import numpy as np
def a(df1):
    start = 0
    for index, value in df1['дата'].items():
        b = index + 1
        df1['дата2'] = np.where(df1['№ Скважины'][index] == df1['№ Скважины'][b] and monthdelta(df1['дата'][index], df1['дата'][b]) >= 2, (value+relativedelta(months=1)), np.nan)
        df1 = df1.reset_index(drop=False)
        start+=1
        df1 = pd.lreshape(df1, {'дата': ['дата', 'дата2']})
        df1 = df1.sort_values(by='index')
        df1 = df1.drop('index', axis=1)
    return df1