普光气田与建南气田长兴组、飞仙关组储层对比研究

A COMPARATIVE STUDY OF RESERVOIRS OF THE CHANGXING AND FEIXIANGUAN FORMATION BETWEEN PUGUANG GASFIELD AND JIANNAN GASFIELD IN THE SICHUAN BASIN

管宏林 蒋小琼 王恕一 鲍云杰

Guan Honglin Jiang Xiaoqiong Wang Shuyi Bao Yunjie

中国石油化工股份有限公司, 石油勘探开发研究院, 无锡石油地质研究所, 江苏, 无锡, 214151 2. 中国地质大学, 地球科学学院, 武汉, 430074

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214151 China 2. Faculty of Earth Sciences, China University of Geosciences, Wuhan, Hubei 430074, China

普光气田和建南气田位于四川盆地东北部,两气田的主力产层二叠系长兴组、三叠系飞仙关组均为礁滩沉积,但储层规模、储集性却差异很大。普光气田储层厚度大、物性好,以中孔中渗、高孔高渗的大套溶孔白云岩为主,而建南气田储层厚度小、物性差,以低孔低渗为主,岩性为灰岩和少量白云岩。研究认为,白云岩成因的差异造成了2个气田储层的差异。普光气田以准同生白云岩化为主,形成了大量早期白云岩;建南气田以埋藏白云岩化为主,形成的白云岩数量少。白云岩成因的差异与沉积环境密切相关,普光气田礁滩沉积毗邻局限台地或蒸发台地,容易获得高Mg/Ca比咸水,有利于准同生白云岩化发育;而建南气田礁滩沉积毗邻开阔台地,不利于准同生白云岩化的发育。因此,毗邻蒸发台地或局限台地等环境的礁滩相更有利于优质储层的发育。

Puguang Gasfield and Jiannan Gasfield are located in Northeast Sichuan Basin.As the main gas bearing zones,the Permian Changxing and Triassic Feixianguan Formations are all reef-bank deposits.However,the reservoir scale and property are greatly different between Puguang Gasfield and Jiannan Gasfield.The reservoirs in Puguang Gasfield are mainly a large set of dolomites with the characteristics of dissolution pores,great thickness,medium porosity and medium permeability,high porosity and high permeability.However,the reservoirs in Jiannan Gasfield are mainly limestones and a little dolomites with the characteristics of thin thickness,low porosity and low permeability.Based on the comparative study on the formation conditions,the primary factor for differences towards the reservoirs between Puguang Gasfield and Jiannan Gasfield is the origin of the dolomites.The former well developed penecontemporaneous dolomitization and formed a large set of dolomites while the latter developed burial dolomitization and formed a little dolomites.Correlation analysis results showed that there is a close correlation to the differences of the sedimentary environment.The reef-bank facies are adjacent to the restricted platform facies or evaporate platform facies in Puguang Gasfield,however,which are adjacent to the open platform facies in Jiannan Gasfield.As a result,the former is easier to acquire saline water of high Mg/Ca values and beneficial to penecontemporaneous dolomitization while the latter is not avail to penecontemporaneous dolomitization.Consequently,it is suggested that the reef-bank facies adjacent to the sedimentary environment such as restricted platform facies or evaporate platform facies are advantageous to forming quality reservoirs.

中国石油化工股份有限公司油田开发部项目(YTB2006-01)

https://doi.org/10.11781/sysydz201002130