Research Article

Fracture, Dissolution, and Cementation Events in Ordovician Carbonate Reservoirs, Tarim Basin, NW China

Table 2

Summary of geochemical and microthermometric characteristics of the main diagenetic features and cements shown in chronological order (paragenetic sequence). KB: matrix karstic breccia; F: fracture; V: dissolution vug; S: stylolite; Cc: calcite cement; Cs: calcite sediment; Dc: dolomite cement.

FeatureCementδ18O (VPDB)δ13C (VPDB)87Sr/86SrTh (oC)Salinity (wt.% eq. NaCl)Oil inclusionsT oil (oC)

Host rock-7.4 to -5.5-0.1 to 1.10.7088No
-7.7 to -4.7-0.3 to 1.60.7088 to 0.7089No
-6.7 to -5.9-0.6 to 1.70.7089 to 0.7090No
-8.7 to -4.3-0.6 to 3.20.70856No

Host rock cementationCc0aNo
Cc0b74 to 1501.4 to 7.7No
Cc0c75 to 1311.6 to 5.6No

Dark mottlesCs0a-9.1 to -6.3-0.5 to 1.10.7091No
Cs0bNo

F1Cc1-7.8 to -3.60.3 to 2.10.708776.9 to 113.91.9 to 2.7No
Cs1No

Karstic brecciasKB0.7099No

V2Cc2-9.1 to -4.5-3.8 to 2.274 to 1352.4 to 5.7No
F2a
F2b

S1a & S1b

F3aCc3a-11.7 to -7.1-0.2 to 2.80.7085 to 0.708860 to 1650.4 to 12.3Yellow to dull blue60 to 75
F3b

V3Cc3b-12.8 to -9.31 to 20.708550 to 1007.7 to 14.1

F4aCc4-15.8 to -13.7-0.4 to 1.70.7094 to 0.710280 to 9613.5Bright blue to green-blue
F4b
V4

F5Fluorite79 to 1129.6 to 10.5Yellow-green to green
Barite117 to 14411.1 to 19
Cc5-13.7 to -9.7-2.4 to -2.20.709061 to 97.85.7 to 14.7
Recrystallized host rock-11.1 to -6.4-1.8 to -0.1

F6Cc6-15.4 to -8.5-4.8 to -0.20.7093 to 0.709495 to 1234.7 to 10.5
V6

F7aCc7aDull blue44 to 58
F7bCc7b-18.3-1.1Light blue
V7
F7c & S2Dc1