Approximating a log pot would be putting an additional resistor from the
wiper to one of the ends, not across the whole pot.
Whether going across the entire pot to lower the effective total resistance may work well or may work poorly depends on how it is being used in the circuit, the reason why it "needs" to be a certain value and the power level involved. If it just a simple voltage divider to a high impedance input, for example, any value from about 1K to 1M will essentially produce the same result, even without any additional resistors, though the power dissipated by the divider itself will obviously increase as the resistance is lowered. This could easily be an issue in a battery powered circuit, for example. Pitfalls abound!
If you shared more specific details about your project, perhaps with a schematic, we can provide more specific answers.