def df(self):
        """
        Makes a pandas DataFrame containing Curve data for all the wells
        in the Project. The DataFrame has a dual index of well UWI and
        curve Depths. Requires `pandas`.

        Args:
            No arguments.

        Returns:
            `pandas.DataFrame`.
        """
        import pandas as pd
        return pd.concat([w.df(uwi=True) for w in self])