How to remove the DC offset from the output of my op-amp integrator?
What is the reason of this -30mv DC shift?

The input offset voltage for your op-amp is +/- 0.2 mV typically but can be as high as +/- 2.5 mV. Given that your circuit has a DC gain of 201, you might see anything from +/- 40 mV to +/- 0.5 volts DC offset on the output.
Clearly, if the offset you see is only 30 mV then your model doesn't adequately represent typical values in the data sheet.