Figure 10 Fracture traces of the Oligocene Shangganchaigou Formation on Formation MicroImaging log, A1 well, Shizigou oil field. Dark linear features on the unwrapped image of the borehole wall mark conductive fracture traces of different set orientations in bedded carbonates. See Figure 5

Figure 17 Microfractures of the Oligocene Shangganchaigou Formation in a horizontal thin section from the A1 well, Shizigou oil field. The host rock is argillaceous limestone; depth, 4004 m (13,136 ft). Letter A indicates earlier fracture filled with gypsum; letter B, later open fracture filled

Fig. 3. ( a ) Rose diagrams of the paleocurrent indicators for the Lulehe Formation, Xiaganchaigou Formation, and Shangganchaigou Formation. ( b ) Hubs occurrence of the slump structure of the studied sedimentary sequence. N , number of samples.

Figure 6. Representative seismic profile B–B′ across the northern Qaidam basin. (A) Uninterpreted. (B) Interpreted. The location of this seismic profile is shown in Figure 3 . Q—Quaternary; SZ—Shizigou Formation; SY—Shangyoushashan Formation; XY—Xiayoushashan Formation; SG—Shangganchaigou

—Shangyoushashan Formation; XYSS—Xiayoushashan Formation; SGCG—Shangganchaigou Formation; XGCG—Xiaganchaigou Formation.

Figure 3 Structural cross section based on surface geology and seismic data. The line location is shown in Figure 1B . , Paleocene Lulehe Formation; , Eocene Xiaganchaigou Formation; , Oligocene Shangganchaigou Formation; , Miocene Xiayoushashan Formation; , Miocene Shangyoushashan

Figure 8. (A) Uninterpreted and (B) interpreted versions of a three-dimensional seismic section across the northern Shizigou salt structure. See Figure 5 for location. E 3 2 = Upper Xiaganchaigou Formation; N 1 = Shangganchaigou Formation; N 2 1 = Xiayoushashan Formation.

Figure 9. (A) Uninterpreted and (B) interpreted versions of a three-dimensional seismic section across the middle of the Shizigou salt structure. See Figure 5 for location. E 3 2 = Upper Xiaganchaigou Formation; N 1 = Shangganchaigou Formation; N 2 1 = Xiayoushashan Formation.

Figure 10. (A) Uninterpreted and (B) interpreted versions of a three-dimensional seismic section across the southern Shizigou salt structure. See Figure 5 for location. E 3 2 = Upper Xiaganchaigou Formation; N 1 = Shangganchaigou Formation; N 2 1 = Xiayoushashan Formation.

Figure 14. Seismic section 1 showing a typical strike-slip flower structure in the Yingxiongling range, where salt is absent. See Figure 2 for location. E 3 2 = Upper Xiaganchaigou Formation; N 1 = Shangganchaigou Formation; N 2 1 = Xiayoushashan Formation.

Figure 11. (A) Uninterpreted and (B) interpreted versions of a three-dimensional seismic strike section across the hanging wall of the Shizigou salt structure. See Figure 5 for location. E 3 2 = Upper Xiaganchaigou Formation; N 1 = Shangganchaigou Formation; N 2 1 = Xiayoushashan Formation.

Figure 12. (A) Uninterpreted and (B) interpreted versions of a three-dimensional seismic strike section across the hanging wall and footwall of the Shizigou salt structure. See Figure 5 for location. E 3 2 = Upper Xiaganchaigou Formation; N 1 = Shangganchaigou Formation; N 2 1

of the Xiaganchaigou Formation. (D) Meandering fluvial-lacustrine deposits of the Shangganchaigou Formation. (E) Braided fluvial deposits of the Shangyoushashan Formation.

Figure 18 The relationship between the gypsum content and the proportion of all filled fractures in the Oligocene Shangganchaigou Formation from one borehole of cores, Nanyishan field structure. The gypsum beds are above layer A. In section A, 67% of the fractures are filled; in section B, 25

Figure 12. Interpreted seismic profile (1) in time domain. T0 to T6 are regionally correlative reflectors; T0 at the top of the Shizigou Formation, T1 at the top of the Shangyoushashan Formation, T2 at the top of the Xiayoushashan Formation, T3 at the top of the Shangganchaigou Formation, TR

Figure 6 The surface of the high-angle small fault (shear fracture) in the core of the Oligocene Shangganchaigou Formation from the vertical well, Nanyishan gas field, limestone; depth, 3031.5 m (9945.9 ft). Calcite and striations mark the fracture surface (arrow in slip direction). The top

. Shangganchaigou Formation, 4523 m. (K) Upward-coarsening packages of sandy siltstone to fine sandstone. Shangganchaigou Formation, 3659.7 m. (L) Horizontally bedded clast-supported pebble-cobble conglomerate interbedded with coarse- to very coarse-grained sandstone. Shangyoushashan Formation, 5603 m.

. Shangganchaigou Formation, 4523 m. (K) Upward-coarsening packages of sandy siltstone to fine sandstone. Shangganchaigou Formation, 3659.7 m. (L) Horizontally bedded clast-supported pebble-cobble conglomerate interbedded with coarse- to very coarse-grained sandstone. Shangyoushashan Formation, 5603 m.

Figure 2B . (B–D) Sketches illustrating the influence of fault slip alone (C) are inspired by Suppe and Medwedeff (1990) and the combined effects of fault slip and buckling in the limb (D) on long-term topographic growth. F1—Shizigou fault; LOS—line of sight; SG—Shangganchaigou Formation; UXG—Upper

Formation; XYSS—Xiayoushashan Formation; SGCG—Shangganchaigou Formation; XGCG—Xiaganchaigou Formation.