core was used to compare the performance of waterflood (W), AP flood, and ASP flood. The recovery factors for W, AP, and ASP were 50%, 69.7%, and 86.4%, respectively. These core flood tests were history matched, and the history-matched model was extended to a real field model including alkaline consumption and chemical adsorption mechanisms. A layered heterogeneous model was set up by taking into account the pilot geological characteristics. The predicted performance is shown in Table 11.3. In the table, Ca, Cs, and Cp denote alkaline, surfactant, and polymer concentrations, respectively. After the designed PV of chemical slug was injected, water was injected until almost no oil was produced. The total injection PV for each case is shown in the table as well. The cost is the chemical cost per barrel of incremental oil produced. An exchange rate of 7 Chinese yuan per U.S. dollar was used. From... 

Ye and Peng (1995) measured ASP solution/oil relative permeabilities based on the preceding principle. They first conducted a core flood test using an ASP solution and calculated the Darcy viscosity for the solution, which included the polymer permeability reduction factor. Then they conducted ASP/... 

Linear and radial core flood tests were conducted to determine the polymer concentration for mobility control requirement. Figure 13.39 shows Brookfield (UL adapter) viscosity properties for the Alcoflood 1275A polymer in injection water and in an alkaline-surfactant solution. Note that the AS dramatically decreased the viscosity, and a higher polymer concentration was required to provide the same viscosity. 

Salinity was found to decrease foam stability. The surfactant concentrations in which foaming ability increased with concentration were 0 to 0.5%. The optimum polymer molecular weight for foaming ability was around 17 million. Core flood tests showed that ASPF incremental oil recovery factor over ASP was above 10% because the ASPF sweep efficiency was higher than the ASP efficiency. 

Most of the research on foam sensitivity to oils in porous media, whether in microvisual or core-flood tests, has been concerned with water-wetted pore and throat surfaces. Because petroleum reservoirs are frequently of intermediate, mixed, or oil wettability, it is of considerable interest to understand how rock wettability influences foam stability. 

Eylander used core flood tests to predict filter cake properties. Equations 23 and 24 can be used to determine the injections well s half time (a = 0.5). Eylander, however, suggested further research is needed to better determine the invasion depth, D. 

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