N = 50
theta = np.linspace(0, 2*np.pi, N)

x1 = np.cos(theta)
y1 = np.sin(theta)
z1 = 0.1 * np.sin(6 * theta)

x2 = 0.6 * np.cos(theta)
y2 = 0.6 * np.sin(theta)
z2 = 2  # Note that scalar values work in addition to length N arrays

fig = plt.figure()
ax = fig.add_subplot(projection='3d')
ax.fill_between(x1, y1, z1, x2, y2, z2,
                alpha=0.5, edgecolor='k')