摘要
预测四川盆地覆盖区的中下寒武统优质膏质岩盖层的分布,为油气勘探提供依据。通过石膏露头细测、野外剖面实测与钻录井分析的方法,发现四川盆地南部的雷波县沙坪子西王庙组(-C2x)、火草坪龙王庙组(-C1l)2个中下寒武统石膏露头点,膏质岩层出露6层,厚度>21.5m。描述了甘洛县黑马中寒武统大鼻山组(-C2d)石膏露头共5层,厚度>18.5m。同时,窝深1井也揭示中下寒武统膏质岩层,在抓抓岩与乐山范店实测剖面上发现了可与石膏露头、钻井类比的膏溶角砾岩。研究表明,雷波-甘洛石膏露头区发育内缓坡相、蒸发岩台地(或塞卜哈)、局限台地相潮间坪亚相与潟湖亚相的石膏岩与膏溶角砾岩沉积,它们与泥晶白云岩或红色泥岩共生;蒸发岩台地堆积紫红色泥质岩与透镜状、结核状、角砾状构造的灰色泥晶含石膏质白云岩;局限台地相发育潮间坪亚相韵律条带、波状构造的石膏质白云岩、含白云质石膏岩与膏溶角砾岩,以及盐湖或潟湖亚相块状纯石膏岩与韵律条带构造的含白云质石膏岩。这些膏质岩的确认与相分析表明四川盆地南部发育一条长60～70km膏质岩带,它对油气勘探具有重要的意义。
To predicting the distribution of the Middle-Lower Cambrian high-quality gypseous rocks seals in Sichuan Basin aims at providing the evidence for oil and gas prospecting. Based on the measurement of the outcrop profiles, fine description of gypsolith outcrops, and examination of cores, two gypsolith outcrops with 6 layers and ）21.5 m thick and 6 layers, are discovered from the Middle Cambrian Xiwangmiao Formation of Shapingzi and the Lower Cambrian Longwangmiao Formation of Hochaoping of Leibo County in the south of Sichuan Basin. The paper describes the gypsolith outcrops with 5 layers and ）18.5 m thick from the Middle Cambrian Dabishan Formation in Heima of Ganluo County in the south of Sichuan Basin. At the same time, the gypsolith and the dissolved gypseous breccia on the earth surface outcrops are compared with those of the Middle-Lower Cambrian from Well Wosheng 1. On the Zhuazhuayan and Fandian surveying profiles of Cambrian, the authors also find the dissolved gypseous breccia and compare them with those of the outcrops and wells. It is concluded that the gypsolith and the dissolved gypseous breccia have deposited in the inner ramp platform, evaporite platform, and inter tide-flat subfacies of restricted platform in the Leibo-Ganluo zone. They are interbedded with micrite dolostone or red mudstone and covered by the red mudstones on the top. The amaranth mudstone and gray mierite gypsum-bearing dolostone with lenticular, nodular and brecciform sedimentary structures on the rocks have deposited in the evaporite platform or sabkha, while the inter-tide flat subfacies of gypseous dolostone, dolomite-bearing gypsolith and the dissolved gypseous breccia, and salt lake or lagoon subfacies massive pure gypsolith and rhythmically banded dolomite-bearing gypsolith have grown in the restricted platform. The confirmation of the gypseous rocks and facies analysis suggests that there is a gypsolith zone with 60-70 km length. It is of great significance for the oil and gas prospecting.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2012年第1期63-69,共7页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家自然科学基金资助项目(40739904)
中国石化重大科技攻关项目(P0105)
关键词
石膏露头
蒸发台地相
中下寒武统
油气勘探
四川盆地
gypsolith outcrop
evaporative platform
Cambrian
oil and gas prospecting
Sichuan Basin
