Characteristics and controlling factors of the Lower Cambrian Longwangmiao Formation reservoirs in easternSichuan Basin and its adjacent areas
Ren Ying1,2, Zhong Dakang1,2, Gao Chonglong1,2, Sun Haitao1,2,Meng Hao1,2, Hu Xiaolin3, Jiang Zhenchang1,2, Wang Ai1,2
1 College of Geosciences,China University of Petroleum(Beijing),Beijing 102249
2 State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum(Beijing),Beijing 102249
3 Guizhou Natural Gas Energy Investment Co., Ltd., Guiyang 550081, Guizhou
In order to study the characteristics and controlling factors of the reservoirs in the Lower Cambrian Longwangmiao Formation in eastern Sichuan Basin and its adjacent areas,we analyzed the laboratory data of thin sections,cathode luminescence,scanning electron microscope and physical properties, and log data. The result shows that: (1)The main types of reservoir rocks of the Longwangmiao Formation are grain carbonate rocks,and silty-fine crystalline dolostones following. (2)The main types of reservoir space of the Longwangmiao Formation are intergranular(dissolved)pores,intercrystalline(dissolved)pores,intragranular dissolved pores,followed by structural fractures,dissolution fracture. The reservoirs have low porosity and permeability with average matrix porosity of 4.25％ and permeability of 6.25×10-3μm2; The reservoirs could be divided into two types: the porous type and the fractured-dissolution-porous type. (3)The formation and distribution of the reservoirs in the Longwangmiao Formation may be influenced by three controlling factors including sedimentation,diagenesis and burial process. Sedimentation provided the geological background for the reservoir development;diagenesis was the key factor influencing the reservoir development;and the burying process,which is one of the reasons why the reservoirs in eastern Sichuan Basin have poor quality comparing with those in central and southeastern Sichuan Basin,affected the formation of the reservoirs eventually. (4)It was concluded that the favorable reservoirs were developed mainly in the banks,and secondly in the tidal flats of the restricted platform, overall, considering the lithology, physical property, thickness and distribution range synthetically.
. Characteristics and controlling factors of the Lower Cambrian Longwangmiao Formation reservoirs in easternSichuan Basin and its adjacent areas[J]. JOPC, 2015, 17(6): 829-840.
