Petroleum Science >2012,??Issue 4:??417-428 DOI: https://doi.org/10.1007/s12182-012-0229-2
Comparison of basic features and origins ofoolitic shoal reservoirs between carbonateplatform interior and platform margin locationsin the Lower Triassic Feixianguan Formation ofthe Sichuan Basin, southwest China Open?Access
文章信息
State Key Laboratory of Oil and Gas Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China 2 School of Resource and Environment, Southwest Petroleum University, Chengdu, Sichuan 610500, China;3 Branch of Exploration Management, PetroChina Southwest Oil and Gas Field Company, Chengdu, Sichuan 610051, China;4 Branch Station in Research Institute of Petroleum Exploration and Development, Post-doctoral Workstation of PetroChina Southwest Oil and Gas Field Company, Chengdu, Sichuan 610051, China;5 Branch of Exploration Industry, PetroChina Southwest Oil and Gas Field Company, Chengdu, Sichuan 610051, China;6 Department of Earth Sciences, Nanjing University, Jiangsu 210093, China;2 School of Resource and Environment, Southwest Petroleum University, Chengdu, Sichuan 610500, China;2 School of Resource and Environment, Southwest Petroleum University, Chengdu, Sichuan 610500, China;2 School of Resource and Environment, Southwest Petroleum University, Chengdu, Sichuan 610500, China;2 School of Resource and Environment, Southwest Petroleum University, Chengdu, Sichuan 610500, China
文章摘要
the Sichuan Basin of southwest China are an important target for gas exploration in the basin. Their
occurrence, like other cases worldwide, can be divided into two locations in general, i.e., platform interior
and platform margin locations. Their differences of reservoir features and origins, however, have not been
investigated comprehensively due to different exploration degrees. This issue is addressed in this paper, to
provide basic data and information for the basin’s hydrocarbon exploration and for the study of carbonate
platform sedimentology and reservoir geology worldwide. We compared the features of these two types
of reservoirs in detail, including the depositional and diagenetic features, pore types and petrophysical
features. Based on the comparison, the origin of the reservoirs was further discussed. It is shown that the
reservoirs in platform interior and platform margin locations differ significantly. The interior carbonates
were deposited in moderate to high energy settings and the dominant lithologic type was limestone,
which was weakly compacted and intensely cemented and has undergone meteoric dissolution. Pore types
include intragranular dissolution and moldic pores, with low porosities (<6%) and low permeabilities
(<0.1 mD). By contrast, the platform margin carbonates were deposited in relatively high energy
settings and mainly consisted of dolostones with some limestones. The rocks were strongly compacted
but incompletely cemented. As a result, some primary intergranular pores were preserved. Both
meteoric solution and burial solution have taken place. There are various types of pore spaces including
intergranular and intercrystalline solution pores and residual intergranular pores. This type of reservoir
generally has better petrophysical properties (>9% porosity and >0.1 mD permeability) and pore-throat
structures than the interior reservoirs. These differences were influenced by both primary depositional
features and secondary diagenesis. For the interior carbonate reservoirs, early meteoric dissolution, weak
compaction and strong cementation are important controlling factors. By contrast, the factors controlling
the formation of the margin carbonate reservoirs mainly include dolomitization, preservation of primary
pores and burial dissolution.
關鍵詞
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Carbonate platform, oolitic shoal reservoir, platform margin, platform interior, LowerTriassic, Feixianguan Formation, Sichuan Basin, China