oasis contract imbalance update updated imbalances per contract total historical current mth cumul 201 k 12 807 8 181 20 988 202 k 13 951 7 879 6 072 203 k 6 152 267 6 419 204 k 27 392 6 306 21 088 total 5 516 6 875 12 391 due oasis