準(zhǔn)噶爾南緣構(gòu)造沉積演化及其控制下的基本油氣地質(zhì)條件

1、準(zhǔn)噶爾南緣構(gòu)造沉積演化及其控制下的基本油氣地質(zhì)條件        準(zhǔn)噶爾南緣山前帶及其鄰區(qū)作為中國(guó)中西部前陸盆地的重要組成部分,已經(jīng)成為中國(guó)西部油氣勘探的熱點(diǎn)地區(qū)和前沿領(lǐng)域。但由于大地構(gòu)造位置特殊,分別受到海西、印支、燕山和喜馬拉雅多期次不同構(gòu)造體系的復(fù)合與疊加以及同期次不同構(gòu)造體系的聯(lián)合與制約,使其最終成為一個(gè)以晚古生代、中新生代陸相沉積為主體的復(fù)合疊加盆地。特別是喜山期強(qiáng)烈構(gòu)造改造作用使研究區(qū)成為油氣勘探的復(fù)雜區(qū)。因此,對(duì)研究區(qū)的構(gòu)造演化與油氣聚集進(jìn)行深入研究,將有助于確定研究區(qū)不同階段成盆作用及改造作用的動(dòng)態(tài)

2、過程,為更好地對(duì)準(zhǔn)噶爾南緣油氣資源及勘探目標(biāo)進(jìn)行客觀評(píng)價(jià)提供充足的證據(jù)。論文以沉積盆地動(dòng)力學(xué)理論為指導(dǎo),以構(gòu)造沉積綜合分析為研究手段,以地面地質(zhì)、井下地質(zhì)、地球物理、地球化學(xué)方法和各種分析測(cè)試資料為基礎(chǔ),以成盆作用及改造作用的動(dòng)態(tài)過程為主線,深入開展了研究區(qū)及鄰區(qū)晚石炭世以來構(gòu)造特征、不同構(gòu)造旋回的盆地原型、中新生代構(gòu)造轉(zhuǎn)換關(guān)鍵時(shí)刻(或界面)的構(gòu)造變形及其三維結(jié)構(gòu)形式以及與油氣聚集關(guān)系的研究。研究區(qū)巖石地球化學(xué)與地球物理資料的綜合研究表明:準(zhǔn)噶爾盆地存在三重基底-前寒武紀(jì)古老結(jié)晶基底、晚加里東褶皺基底和華力西期的褶皺基底。晚石炭世以來的構(gòu)造特征研究表明:中二疊世末、早三疊世末、晚三疊世末、中侏

3、羅世巴柔期末、晚侏羅世末、早白堊世末和中新世末是北天山造山帶與準(zhǔn)噶爾盆地南緣構(gòu)造體制發(fā)生根本性轉(zhuǎn)變的關(guān)鍵時(shí)刻。據(jù)此將研究區(qū)構(gòu)造層劃分為:晚海西構(gòu)造層、印支構(gòu)造層、燕山構(gòu)造層和喜馬拉雅構(gòu)造層。其中準(zhǔn)噶爾南緣前陸盆地和北天山地區(qū)陸內(nèi)造山-成盆作用的構(gòu)造形成主要發(fā)生在中新生代,但以喜馬拉雅期為主。將研究區(qū)劃分為博格達(dá)山前沖斷帶、伊山山前沖斷帶、四棵樹凹陷、阜康凹陷、昌吉凹陷與三臺(tái)凸起等基本構(gòu)造單元。博格達(dá)山前沖斷帶主體為一逆沖推覆體,喜山期是該構(gòu)造帶的最終定型期;伊山山前沖斷帶可劃分為以厚皮構(gòu)造為特征的伊山前緣斷褶帶和以薄皮構(gòu)造為特征的伊山山前滑脫帶,并對(duì)其基本構(gòu)造樣式和成因機(jī)理進(jìn)行了深入討論。在古

4、硫、物源、砂巖碎屑模型、碎屑巖地球化學(xué)、碎屑巖重礦物組合等特征研究的基礎(chǔ)上,對(duì)研究區(qū)晚石炭世以來不同構(gòu)造期次的盆地原型進(jìn)行了深入研究,明確提出:晚石炭世-中二疊世盆地具陸內(nèi)裂谷盆地類型,晚二疊世-早三疊世盆地為沖斷山前坳陷盆地,中晚三疊世盆地為準(zhǔn)平原化型的坳陷盆地,早中侏羅世盆地為弱伸展構(gòu)造背景下的坳陷盆地,中晚侏羅世盆地為沖斷山前坳陷盆地,白堊紀(jì)-中新世盆地為穩(wěn)定坳陷盆地和上新世-第四紀(jì)盆地為強(qiáng)烈沖斷前陸坳陷盆地,并對(duì)不同構(gòu)造期次原始盆地的構(gòu)造沉積格局進(jìn)行了探討和恢復(fù)。通過對(duì)喜山期構(gòu)造特征與油氣聚集關(guān)系的研究,認(rèn)為研究區(qū)具備三套有利生儲(chǔ)蓋組合,即二疊系-三疊系的下部成藏組合、侏羅系-白堊系的

5、中部成藏組合和白堊系-新近系的上部成藏組合。中新生代構(gòu)造應(yīng)力晨刂葡碌囊約壇行緣募費(fèi)棺饔夢(mèng)?韉墓乖旎疃?怯跋煅芯殼?推?鈧站奐?氤剎氐墓丶?蛩亍');ReplaceFont('EnDivSummary',' As important component of foreland basin of Central-western China, piedmont structural zone of south margin of Junggar and adjacent area have became the research focus and frontier

6、field. Because of special tectonic position, superimposed and restricted respectively by structure system of multi-stages and synch-stages of Variscan period, Indosinian period, Yanshan period and Himalaya period, margin of Junggar and adjacent area finally became a composite superposition basin, ma

7、inly composed of continental deposit of late Paleozoic and Meso-Cenozoic. By the research of the relation between tectonic evolution and enrichment of hydrocarbon, it is conduced to confirm the dynamic process of basin formation action and transformation action of different stage, and provide the su

8、fficient evidence for objective evaluation of the hydrocarbon resource and exploration object optimize.Guided of the dynamics theory of sedimentary basin, approached of the structure-sedimentary research, based on the surface geology, underground geology, geophysical, geochemistry and various analyz

9、ing and testing data, mainlined on basin formation action and transformation action, structure character, basin prototype of difference cycle, the structure deformation and 3D structure form and the relation to the enrichment of hydrocarbon of the key time of Meso-Cenozoic are being studied deeply.A

10、ccording to the rock geochemistry and geophysical data, it shows that there are triple basements in Juggar basin: ancient ctystallization basement of Precambrain, folded basement of late-Caledonian and folded basement of Variscan. The structural character since late Carboniferous indicates that ther

11、e are seven critical moments of tectonic regime conversion between north Tianshan and south margin of Juggar: end of the middle Permian, end of the early Triassic, end of late Triassic, end of Bajocian stage of middle Jurassic, end of late Jurassic, end of early Cretaceous and end of Miocene. Based

12、on critical moments, tectonic sequence in the study area can be divided into four: tectonic sequence of late Variscan period, Indosinian period, Yanshan period and Himalaya period.The main formation time for foreland basin of south margin of Juggar and inner continental orogen-basin formation of nor

13、th Tianshan area is Himalaya period of Meso-Cenozoic. Tectonic units in the study area can be divided into six parts: Bogda piedmont thrust belt, Yishan piedmont thrust belt, Sikeshu depression, Fukang depression, Changji depression and Santai depression. Bogda piedmont thrust belt is an overthrust

14、nappe, formed in Himalaya period. Yishan piedmont thrust belt is subdivided into two parts: fault-fold belt of Yishan front characteristic of thick-skinned structure and decllement zone of piedmont of Yishan characteristic of thin-skinned structure. Sikeshu depression is divided into three parts: mo

15、nocline in the south, fold belt in the middle and monocline in the north. According to the basin prototype, tectonic stage can be divided into eight: continent rift vally stage from late Carboniferous to Middle Permian, thrust depression stage from early Permian to early Triassic, concentrating stag

16、e in mid-late Triassic, weak extension stage in early-middle Jurassic, thrust depression stage in mid-late Jurassic, depression stage in Cretaceous, steady depression stage from Paleocene to Miocene, the formation stage of intense overthrust belt and foreland basin form Pliocene to Quaternary.According to the relation between structure of Himalaya stage and enrichment of hydrocarbon, three sets of source reservoir cap assemblage are divided: lower assemblage from Permian to Triassic, middle assemblage from Jurassic to Cr