Low-amplitude Structures and Its Control on Hydrocarbon Enrichment and Accumulation: An Example from Yan’an Formation in Pengyang Area, Ordos Basin

doi:10.19657/j.geoscience.1000-8527.2021.042

Abstract

Abstract:

Low-amplitude structures are widely developed at Pengyang. As Pengyang is distal from the source rock, the oil had undergone long-distance vertical and lateral migration, and the relations between structures and oil accumulation is unclear. Considering the geological and tectonic characteristics and based on sizable drilling and production data, we studied the low-amplitude structures of Yan 9 oil layer at Pengyang and its controlling effect on hydrocarbon enrichment and accumulation. The results show that low-amplitude structures at Pengyang are widely developed, dominated by nose-like structures. Low-amplitude structures with >18 m structural amplitude and >2.8 km² closed area likely caused effective oil-water heterogeneity, and provided desirable traps for hydrocarbon accumulation. Accumulation of the study area is controlled by paleogeomorphology and can be divided into two types, i.e.slope mouth and fluvial ancient highland slope accumulation. The low-amplitude structures located in the dominant paleogeomorphology accumulation area could facilitate large-scale accumulation, and comprise 10 structural units. As they are in different locations and restricted by different accumulation factors, their hydrocarbon accumulation controlling factors are different. The (1) to (5) structural units in the north are located near the hydrocarbon generation center in the Jurassic paleogeomorphology-dominant accumulation area, with the oil enrichment mainly controlled by the structures. The degree of oil enrichment increases with increasing structural amplitude and closed area. The (6) to (10) structural units in the southwest are not in the Jurassic paleogeomorphology-dominant accumulation area, and low-amplitude structures are necessary for hydrocarbon accumulation (rather than being a main controlling factor). There is no clear correlation between the scale of low-amplitude structures and the degree of oil enrichment.

Key words: Pengyang area, Yan 9 oil layer, low-amplitude structure, structural units, oil enrichment and accumulation, controlling effect

CLC Number:

TE122.1

ZHENG Dengyan, WANG Zhenliang, WANG Lianguo, HUANG Hao. Low-amplitude Structures and Its Control on Hydrocarbon Enrichment and Accumulation: An Example from Yan’an Formation in Pengyang Area, Ordos Basin[J]. Geoscience, 2021, 35(04): 1114-1123.

Figures/Tables 12

Fig.1 Location map of the study area

Fig.2 Integrated sedimentary stratigraphic diagram of Yan 9 oil layer at Pengyang (with well Yan 116 as an example)

Fig.3 Structural map of Yan 9 oil layer at Pengyang

Table 1 Characteristics of structural assemblages in Yan 9 oil layer at Pengyang

构造组合	隆起幅度范围/m	隆起幅度平均值/m	闭合面积范围/km²	闭合面积平均值/km²	主要工业油流井	最高产量 (吨/天)
(1)	10~32	22.81	3.02~54.32	20.07	演135,演1-16,演147, 镇178,镇190,演157	31.88
(2)	15~35	17.50	3.36~9.68	7.60	镇516,木64	20.74
(3)	15~35	22.29	2.18~42.29	12.43	镇187	4.42
(4)	25~36	30.00	10.65~26.44	17.66	演239,演13	40.72
(5)	35~39	36.00	9.05~11.69	9.71	镇353,镇250	34.9
(6)	25~55	30.00	3.9~17.55	7.59	/	/
(7)	10~29	19.80	2.39~14.48	7.93	演43	31.03
(8)	15~20	17.00	6.18~12.63	9.51	木153	20.09
(9)	30	30.00	62.21	62.21	演224	35.68
(10)	22~25	23.50	28.05~46.01	37.03	/	/

Fig.4 Burial history map of well Yan22 at Pengyang (after ref. [15])

Fig.5 Anticlinal structural reservoir profile (with well Yan 224 as an example)

Fig. 6 Oil cluster accumulation of low-amplitude structures (modified from ref. [2])

Fig.7 Initial oil saturation plan of Yan 9 oil layer at Pengyang

Fig.8 Relations between low-amplitude structures and oil production at Pengyang

Fig.9 Paleogeomorphologic map of the Pengyang area

Fig.10 Relations between low-amplitude structures and initial oil saturation of the (1) to (5) structural units

Fig.11 Relations between low-amplitude structures and initial oil saturation of the (6) to (10) structural units

References 27

[1]	王建民, 张三, 杜伟, 等. 低幅度构造对特低渗透油藏油气水富集及开发动态的控制效应[J]. 石油勘探与开发, 2019, 46(4):728-738.
[2]	王建民, 王佳媛. 鄂尔多斯盆地伊陕斜坡上的低幅度构造与油气富集[J]. 石油勘探与开发, 2013, 40(1):49-57.
[3]	兰朝利, 王建国, 周晓峰, 等. 鄂尔多斯盆地彭阳油田侏罗系延安组油藏成藏规律[J]. 油气地质与采收率, 2014, 21(5):45-48.
[4]	郑忠文, 刘建朝, 李荣西. 微构造对低渗透油气成藏的控制作用——以鄂尔多斯盆地丰富川油田西区为例[J]. 西北地质, 2015, 48(4):234-242.
[5]	许艳争, 杜箫笙, 毕明柱, 等. 低幅度构造油藏富集主控因素及成藏模式——以红河油田延安组油藏为例[J]. 断块油气田, 2015, 22(5):556-560.
[6]	柴童. 彭阳地区延安组低幅度构造特征与油气成藏关系研究[D]. 西安:西安石油大学, 2018.
[7]	李相博, 姚泾利, 刘化清, 等. 鄂尔多斯盆地中生界低幅度隆起构造成因类型及其对油气分布的控制作用[J]. 现代地质, 2013, 27(4):755-764.
[8]	刘联群, 刘建平, 李勇, 等. 鄂尔多斯盆地彭阳地区侏罗系延安组油气成藏主控因素分析[J]. 地球科学与环境学报, 2010, 32(3):263-267.
[9]	白金莉, 李文厚, 刘江斌, 等. 鄂尔多斯盆地彭阳-泾川地区长8₁小层沉积储层特征[J]. 西北大学学报(自然科学版), 2020, 50(2):175-182.
[10]	王学军, 王志欣, 陈杰, 等. 鄂尔多斯盆地镇北油田延长组低渗透储层成因及油气运移特征[J]. 油气地质与采收率, 2010, 17(1):15-18.
[11]	席胜利, 刘新社, 王涛. 鄂尔多斯盆地中生界石油运移特征分析[J]. 石油实验地质, 2004, 26(3):229-235.
[12]	宋兴沛, 刘洛夫, 徐正建, 等. 鄂尔多斯盆地中西部长7段烃源岩及致密油潜力评价[J]. 新疆石油地质, 2017, 38(5):553-558.
[13]	王龙, 陈培元, 孙福亭, 等. 鄂尔多斯盆地彭阳地区延长组、延安组原油地球化学特征与油源对比[J]. 海洋地质前沿, 2019, 35(12):49-54.
[14]	于雷, 陈建文, 金文辉, 等. 鄂尔多斯盆地彭阳油田侏罗系油气富集规律研究[J]. 岩性油气藏, 2013, 25(4):33-37.
[15]	叶博, 梁晓伟, 宋娟, 等. 鄂尔多斯盆地演武地区侏罗系延安组油藏成藏特征[J]. 岩性油气藏, 2018, 30(4):65-73.
[16]	王怡. 鄂尔多斯盆地演武西地区侏罗系延安组延9-延6成藏特征及主控因素分析[D]. 成都:西南石油大学, 2017.
[17]	马晓军, 梁积伟, 李建星, 等. 鄂尔多斯盆地中西部中新生代构造抬升及演化[J]. 西北地质, 2019, 52(4):127-136.
[18]	冯娟萍, 李文厚, 欧阳征健. 鄂尔多斯地区中新元古代构造沉积演化研究[J]. 西北大学学报(自然科学版), 2020, 50(4):634-643.
[19]	刘池洋, 赵红格, 桂小军, 等. 鄂尔多斯盆地演化-改造的时空坐标及其成藏(矿)响应[J]. 地质学报, 2006, 80(5):617-638.
[20]	任战利, 张盛, 高胜利, 等. 鄂尔多斯盆地构造热演化史及其成藏成矿意义[J]. 中国科学D辑:地球科学, 2007, 37(S1):23-32.
[21]	朱静, 李文厚, 韩永林, 等. 陇东地区前侏罗纪古地貌及油藏成藏规律研究[J]. 沉积学报, 2010, 28(6):1229-1237.
[22]	王霞, 刘凤林, 范柏江, 等. 鄂尔多斯盆地吴起曾岔地区前侏罗纪古地貌与油藏成藏规律[J]. 兰州大学学报(自然科学版), 2020, 56(1):8-15.
[23]	王国壮, 梁承春, 聂小创, 等. 镇泾地区侏罗纪古地貌与延安组成藏关系[J]. 特种油气藏, 2016, 23(4):46-50.
[24]	汪海燕, 李仲东, 丁晓琪, 等. 镇泾油田侏罗纪沉积前古地貌特征与延9段油藏分布[J]. 石油天然气学报, 2008, 30(1):170-173.
[25]	马立元, 邱桂强, 李超, 等. 鄂尔多斯盆地镇泾地区延长组异常压力演化及其成藏意义[J]. 地质通报, 2020, 39(4):503-511.
[26]	姚泾利, 徐丽, 邢蓝田, 等. 鄂尔多斯盆地延长组长7和长8油层组流体过剩压力特征与油气运移研究[J]. 天然气地球科学, 2015, 26(12):2219-2226.
[27]	李超. 镇泾地区延长组致密砂岩油成藏动力演化过程研究[D]. 青岛:中国石油大学(华东), 2015.