Sedimentary facies and sequence stratigraphy in the Lower Triassic Jialingjiang Formation, Sichuan Basin, China

Chunyan Sun,Mingyi Hu,Ngong Roger Ngia,Zhonggui Hu

doi:10.1007/s13202-018-0551-3

Chunyan Sun, Mingyi Hu + Show 2 more

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https://doi.org/10.1007/s13202-018-0551-3

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Abstract

The Lower Triassic Jialingjiang Formation is an important oil and gas exploration target in the Sichuan Basin. The lithofacies mainly consists of clastic rocks, carbonates, and evaporates, which represents a transition from continental to marine depositional environment. The Jialingjiang Formation of the Sichuan Basin is a typical epeiric carbonate platforms. The study area contains four types of facies, including mixed tidal flat facies, open platform facies, restricted platform facies, and evaporitic platform facies. Based on the analysis of cores and logging data, two types of type II sequence boundaries were identified, which are, respectively, local exposure unconformity boundary and lithology and lithofacies transformation boundary. The Jialingjiang Formation is divided into three third-order sequences and six system tracts. Thus, we establish a connected multi-well sequence stratigraphic framework based on typical single-well sequence stratigraphic division. The sedimentary evolution of the Jialingjiang Formation was divided into three major sedimentary periods and six stages, with rising and falling of the sea level, mixed tidal flat, open platform, and restricted platform prograded first, and then restricted platform and evaporitic platform retrograded. It also shows that the open platform shoal and restricted platform tidal flat have oolitic limestone and algal dolomite with good-quality physical properties and are the favorable reservoir facies belt for hydrocarbon exploration and development.

Highlights

In recent years, oil and gas exploration in the Lower Triassic marine strata in the Sichuan Basin has made a significant progress
The purpose of this study is to describe the internal sequence structure and sedimentary system of the Jialingjiang Formation in the Sichuan Basin and to predict the distribution of favorable hydrocarbon reservoirs
Many scholars have worked on sequence stratigraphic application to hydrocarbon exploration (Vail et al 1977; Thanguay and Friedman 2001). In accordance with their theories and based on the comprehensive study of seismic and logging data, we identified two types of sequence boundary, which includes unconformity boundary and the transformation boundary of lithology and lithofacies transformation boundary

Summary

Introduction

Oil and gas exploration in the Lower Triassic marine strata in the Sichuan Basin has made a significant progress. Many scholars have studied the carbonate reservoirs in different basins, and found that the carbonate rocks in the Lower Triassic of Sichuan Basin have large thickness and good-quality physical properties, and favorable. Journal of Petroleum Exploration and Production Technology (2019) 9:837–847 and spatial distribution of sedimentary facies, and explain the evolution of the Jialingjiang Formation in detail based on cores from 18 wells and 5 outcrop profiles. The purpose of this study is to describe the internal sequence structure and sedimentary system of the Jialingjiang Formation in the Sichuan Basin and to predict the distribution of favorable hydrocarbon reservoirs. The Sichuan Basin is a large Paleozoic and Meso-Cenozoic marine and continental basin within the Sichuan depression of the Yangtze paraplatform, covering an area of about 260,000 km. The structural pattern of the basin is dominated by two NE–SW and NW structural lines, forming a typical diamond-shaped basin (Fig. 1)

Objectives

Conclusion