摘 要：南美地區(qū)擁有豐富的油氣資源，是我國重點(diǎn)海外戰(zhàn)略目標(biāo)區(qū)之一，在我國海外油氣發(fā)展中占據(jù)越來越重要的地位。奧連特（Oriente）盆地位于南美次安第斯前陸盆地鏈北部，是厄瓜多爾最重要的含油氣盆地之一，已有大量地質(zhì)研究涉及該盆地的形成與構(gòu)造演化,但在磁力場特征及磁性體分布特征方面的研究卻較少。本文以奧連特盆地的航磁ΔT異常為基礎(chǔ)，應(yīng)用SUFER系統(tǒng)模擬該地區(qū)的磁場特征做了球體正演模型，應(yīng)用RIGS系統(tǒng)對數(shù)據(jù)做低磁緯度化極、正則化濾波、向上延拓、滑動平均、水平方向梯度模、垂向二階導(dǎo)數(shù)處理，通過研究，深入分析并總結(jié)了奧連特盆地的磁異常特征和磁性體分布情況，為本地區(qū)油氣資源勘探和資源評價提供參考和依據(jù)。

　　　本文在低磁緯度化極的基礎(chǔ)上，運(yùn)用垂向二階導(dǎo)數(shù)、滑動平均、正則化濾波等進(jìn)行了場的分離，得到了研究區(qū)磁異常向上延拓圖、導(dǎo)數(shù)異常圖、水平總梯度異常圖等基礎(chǔ)圖件，對研究區(qū)的磁力場進(jìn)行了分區(qū)和特征解釋，結(jié)合地質(zhì)資料對奧連特盆地的磁資料進(jìn)行綜合研究，推測出研究區(qū)斷裂構(gòu)造體系和基底的起伏特征，采用正則化濾波，圈定了局部異常，并分析了異常的基本特征。取得的結(jié)論如下：

    (1)球體模型對比分析的結(jié)果表明，異常采用低磁緯度化極后得到的正異常的規(guī)模和水平面投影位置恰能反應(yīng)異常的基本形狀和投影位置。

　　　(2)研究區(qū)內(nèi)北部異常相對較弱且在地質(zhì)圖上地表沒有古老地層出露，異常位置與剖面圖中基底隆起位置基本一致，推測異常是由基底隆起所致。

　　　(3)研究區(qū)內(nèi)西南部區(qū)域高異常在剖面圖上其走向與逆沖推覆構(gòu)造走向基本一致，推測異常是由逆沖構(gòu)造引起，也可能是蓋層中侵入巖引起。

　　　(4)研究區(qū)內(nèi)東部幅度高且范圍大，強(qiáng)磁異常的走向與圖中基底的深大斷裂走向一致推測該異常是由其引起。

　　　

關(guān)鍵詞：厄瓜多爾；奧連特盆地；航磁ΔT異常；低磁緯度化極；磁性體分布 

Magnetic Field Characteristics and The Distribution of Magnetic Body at Oriente Basin in Ecuador

Abstract：There are abundant oil-gas resources in South America, it is also the focus of overseas strategic target in our country and becoming more and more important in overseas oil-gas resource development. Orient Basin is located in the northern of sub-Andean foreland basin chain in South America, it is one of he most important oil-gas basins in Ecuador. there is a large number of geological studies about the formation of the basin and tectonic evolution. However, there are few studies relate to magnetic field characteristics and distribution of the magnetic body. In this paper, the study is based on aeromagnetic ΔT anomaly, We apply the Surfer system to Simulate magnetic field characteristics in the region to make some ball forward modeling. By applying the RIGS system processing the aeromagnetic data of Oriente in different ways, such as: canonical filtering, upward continuation, moving average, Horizontal gradient mode, Vertical second derivative processing. Through the research, we analyzed and summarized the characteristics of magnetic anomalies and the distribution of the magnetic body in Oriente basin, intending to provide reference and basis for the exploration of oil-gas in this area and resource assessment.

　　  We based on the magnetic polarization of low magnetic latitude making some processing, such as: canonical filtering, upward continuation, moving average, Horizontal gradient mode, Vertical second derivative processing, acquired the upward and downward continuation maps, derivative anomaly maps and horizontal total gradient maps. The gravity and magnetic anomaly are described and interpreted. Comprehensive study of gravity and magnetic data is discussed combined with geological data on the basin. Then deduced the fault structure system and The ups and downs of the basement feature in the study area. According the canonical filtering to obtained the delineation of the local anomaly. The main results and conclusions obtained are as follows:

　　  (1)The Analysis of sphere model shows that, after the magnetic polarization of low magnetic latitude the scale of the positive anomaly and the Horizontal projection location indicate the location and radius of the sphere model .

　　  (2)the anomaly in north area of the study region is Relatively weak and also have no old formation crop out in earth's surface. the position of the anomaly is basically same with the basement uplift in profile, so we infer that the anomaly is caused by it.

　　  (3)The trend of the high anomaly in south west area of the study region is basically same with the thrust fault, so we infer that the anomaly is caused by it.

　　  (4)the anomaly in east area of the study region shows a highest Amplitude and a biggest distribution, it’s trend is basically same with the discordogenic fault in basement. so we infer that the anomaly is caused by it.

Key words: Ecuador; Oriente basin; aeromagnetic ΔT abnormally; magnetic polarization of low magnetic latitude; distribution of magnetic body

目  錄

1  緒言 1

1.1  選題背景、意義及課題來源 1

1.2  研究內(nèi)容及技術(shù)線路 1

1.3  完成的工作量及主要成果 2

1.3.1  資料的收集及整理 2

1.3.2  地質(zhì)-地球物理資料的收集和預(yù)處理 2

1.3.3  航磁資料的處理解釋 2

1.3.4  取得的主要成果 2

2  研究區(qū)概況 4

2.1  自然地理概況 4

2.2  國內(nèi)外研究現(xiàn)狀 4

2.3  地質(zhì)背景 5

3  航磁資料處理解釋方法技術(shù) 10

3.1  航磁資料情況 10

3.2  資料處理解釋流程 10

3.3  主要解釋方法原理 10

3.3.1  ΔT異?；瘶O原理 11

3.3.2  低磁緯度化極 11

3.4  資料處理方法技術(shù) 12

3.4.1  資料預(yù)處理 12

3.4.2  航磁資料的處理 13

4  球體正演模型分析對比 15

4.1  相同半徑不同埋深球體模型對比 15

4.2  相同埋深不同半徑球體模型對比 17

4.3  不同半徑球體在相同深度不同接觸關(guān)系模型對比 19

4.4  對比分析結(jié)論 21

5  磁力場特征 22

5.1  區(qū)域磁力場特征 22

5.2  局部異常特征及磁性體分布 26

6  結(jié)論 29

參考文獻(xiàn) 31

附錄A 32