Fig. 3
Lithofacies identification results of the F4 Formation in the Z oilfield: (a) gray‒black mudstone facies, well Z5, at a depth of 1435.25–1435.3 m; (b) mudstone conglomerate facies with massive bedding, well Z3, at a depth of 1371.45–1371.55 m; (c) sand–mudstone interbedded facies, well Z1, at a depth of 1353.33–1353.41 m; (d) siltstone facies with parallel bedding, well Z5, at a depth of 1353.87–1353.96 m; (e) siltstone facie with wavy bedding, well Z1, at a depth of 1355.33–1355.41 m; (f) siltstone facies with cross bedding, well Z5, at a depth of 1429.21–1429.29 m; (g) massive siltstone facies, well Z1, at a depth of 1352.1–1352.21 m; (h) fine sandstone facies with wavy bedding, well Z7, at a depth of 1456.27–1456.1 m; (i) massive fine sandstone facies, well Z2, at a depth of 1354.25–1354.4 m; (j) massive medium sandstone facies, well Z6, at a depth of 1462.35–1462.43 m; (k) massive coarse sandstone facies, well Z8, at a depth of 1366.33–1366.38 m; and (l) grain-size gradation coarse sandstone facies, well Z3, at a depth of 1341.15–1341.2 m.
