四川盆地北部宁强胡家坝灯影组四段岩石特征及沉积环境分析

Rock features and sedimentary environment of the fourth member of Dengying Formation in Hujiaba section of Ningqiang, northern Sichuan Basin

郭旭升 胡东风 段金宝 吴浩 李毕松

GUO Xusheng HU Dongfeng DUAN Jinbao WU Hao LI Bisong

中国石化 勘探分公司, 成都 610041

Exploration Company, SINOPEC, Chengdu, Sichuan 610041, China

川中地区围绕灯影组天然气勘探取得重要进展，但川北地区勘探程度相对较低，钻井资料匮乏，针对性开展野外地质剖面岩石学特征和沉积环境解剖分析，对于该区油气勘探具有重要意义。通过对川北宁强胡家坝灯影组剖面实测与系统取样分析，运用沉积学、岩石学等方法，进行层序地层划分、岩石分类和沉积环境分析。研究表明：（1）根据岩石类型、藻类含量、泥质含量等将胡家坝灯四段划分为上下2个亚段，其中上亚段为丘滩体及储层发育的主要部位；（2）剖面灯影组四段碳酸盐岩岩石类型可划分为晶粒云岩、藻云岩和颗粒云岩3个亚类和8个微类；（3）剖面灯四段总体属于台地边缘相沉积，可划分出藻丘、颗粒滩、台坪和滩间海4个亚相；（4）灯四段沉积时期海平面表现为海进、海退2个旋回过程，沉积岩石的类型受沉积旋回海平面升降控制，整体表现为台坪、滩间海、台缘丘滩、滩间海、台缘丘滩的一个沉积演化过程。

In the central Sichuan Basin, significant progress has been made in the exploration of natural gas around the Dengying Formation. However, the exploration in the northern Sichuan Basin is relatively low and the drilling data is scarce. The petrological characteristics of the field geological section and the analysis of the sedimentary environment are of great significance for oil and gas exploration. Based on the survey and systematic sampling analysis of the Dengying Formation, Hujiaba section, sedimentary stratigraphy, rock classification and sedimentary environment analyses were carried out using sedimentology and petrology. Our research showed that:(1) According to the rock types, algae content and shale content, the 4th member of Dengying Formation, Hujiaba section can be divided into upper and lower sub-sections, of which the upper sub-section is the main part of the bioherm-beach and reservoir development; (2) The carbonate rock types of the 4th member of Dengying Formation can be divided into three sub-classes of crystalline dolomite, algae dolomite and granular dolomite, and eight micro-classes; (3) The 4th member of Dengying Formation, Hujiaba section is generally deposited on the edge of the platform, which can be divided into four subfacies of table, interbank sea, algal mound and grain beach. (4) During the deposition period of the fourth member of Dengying Formation, the sea level is characterized by two cycles of transgression and regression. The types of sedimentary rocks are controlled by the sedimentary cycle and sea level which shows a sedimentary evolution process of table facies→interbank sea facies→bioherm-beach facies→interbank sea facies→bioherm-beach facies.

国家科技重大专项“大型油气田及煤层气开发”项目“南方海相碳酸盐岩大中型油气田分布规律及勘探评价”（2017ZX05005-003）资助。

https://doi.org/10.11781/sysydz201806749