| Author's Name: ZHENG Jianfeng1,2,3, ZHU Yongjin1,2,3, ZHANG Benjian2,3,4, SUN Chonghao2,3,5,
LI Wenzheng1,2,3, WU Dongxu1,2,3, ZHOU Jingao1,2,3 |
| Institution: PetroChina Hangzhou Research Institute of Geology;State Energy Key Laboratory of Oil and Gas in Carbonate Strata;Key Laboratory of Carbonate Reservoirs, CNPC;PetroChina Southwest Oil & Gas Field Company;PetroChina Tarim Oilfield Company |
| Abstract: |
| With the continuous expansion of oil and gas exploration into ultra-deep and ancient strata in the three major
marine cratonic basins, challenges such as unclear favorable exploration zones have emerged. Therefore it is imperative to
deepen research on depositional models for critical geological periods. Based on the summary of the NeoproterozoicPaleozoic tectonic-sedimentary differential evolution characteristics of the three major basins, this paper analyzes the
controlling effects of tectonic differentiation on sedimentary evolution. It is pointed out that the three ancient marine
cratonic basins exhibit a tectonic differentiation pattern of "rift-depression-uplift", driving carbonate platforms
undergoing an evolutionary cycle of "isolated platform-ramp-rimmed platform", and the formation and evolution of rifts
control the sedimentary differentiation of platforms and the similarity of the vertical sourced-reservoer-cap assemblages.
Four new models of carbonate sedimentation were established: "multi-type platform margins" and "double shoals" ramp
models, carbonate-gypsum/salt symbiotic system model, fault terrace platform margin model of Dengying Formation in
Sichuan Basin, and continuously expanding platform margin sedimentary model of Cambrian in Tarim Basin. The "multitype platform margins" and "double shoals" ramp model reveal that the continental margin and rift margin, depression
margin, paleo-uplift of inner ramp and lagoon periphery are favorable mound-shoal development areas. The carbonategypsum/salt symbiotic system model reveals that the margin of the paleo-uplift during transgression period is a favorable
shoal development area. The fault terrace platform margin sedimentary model indicates that multiple syndepositional fault
systems control the formation of step-like platform margins of the 2nd member of Dengying Formation in Sichuan Basin,
with thick mound-shoal complexes developed on high fault blocks. The continuous extension platform margin
sedimentary model reveals that the Cambrian platform margin belt of Lunnan-Gucheng area in Tarim Basin has
undergone the evolution of mud-rich ramp→low-angle progradational ramp/weakly rimmed platform→vertically
aggrading platform→laterally prograding rimmed platform. The new understanding of carbonate sedimentary models
confirms that the mound-shoal belts around the paleo-rift of the three ancient marine craton basins are still important
areas for increasing oil and gas reserves and ensuring resource succession. In addition, new fields such as gravity flow
deposits in slope facies and marlstones in evaporative lagoon facies are worthy of exploration. The establishment of the
new models of carbonate sedimentation strongly supports the deployment of oil and gas exploration, and also provides a
new direction and ideas for future exploration. |
| Keywords: marine craton; tectonic-depositional evolution; carbonate rock; sedimentary model; Neoproterozoic-Paleo⁃
zoic; exploration area |
|
投稿时间：
2008-06-11 |
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