【摘要】：細粒巖的沉積環(huán)境研究對于頁巖油的有利區(qū)帶的預(yù)測以及勘探開發(fā)具有重要的參考價值。本文以有機質(zhì)含量豐富的東營凹陷沙四上亞段細粒巖為研究對象,通過對其巖石學(xué)特征、紋層特征、整體宏觀的沉積環(huán)境、巖相組合的控制因素進行分析,對細粒巖的沉積模式以及沉積體系進行提煉分類。在研究過程中,本文創(chuàng)新性地將米蘭科維奇旋回同細粒巖進行綜合分析,發(fā)現(xiàn)天文旋回對于細粒巖的沉積確實有著較大影響作用。其中,尤其以23ka(千年)的歲差旋回的作用最為明顯。細粒巖的物質(zhì)及其來源是細粒巖研究所要解決的基本問題。本文研究區(qū)的細粒巖的主要物質(zhì)組成為石英、碳酸鹽、粘土礦物、有機碳以及黃鐵礦。石英和粘土礦物以來自陸源為主,還有少量石英是成巖過程中形成的自生石英;碳酸鹽以生物化學(xué)成因為主,亦有少部分來自陸源;有機質(zhì)多為Ⅰ型和Ⅱ1型,來自藻類和浮游生物;黃鐵礦多為草莓狀集合體,高度自形。細粒巖的沉積構(gòu)造多為水平層理、交錯層理、塊狀層理以及透鏡狀層理等。研究區(qū)細粒巖在薄片下多以紋層形式出現(xiàn),其基本紋層為粘土紋層、碳酸鹽紋層、有機質(zhì)紋層以及混合紋層。本文針對細粒巖的紋層特征提出了渾水-半渾水-清水模式的紋層成因機制,在渾水階段多形成粘土紋層或者混合紋層,半渾水階段多形成混合紋層,清水階段多形成碳酸鹽紋層,由于這個三個階段持續(xù)時間的長短不同,從而導(dǎo)致研究區(qū)出現(xiàn)不同的紋層組合。利用研究區(qū)重點井自然伽馬測井?dāng)?shù)據(jù)進行分析后發(fā)現(xiàn),細粒巖中存在顯著的米蘭科維奇旋回,其中,23ka的歲差旋回與細粒巖的礦物成分變化具有良好的對應(yīng)關(guān)系,即天文旋回控制了細粒巖的沉積,導(dǎo)致其出現(xiàn)了不同的巖相組合。針對東營凹陷沙四上亞段細粒巖,將其劃分為4個沉積體系:1)渾水沉積體系,主要為高有機質(zhì)泥巖和中有機質(zhì)泥巖;2)半渾水沉積體系,主要為中有機質(zhì)混合細粒巖和低有機質(zhì)混合細粒巖;3)清水沉積體系,主要為中有機質(zhì)碳酸鹽巖和低有機質(zhì)碳酸鹽巖;4)濁流沉積體系,主要為條帶狀粉砂巖。
[Abstract]:The study of sedimentary environment of fine-grained rocks has important reference value for prediction of favorable zones of shale oil and exploration and development. In this paper, the fine granulites of the upper member of Sha 4 in Dongying sag with abundant organic matter are taken as the research object. The petrological characteristics, the characteristics of the grain layer, the overall macro sedimentary environment and the controlling factors of the lithofacies combination are analyzed. The sedimentary model and sedimentary system of fine-grained rocks are refined and classified. In the course of the research, the Milankovich cycle and the fine-grained rock are analyzed synthetically in this paper. It is found that the astronomical cycle does have a great influence on the deposition of the fine-grained rocks. In particular, the role of precession cycle of 23ka (millennium) is the most obvious. The material and source of fine-grained rock is the basic problem to be solved by the study of fine-grained rocks. The main material composition of the fine-grained rocks in this study area is quartz, carbonate, clay minerals, organic carbon and pyrite. Quartz and clay minerals are mainly derived from continental sources, and a small amount of quartz is authigenic quartz formed during diagenesis; carbonates are mainly of biochemical origin, and a few of them come from land-based sources; most of the organic matter are of type I and type 鈪，

本文編號：2278461