精度古地貌恢复技术及应用——以辽西凸起南段东营组二段下段为例

摘要/Abstract

摘要：

辽西凸起南段东营组二段下段发育大型岩性-超覆圈闭,储层发育程度以及分布范围是本区油气富集的主控因素。以油组为单位在低勘探程度区开展高精度古地貌恢复,通过剥蚀量恢复,结合埋深和地震响应特征对原始地层厚度进行了压实恢复,并运用岩性、沉积相以及地震响应特征等对该地区进行古水深校正。通过对研究区沟谷的横截面积及延伸长度定量分析,下切沟谷沿地貌形态和地形坡度由高至低,依次发育V型、U型、W型,其发育横截面积和输砂能力依次降低,且不同时期沟谷形态和发育位置的迁移控制了沉积体系发育特征。精细刻画了不同时期储层分布和沉积体系演化特征。

关键词: 辽西凸起, 古地貌, 沟谷, 沉积体系

Abstract:

Large scale of lithological-overlap traps are developed in the second member of Dongying Formation in the south of Liaoxi uplift. Development degree and distribution of reservoir are the major factors controlling oil and gas accumulation in the study area. In areas of low exploration prospects, high-precision restoration of ancient landform is utilized in each oil group units. Based on restoration of denudation, burial depth and seismic respondence features, primary strata thickness is restored. Paleo-water depth is recovered via lithology, sedimentary facies and seismic reflection. Through quantitative analysis of cross-section area and extending length of valleys, ancient landform of three kinds of incised valleys are recognized. The gradient of ancient landform, cross-section area and sand transporting capacity are reduced from V-shape, U-shape to W-shape incised valley respectively. Shapes and locations of valleys in different periods control development of sedimentary systems. We elaborately depict reservoir distribution and sedimentary evolution features in different periods.

Key words: Liaoxi uplift, ancient landform, valley, sedimentary system

中图分类号:

TE122.2

王晨杰, 黄晓波, 郭涛, 谢京, 郭瑞, 姚城. 精度古地貌恢复技术及应用——以辽西凸起南段东营组二段下段为例[J]. 现代地质, 2017, 31(06): 1214-1221.

WANG Chenjie, HUANG Xiaobo, GUO Tao, XIE Jing, GUO Rui, YAO Cheng. High Precision Paleotopography Restoration Technology and Its Application:Taking the Second Member of Dongying Strata in the South of Liaoxi Uplift as an Example[J]. Geoscience, 2017, 31(06): 1214-1221.

图/表 13

图1 辽西凸起南段构造位置图

Fig.1 Location of the south of Liaoxi uplift

图2 辽西凸起南段层序地层剖面图(位置见图1)

Fig.2 Cross section of the south of Liaoxi uplift(Location in Fig.1)

图3 地层趋势延伸法示意图

Fig.3 Restoration of eroded strata thickness via trend analysis

图4 砂岩、粉砂岩、泥岩孔隙度-深度关系曲线图

Fig.4 Variation of porosities of sandstone, siltstone and mudstone versus depth

表1 辽西凸起南段单井地层压实数据

Table 1 Compaction data in the south of Liaoxi uplift

油组	LD10-1-A2				LD10-2-A1				LD16-1-A1
油组	恢复厚度/m	现今厚度/m	压实率		恢复厚度/m	现今厚度/m	压实率		恢复厚度/m	现今厚度/m	压实率
零	111.88	66.02	0.411 7	53.11		29.23	0.453 6	76.78		45.06	0.415 2
Ⅰ	211.89	129.35	0.390 2	84.28		54.45	0.359 0	293.77		179.32	0.390 2
Ⅱ	161.27	92.25	0.428 5	183.07		125.21	0.315 1	140.72		90.19	0.359 0
Ⅲ	75.08	42.38	0.441 3	249.94		155.12	0.378 9	215.32		126.22	0.415 2
Ⅳ	118.47	65.12	0.450 5	114.57		68.15	0.404 8	65.11		38.16	0.414 9

图5 Ⅱ油组剥蚀地层厚度、原始地层厚度和古水深恢复图 (a)Ⅱ油组未剥蚀地层厚度图;(b)Ⅱ油组原始地层厚度图;(c)Ⅱ油组古水深恢复图

Fig.5 Thickness of eroded layers, initial thickness and paleo-water depths recovered of the second oil group

图6 LD10-2-A1井沉积构造特征

Fig.6 Sedimentary characteristics of LD10-2-A1

表2 辽西凸起南段单井古水深数据

Table 2 Paleo-water depth data in the south of Liaoxi uplift

油组	LD10-1-A2
油组	水深+恢复厚度/m	水深/m	恢复厚度/m
零	114.88	3	111.88
Ⅰ	213.89	2	211.89
Ⅱ	166.27	5	161.27
Ⅲ	79.08	4	75.08
Ⅳ	120.47	2	118.47
油组	LD10-2-A1
油组	水深+恢复厚度/m	水深/m	恢复厚度/m
零	58.11	5	53.11
Ⅰ	88.28	4	84.28
Ⅱ	188.07	5	183.07
Ⅲ	253.94	4	249.94
Ⅳ	117.57	3	114.57
油组	LD16-1-A1
油组	水深+恢复厚度/m	水深/m	恢复厚度/m
零	83.78	7	76.78
Ⅰ	302.77	9	293.77
Ⅱ	150.72	10	140.72
Ⅲ	223.32	8	215.32
Ⅳ	71.11	6	65.11

图7 辽西凸起南段东营组二段下段古地貌演化图

Fig.7 Ancient landform evolution of LD16-1-A1 the second member of Dongying Formation in the south of Liaoxi uplift

图8 沟谷发育类型

Fig.8 Development types of valleys

表3 沟谷横截面积和延伸长度分布数据

Table 3 Cross-sectional areas and lengths of valleys

沟谷类型	最大横截面积/m²	最小横截面积/m²	平均横截面积/m²
V	155 216	41 884	87 623
U	70 324	52 305	63 751
W	71 061	46 540	57 023
沟谷类型	最大延伸长度/m	最小延伸长度/m	平均延伸长度/m
V	4 186	1 456	2 470
U	2 890	851	2 039
W	1 486	1 050	1 198

图9 沟谷横截面积和延伸长度分布图

Fig.9 Cross-plotting of cross-section areas and lengths from valleys

图10 沟谷分布图及其地震,沉积反射特征

Fig.10 Valley distribution, seismic characteristics and sedimentary facies of the study area

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