Origin of Salt Minerals and Oil-gas Geological Significance of $\mathbf{E}_{3}{ }^{2}$ Reservoirs in Saline Lacustrine Basin of the Yingxi Area, Qaidam Basin

Abstract

Abstract:

In recent years, an important discovery in exploration has been made in $\mathbf{E}_{3}{ }^{2}$ of Oligocene in Yingxi area of Western Qaidam Basin. Based on core observation, systemic microscopic characteristics analysis, mineralogy analysis and geochemical analysis, the salt minerals characteristics, origin and role in the process of hydrocarbon accumulation in Oligocene in saline lacustrine basin are systematically studied in the Yingxi area of Qaidam Basin。 (1)In this area, there are 4 important salt minerals, halite, gypsum, glauberite and celestite, which are gathered to form saline layers with certain thickness, or developed in matrix carbonate rock in the form of mineral particles. In upper reservoir group in middle of saline layers, the saline layers are thicker, and mainly rock salt, where thin oil layers are developed. In lower reservoir groups, the saline layers are thinner, and mainly gypsum. (2)Salt minerals has geochemical characteristics of ‘low content of Mn’, the matrix carbonate rock associated with salt minerals has ‘low temperature’ C-O isotope geochemical characteristics, petrological characteristics without the hydrothermal minerals and distribution characteristics of a very wide range. All of the above characteristics show the salt minerals in this area are typical deposition type in saline lacustrine basin, not hydrothermal brine precipitation type. (3)‘salt’ plays an important role in the process of hydrocarbon accumulation. Salt minerals play roles of filling crack and roles in sealing of preventing dissipation of oil and gas. Salt layers play a role in sealing and covering due to high capillary breakthrough pressure and plastic characteristics. Salt minerals promote the secondary pore development in dolomite and negative effect is occupying certain reservoir space. So the results of this research can provide an important guidance for oil and gas exploration in subsalt layer of saline lacustrine carbonate rocks.

Key words: Qaidam Basin, Yingxi area, saline lacustrine basin, $\mathbf{E}_{3}{ }^{2}$, salt mineral, role of sealing andcovering

CLC Number:

P588
TE122.1

HUANG Chenggang, LI Zhiyong, NI Xianglong, MA Xinming, ZHANG Shiming, GAO Yanfang, YANG Sen, CUI Jun, WU Kunyu. Origin of Salt Minerals and Oil-gas Geological Significance of $\mathbf{E}_{3}{ }^{2}$ Reservoirs in Saline Lacustrine Basin of the Yingxi Area, Qaidam Basin[J]. Geoscience, 2017, 31(04): 779-790.

Figures/Tables 7

Fig.1 Sedimentary facies of E 3 2 reservoir of Oligocene in Yingxi area, Qaidam Basin

Fig.2 Comprehensive column of lithology in E 3 2 reservoir of Oligocene in the Yingxi area

Fig.3 Core photographs, microscopic features and EDS spectrum of salt layer&salt minerals of Oligocene in the Yingxi area

Table 1 Statistics of the whole rock mineral content analysis by XRD of main reservoir of Oligocene in the Yingxi area

井号	样品编号	岩性描述	层位	深度 /m	石英	钾长石	斜长石	方解石	白云石	铁白云石	文石	菱铁矿	菱镁矿	石盐	黄铁矿	赤铁矿	硬石膏	钙芒硝	黏土矿物
S38	S38-1	深灰色含粉砂泥质白云岩	$E 3 2$ 盐间	2 794.62	14.8	0.9	6.5	8.4	16.2	17.5	0.0	0.0	0.0	0.6	2.4	0	4.1	2.8	25.8
S38	S38-3	深灰色泥质碳酸盐岩	$E 3 2$ 盐间	2 796.92	10.7	1.1	7.1	12.3	9.8	9.4	0.0	17.2	0.0	0.7	1.6	0	2.8	1.2	26.1
S38	S38-4	深灰色含粉砂碳酸盐岩	$E 3 2$ 盐间	2 800.72	11.4	1.2	8.4	28.2	0.0	18.8	0.0	6.7	0.0	0.5	2.5	0	3.7	1.1	17.5
S38	S38-5	灰色含泥粉砂质灰岩	$E 3 2$ 盐间	3 145.86	11.7	1.1	11.9	35.0	3.3	0.0	0.0	11.5	0.0	0.5	2.8	0	3.5	3.8	14.9
S38	S38-6	灰色含粉砂碳酸盐岩	$E 3 2$ 盐间	3 146.36	13.5	1.3	8.1	7.7	0.0	31.6	0.0	0.0	0.0	5.9	8.3	0	1.1	6.9	15.7
S37	S37-12	灰色含粉砂泥质碳酸盐岩	$E 3 2$ 盐间	2 692.02	12.6	1.1	8.9	25.0	0.0	17.8	0.0	0.0	0.0	1.1	2.7	0	0.9	1.8	28.2
S37	S37-13	灰色含云膏质粉砂岩	$E 3 2$ 盐间	2 697.07	22.9	1.5	11.3	2.7	0.0	14.9	0.0	5.4	0.0	1.3	1.7	0	7.8	19.3	11.4
S37	S37-14	石盐	$E 3 2$ 盐间	2 695.25	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	100.0	0.0	0	0.0	0.0	0.0
S1-2	S1-2-1	含灰白云岩	$E 3 2$ 盐间	2 757.70	10.7	1.1	7.6	17.2	0.0	50.0	0.0	0.0	0.0	0.4	2.9	0	0.6	0.0	9.6
S1-2	S1-2-2	含粉砂碳酸盐岩	$E 3 2$ 盐间	2 757.78	13.1	0.4	9.6	21.9	0.0	30.4	0.0	0.0	0.0	0.8	4.5	0	0.7	0.0	18.6
S1-2	S1-2-5	灰质白云岩	$E 3 2$ 盐间	2 758.10	9.8	0.4	6.2	25.5	0.0	42.7	0.0	0.0	0.0	1.2	0.0	3.5	0.4	0.0	10.4
S1-2	S1-2-7	灰质白云岩	$E 3 2$ 盐间	2 758.10	9.8	0.4	6.2	25.5	0.0	42.7	0.0	0.0	0.0	1.2	0.0	3.5	0.4	0.0	10.4
S1-2	S1-2-8	含粉砂白云岩	$E 3 2$ 盐间	2 758.19	11.3	0.4	5.5	13.3	0.0	52.8	0.0	0.0	0.0	0.9	5.7	0.0	0.3	0.0	9.8
S1-2	S1-2-9	粉砂质白云岩	$E 3 2$ 盐间	2 758.33	16.8	0.8	10.1	13.4	0.0	43.1	0.0	0.0	0.0	0.6	3.0	0.0	0.4	0.0	11.7
S1-2	S1-2-10	含粉砂白云岩	$E 3 2$ 盐间	2 758.39	11.6	0.4	5.6	13.5	0.0	52.6	0.0	0.0	0.0	0.6	3.2	0.0	0.6	0.0	11.8
平均值					12.0	0.8	7.5	16.6	2.0	28.3	0.0	2.7	0.0	7.8	2.8	0.5	1.8	2.5	14.8
S203	S203-3	含粉砂白云岩	$E 3 2$ 盐下	4 486.40	9.7	1.8	12.5	16.4	28.7	0.0	0.0	0.2	0.0	0.0	5.2	0.0	9.8	0.0	15.7
S203	S203-4	泥质碳酸盐岩	$E 3 2$ 盐下	4 489.30	13.9	2.4	16.5	15.2	0.0	17.4	0.0	0.5	0.0	0.0	3.5	0.0	4.4	1.1	25.2
S203	S203-8	粉砂质白云岩	$E 3 2$ 盐下	4 500.00	13.5	2.1	10.1	14.7	31.9	0	0.0	0.1	0.0	0.0	2.6	0.0	1	6.1	17.9
S23	S23-1	含钙芒硝白云岩	$E 3 2$ 盐下	4 034.90	13.8	1.9	12.0	3.0	30.0	0.0	0.0	0.2	0.0	0.0	4.7	0.0	1.2	14.3	18.8
S23	S23-2	含粉砂碳酸盐岩	$E 3 2$ 盐下	4 036.00	6.6	0.8	6.1	30.7	0.0	25.2	0.0	0.1	0.0	0.0	1.2	0.0	23.0	0.6	5.8
S23	S23-3	含灰白云岩	$E 3 2$ 盐下	4 173.00	7.8	0.6	6.8	21.8	0.0	32.6	0.0	0.1	0.5	0.0	0.0	0.0	11.5	10.1	8.3
S25	S25-1	含灰白云岩	$E 3 2$ 盐下	4 177.50	2.2	0.3	5.2	11.7	60.2	0.0	0.0	6.4	0.0	0.0	1.0	0.0	1.5	6.2	5.3
S25	S25-4	含膏白云岩	$E 3 2$ 盐下	4 216.80	10.7	0.7	6.6	10.7	0.0	47.2	0.0	0.0	0.0	4.5	2.8	0.0	14.2	0.0	2.6
S28	S28-1	含泥碳酸盐岩	$E 3 2$ 盐下	3 990.00	15.8	1.1	10.1	22.5	0.0	16.5	0.0	0.0	0.0	0.4	4.8	0.0	4.4	0.3	24.1
S28	S28-3	泥质碳酸盐岩	$E 3 2$ 盐下	4 013.00	9.0	1.1	8.2	21.3	0.0	15.6	0.0	0.1	0.0	0.0	3.0	0.0	3.1	12.6	25.8
S30	S30-1	含粉砂白云岩	$E 3 2$ 盐下	4 081.00	10.2	1.5	7.0	11.3	0.0	41.7	0.0	0.0	12.9	5.5	3.4	0.0	1.6	0.0	4.9
S32X	S32X-1	含泥灰质白云岩	$E 3 2$ 盐下	4 132.00	10.6	1.0	5.6	26.4	0.0	32.8	0.0	0.3	0.0	0	4.1	0.0	0.6	0.5	18.1
S32X	S32X-5	含灰白云岩	$E 3 2$ 盐下	4 140.00	7.3	0.4	3.4	16.6	0.0	44.6	1.0	6.8	0.0	0	2.4	1.8	7.9	0.0	7.7
S43	S43-2	含膏碳酸盐岩	$E 3 2$ 盐下	3 931.28	7.5	1.0	5.3	16.6	0.0	19.2	2.6	0.0	1.9	0	2.4	0.0	19.8	17.6	6.1
SX28	SX28-1	含灰粉砂质泥岩	$E 3 2$ 盐下	4 165.00	11.2	2.3	13.9	16.5	0.0	10.2	0	0.2	0	0	3	0	3.6	5	34.2
平均值					10.0	1.3	8.6	17.0	10.1	20.2	0.2	1.0	1.0	0.7	2.9	0.1	7.2	5.0	14.7

Table 1 Statistics of the whole rock mineral content analysis by XRD of main reservoir of Oligocene in the Yingxi area

井号	样品编号	岩性描述	层位	深度 /m	石英	钾长石	斜长石	方解石	白云石	铁白云石	文石	菱铁矿	菱镁矿	石盐	黄铁矿	赤铁矿	硬石膏	钙芒硝	黏土矿物
S38	S38-1	深灰色含粉砂泥质白云岩	$E 3 2$ 盐间	2 794.62	14.8	0.9	6.5	8.4	16.2	17.5	0.0	0.0	0.0	0.6	2.4	0	4.1	2.8	25.8
S38	S38-3	深灰色泥质碳酸盐岩	$E 3 2$ 盐间	2 796.92	10.7	1.1	7.1	12.3	9.8	9.4	0.0	17.2	0.0	0.7	1.6	0	2.8	1.2	26.1
S38	S38-4	深灰色含粉砂碳酸盐岩	$E 3 2$ 盐间	2 800.72	11.4	1.2	8.4	28.2	0.0	18.8	0.0	6.7	0.0	0.5	2.5	0	3.7	1.1	17.5
S38	S38-5	灰色含泥粉砂质灰岩	$E 3 2$ 盐间	3 145.86	11.7	1.1	11.9	35.0	3.3	0.0	0.0	11.5	0.0	0.5	2.8	0	3.5	3.8	14.9
S38	S38-6	灰色含粉砂碳酸盐岩	$E 3 2$ 盐间	3 146.36	13.5	1.3	8.1	7.7	0.0	31.6	0.0	0.0	0.0	5.9	8.3	0	1.1	6.9	15.7
S37	S37-12	灰色含粉砂泥质碳酸盐岩	$E 3 2$ 盐间	2 692.02	12.6	1.1	8.9	25.0	0.0	17.8	0.0	0.0	0.0	1.1	2.7	0	0.9	1.8	28.2
S37	S37-13	灰色含云膏质粉砂岩	$E 3 2$ 盐间	2 697.07	22.9	1.5	11.3	2.7	0.0	14.9	0.0	5.4	0.0	1.3	1.7	0	7.8	19.3	11.4
S37	S37-14	石盐	$E 3 2$ 盐间	2 695.25	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	100.0	0.0	0	0.0	0.0	0.0
S1-2	S1-2-1	含灰白云岩	$E 3 2$ 盐间	2 757.70	10.7	1.1	7.6	17.2	0.0	50.0	0.0	0.0	0.0	0.4	2.9	0	0.6	0.0	9.6
S1-2	S1-2-2	含粉砂碳酸盐岩	$E 3 2$ 盐间	2 757.78	13.1	0.4	9.6	21.9	0.0	30.4	0.0	0.0	0.0	0.8	4.5	0	0.7	0.0	18.6
S1-2	S1-2-5	灰质白云岩	$E 3 2$ 盐间	2 758.10	9.8	0.4	6.2	25.5	0.0	42.7	0.0	0.0	0.0	1.2	0.0	3.5	0.4	0.0	10.4
S1-2	S1-2-7	灰质白云岩	$E 3 2$ 盐间	2 758.10	9.8	0.4	6.2	25.5	0.0	42.7	0.0	0.0	0.0	1.2	0.0	3.5	0.4	0.0	10.4
S1-2	S1-2-8	含粉砂白云岩	$E 3 2$ 盐间	2 758.19	11.3	0.4	5.5	13.3	0.0	52.8	0.0	0.0	0.0	0.9	5.7	0.0	0.3	0.0	9.8
S1-2	S1-2-9	粉砂质白云岩	$E 3 2$ 盐间	2 758.33	16.8	0.8	10.1	13.4	0.0	43.1	0.0	0.0	0.0	0.6	3.0	0.0	0.4	0.0	11.7
S1-2	S1-2-10	含粉砂白云岩	$E 3 2$ 盐间	2 758.39	11.6	0.4	5.6	13.5	0.0	52.6	0.0	0.0	0.0	0.6	3.2	0.0	0.6	0.0	11.8
平均值					12.0	0.8	7.5	16.6	2.0	28.3	0.0	2.7	0.0	7.8	2.8	0.5	1.8	2.5	14.8
S203	S203-3	含粉砂白云岩	$E 3 2$ 盐下	4 486.40	9.7	1.8	12.5	16.4	28.7	0.0	0.0	0.2	0.0	0.0	5.2	0.0	9.8	0.0	15.7
S203	S203-4	泥质碳酸盐岩	$E 3 2$ 盐下	4 489.30	13.9	2.4	16.5	15.2	0.0	17.4	0.0	0.5	0.0	0.0	3.5	0.0	4.4	1.1	25.2
S203	S203-8	粉砂质白云岩	$E 3 2$ 盐下	4 500.00	13.5	2.1	10.1	14.7	31.9	0	0.0	0.1	0.0	0.0	2.6	0.0	1	6.1	17.9
S23	S23-1	含钙芒硝白云岩	$E 3 2$ 盐下	4 034.90	13.8	1.9	12.0	3.0	30.0	0.0	0.0	0.2	0.0	0.0	4.7	0.0	1.2	14.3	18.8
S23	S23-2	含粉砂碳酸盐岩	$E 3 2$ 盐下	4 036.00	6.6	0.8	6.1	30.7	0.0	25.2	0.0	0.1	0.0	0.0	1.2	0.0	23.0	0.6	5.8
S23	S23-3	含灰白云岩	$E 3 2$ 盐下	4 173.00	7.8	0.6	6.8	21.8	0.0	32.6	0.0	0.1	0.5	0.0	0.0	0.0	11.5	10.1	8.3
S25	S25-1	含灰白云岩	$E 3 2$ 盐下	4 177.50	2.2	0.3	5.2	11.7	60.2	0.0	0.0	6.4	0.0	0.0	1.0	0.0	1.5	6.2	5.3
S25	S25-4	含膏白云岩	$E 3 2$ 盐下	4 216.80	10.7	0.7	6.6	10.7	0.0	47.2	0.0	0.0	0.0	4.5	2.8	0.0	14.2	0.0	2.6
S28	S28-1	含泥碳酸盐岩	$E 3 2$ 盐下	3 990.00	15.8	1.1	10.1	22.5	0.0	16.5	0.0	0.0	0.0	0.4	4.8	0.0	4.4	0.3	24.1
S28	S28-3	泥质碳酸盐岩	$E 3 2$ 盐下	4 013.00	9.0	1.1	8.2	21.3	0.0	15.6	0.0	0.1	0.0	0.0	3.0	0.0	3.1	12.6	25.8
S30	S30-1	含粉砂白云岩	$E 3 2$ 盐下	4 081.00	10.2	1.5	7.0	11.3	0.0	41.7	0.0	0.0	12.9	5.5	3.4	0.0	1.6	0.0	4.9
S32X	S32X-1	含泥灰质白云岩	$E 3 2$ 盐下	4 132.00	10.6	1.0	5.6	26.4	0.0	32.8	0.0	0.3	0.0	0	4.1	0.0	0.6	0.5	18.1
S32X	S32X-5	含灰白云岩	$E 3 2$ 盐下	4 140.00	7.3	0.4	3.4	16.6	0.0	44.6	1.0	6.8	0.0	0	2.4	1.8	7.9	0.0	7.7
S43	S43-2	含膏碳酸盐岩	$E 3 2$ 盐下	3 931.28	7.5	1.0	5.3	16.6	0.0	19.2	2.6	0.0	1.9	0	2.4	0.0	19.8	17.6	6.1
SX28	SX28-1	含灰粉砂质泥岩	$E 3 2$ 盐下	4 165.00	11.2	2.3	13.9	16.5	0.0	10.2	0	0.2	0	0	3	0	3.6	5	34.2
平均值					10.0	1.3	8.6	17.0	10.1	20.2	0.2	1.0	1.0	0.7	2.9	0.1	7.2	5.0	14.7

Table 2 Statistics of micro area composition analysis by electron probe of main salt minerals of Oligocene in the Yingxi area

井号	深度 /m	探针点	Na₂O	MgO	Al₂O₃	SiO₂	SO₃	K₂O	CaO	MnO	FeO	SrO	BaO	Total	矿物名称
S37	2 696.03	8	52.571	0.091	0.242	0.568	0.134	0.067	0.201	0.008	0.095	0.012	0	53.988	石盐
S37	2 696.03	9	53.967	0	0.122	0.289	0.025	0.036	0.096	0	0.029	0	0.003	54.567	石盐
S37	2 696.03	10	51.714	0.168	0.352	0.743	0.116	0.053	0.337	0.045	0.154	0.009	0.012	53.702	石盐
S37	2 696.03	11	50.833	0.248	0.594	1.233	0.129	0.082	0.391	0.047	0.131	0	0	53.689	石盐
平均值			52.271	0.127	0.328	0.708	0.101	0.060	0.256	0.025	0.102	0.005	0.004	53.987	/
S203	4 496.9	3	0.165	0.007	0.278	0.672	39.015	0.006	34.503	0.02	0.034	0.38	0.005	75.083	硬石膏
S203	4 496.9	4	0.02	0.023	0.077	0.419	40.747	0.009	35.829	0	0	0.283	0	77.406	硬石膏
S203	4 496.9	5	0.128	0.014	0.068	0.237	39.939	0.029	36.838	0.002	0.029	0.112	0.009	77.406	硬石膏
S203	4 496.9	6	0.106	0.024	0.318	0.73	38.956	0.022	35.326	0	0.058	0.265	0	75.805	硬石膏
S23	4 036	6	0.196	0.11	0.518	1.399	46.056	0.107	36.982	0.025	0.137	0.855	0.023	86.408	硬石膏
S23	4 036	7	0.026	0.008	0	0.062	42.157	0	39.132	0	0	0.947	0.039	82.37	硬石膏
S23	4 036	10	0.091	0.041	0.426	1.693	44.264	0.264	35.981	0.04	0.01	0.379	0	83.188	硬石膏
S23	4 036	11	0.044	0.038	0.125	0.718	39.136	0.026	38.152	0	0.077	0.194	0.041	78.548	硬石膏
S23	4 036	13	0.091	0.005	0.014	0.492	43.123	0.048	40.956	0.016	0	0.546	0	85.291	硬石膏
S23	4 173	2	0.041	0.005	0.008	0.099	42.518	0	35.404	0	0.01	0.521	0.001	78.605	硬石膏
S23	4 173	3	0.043	0.011	0.003	0.039	44.484	0	35.61	0.047	0	0.53	0.002	80.769	硬石膏
S23	4 173	7	0.022	0.026	0	0.077	45.182	0	34.282	0.017	0	0.117	0	79.724	硬石膏
S23	4 173	8	0.048	0.053	0.713	1.319	42.112	0.133	32.613	0.015	0	0.465	0	77.471	硬石膏
S23	4 173	9	0.019	1.074	0.022	0.072	32.108	0	34.395	0.018	0.124	0.106	0	67.939	硬石膏
S23	4 173	13	0.259	2.255	0.37	1.434	33.206	0.067	31.282	0.006	0.486	0.087	0.021	69.473	硬石膏
S23	4 173	14	0.058	0.021	0.046	0.115	42.116	0.003	32.223	0	0.014	0.213	0.011	74.819	硬石膏
S23	4 173	15	0.012	0.002	0	0.015	41.118	0	33.873	0	0.073	0	0.002	75.094	硬石膏
S32X	4 132	8	0.057	0.086	0.313	0.309	38.59	0.061	35.285	0	0.01	0.17	0	74.883	硬石膏
S32X	4 132	9	0.043	0.022	0.074	0.456	34.952	0.01	33.698	0	0.046	0.307	0.035	69.643	硬石膏
S32X	4 132	16	0.024	0.048	0.558	1.527	41.22	0.097	34.897	0	0.224	0.276	0	78.87	硬石膏
S32X	4 132	17	0.058	0.156	0.295	1.479	41.446	0.094	35.323	0.008	0.122	0.628	0	79.609	硬石膏
S32X	4 133.48	10	0.022	0.382	0.089	0.306	38.286	0.008	34.202	0.029	0.142	0.079	0	73.545	硬石膏
S32X	4 133.48	11	0.122	0.414	0.262	0.889	41.867	0.024	35.025	0	0.089	0.045	0.034	78.77	硬石膏
平均值			0.074	0.210	0.199	0.633	40.548	0.044	35.296	0.011	0.073	0.326	0.010	77.423	/
S23	4 034.9	2	7.446	0.087	0.08	0.224	41.654	0.004	32.942	0	0	0.367	0.016	82.821	钙芒硝
S23	4 034.9	3	7.448	0.015	0	0.031	42.185	0.026	33.501	0.009	0	0.129	0.031	83.375	钙芒硝
S23	4 034.9	4	8.819	0.028	0.025	0.138	45.561	0	33.424	0.081	0	0.283	0	88.359	钙芒硝
S23	4 034.9	5	8.917	0.084	0.329	0.267	41.828	0.021	31.709	0	0.054	0.085	0.006	83.299	钙芒硝
S23	4 036	2	7.376	0.115	0.138	0.444	43.061	0.062	32.48	0.008	0.096	0.07	0	83.85	钙芒硝
S23	4 036	3	7.245	0.082	0.134	0.353	41.524	0.01	31.825	0.013	0	0.339	0	81.526	钙芒硝
S23	4 036	4	5.576	0.218	0.465	1.39	42.489	0.02	33.464	0.048	0.166	0.166	0	84.002	钙芒硝
S23	4 173	5	7.175	0.029	0	0	39.449	0.007	31.338	0.037	0.033	0.164	0	78.232	钙芒硝
S23	4 173	6	7.151	0.033	0.065	0.732	41.169	0.004	30.263	0	0.027	0.159	0	79.605	钙芒硝
S23	4 173	10	5.718	0.577	0.688	1.292	38.295	0.034	28.501	0.026	0.07	0.185	0	75.386	钙芒硝
S23	4 173	11	8.214	0.049	0.026	0.284	39.593	0	28.978	0.029	0.075	0.077	0.018	77.343	钙芒硝
平均值			7.371	0.120	0.177	0.469	41.528	0.017	31.675	0.023	0.047	0.184	0.006	81.618	/
S32X	4 135	1	0.011	0.158	0	0.289	29.39	0.003	1.346	0.027	0.065	36.297	9.025	76.61	天青石
S32X	4 135	2	0.124	0.442	0.744	3.248	26.135	0.275	1.892	0	0.127	30.592	8.141	71.721	天青石
S32X	4 135	3	0.059	0.132	0	0.391	28.159	0.001	1.288	0	0.03	34.318	10.531	74.908	天青石
S32X	4 135	4	0.027	0.005	0	0.027	23.971	0	0.285	0	0	31.726	8.404	64.445	天青石
S32X	4 135	5	0.104	0.322	0	2.56	28.023	0	3.556	0	0.085	29.887	11.717	76.254	天青石
平均值			0.065	0.212	0.149	1.303	27.136	0.056	1.673	0.005	0.061	32.564	9.564	72.788	/

Table 2 Statistics of micro area composition analysis by electron probe of main salt minerals of Oligocene in the Yingxi area

井号	深度 /m	探针点	Na₂O	MgO	Al₂O₃	SiO₂	SO₃	K₂O	CaO	MnO	FeO	SrO	BaO	Total	矿物名称
S37	2 696.03	8	52.571	0.091	0.242	0.568	0.134	0.067	0.201	0.008	0.095	0.012	0	53.988	石盐
S37	2 696.03	9	53.967	0	0.122	0.289	0.025	0.036	0.096	0	0.029	0	0.003	54.567	石盐
S37	2 696.03	10	51.714	0.168	0.352	0.743	0.116	0.053	0.337	0.045	0.154	0.009	0.012	53.702	石盐
S37	2 696.03	11	50.833	0.248	0.594	1.233	0.129	0.082	0.391	0.047	0.131	0	0	53.689	石盐
平均值			52.271	0.127	0.328	0.708	0.101	0.060	0.256	0.025	0.102	0.005	0.004	53.987	/
S203	4 496.9	3	0.165	0.007	0.278	0.672	39.015	0.006	34.503	0.02	0.034	0.38	0.005	75.083	硬石膏
S203	4 496.9	4	0.02	0.023	0.077	0.419	40.747	0.009	35.829	0	0	0.283	0	77.406	硬石膏
S203	4 496.9	5	0.128	0.014	0.068	0.237	39.939	0.029	36.838	0.002	0.029	0.112	0.009	77.406	硬石膏
S203	4 496.9	6	0.106	0.024	0.318	0.73	38.956	0.022	35.326	0	0.058	0.265	0	75.805	硬石膏
S23	4 036	6	0.196	0.11	0.518	1.399	46.056	0.107	36.982	0.025	0.137	0.855	0.023	86.408	硬石膏
S23	4 036	7	0.026	0.008	0	0.062	42.157	0	39.132	0	0	0.947	0.039	82.37	硬石膏
S23	4 036	10	0.091	0.041	0.426	1.693	44.264	0.264	35.981	0.04	0.01	0.379	0	83.188	硬石膏
S23	4 036	11	0.044	0.038	0.125	0.718	39.136	0.026	38.152	0	0.077	0.194	0.041	78.548	硬石膏
S23	4 036	13	0.091	0.005	0.014	0.492	43.123	0.048	40.956	0.016	0	0.546	0	85.291	硬石膏
S23	4 173	2	0.041	0.005	0.008	0.099	42.518	0	35.404	0	0.01	0.521	0.001	78.605	硬石膏
S23	4 173	3	0.043	0.011	0.003	0.039	44.484	0	35.61	0.047	0	0.53	0.002	80.769	硬石膏
S23	4 173	7	0.022	0.026	0	0.077	45.182	0	34.282	0.017	0	0.117	0	79.724	硬石膏
S23	4 173	8	0.048	0.053	0.713	1.319	42.112	0.133	32.613	0.015	0	0.465	0	77.471	硬石膏
S23	4 173	9	0.019	1.074	0.022	0.072	32.108	0	34.395	0.018	0.124	0.106	0	67.939	硬石膏
S23	4 173	13	0.259	2.255	0.37	1.434	33.206	0.067	31.282	0.006	0.486	0.087	0.021	69.473	硬石膏
S23	4 173	14	0.058	0.021	0.046	0.115	42.116	0.003	32.223	0	0.014	0.213	0.011	74.819	硬石膏
S23	4 173	15	0.012	0.002	0	0.015	41.118	0	33.873	0	0.073	0	0.002	75.094	硬石膏
S32X	4 132	8	0.057	0.086	0.313	0.309	38.59	0.061	35.285	0	0.01	0.17	0	74.883	硬石膏
S32X	4 132	9	0.043	0.022	0.074	0.456	34.952	0.01	33.698	0	0.046	0.307	0.035	69.643	硬石膏
S32X	4 132	16	0.024	0.048	0.558	1.527	41.22	0.097	34.897	0	0.224	0.276	0	78.87	硬石膏
S32X	4 132	17	0.058	0.156	0.295	1.479	41.446	0.094	35.323	0.008	0.122	0.628	0	79.609	硬石膏
S32X	4 133.48	10	0.022	0.382	0.089	0.306	38.286	0.008	34.202	0.029	0.142	0.079	0	73.545	硬石膏
S32X	4 133.48	11	0.122	0.414	0.262	0.889	41.867	0.024	35.025	0	0.089	0.045	0.034	78.77	硬石膏
平均值			0.074	0.210	0.199	0.633	40.548	0.044	35.296	0.011	0.073	0.326	0.010	77.423	/
S23	4 034.9	2	7.446	0.087	0.08	0.224	41.654	0.004	32.942	0	0	0.367	0.016	82.821	钙芒硝
S23	4 034.9	3	7.448	0.015	0	0.031	42.185	0.026	33.501	0.009	0	0.129	0.031	83.375	钙芒硝
S23	4 034.9	4	8.819	0.028	0.025	0.138	45.561	0	33.424	0.081	0	0.283	0	88.359	钙芒硝
S23	4 034.9	5	8.917	0.084	0.329	0.267	41.828	0.021	31.709	0	0.054	0.085	0.006	83.299	钙芒硝
S23	4 036	2	7.376	0.115	0.138	0.444	43.061	0.062	32.48	0.008	0.096	0.07	0	83.85	钙芒硝
S23	4 036	3	7.245	0.082	0.134	0.353	41.524	0.01	31.825	0.013	0	0.339	0	81.526	钙芒硝
S23	4 036	4	5.576	0.218	0.465	1.39	42.489	0.02	33.464	0.048	0.166	0.166	0	84.002	钙芒硝
S23	4 173	5	7.175	0.029	0	0	39.449	0.007	31.338	0.037	0.033	0.164	0	78.232	钙芒硝
S23	4 173	6	7.151	0.033	0.065	0.732	41.169	0.004	30.263	0	0.027	0.159	0	79.605	钙芒硝
S23	4 173	10	5.718	0.577	0.688	1.292	38.295	0.034	28.501	0.026	0.07	0.185	0	75.386	钙芒硝
S23	4 173	11	8.214	0.049	0.026	0.284	39.593	0	28.978	0.029	0.075	0.077	0.018	77.343	钙芒硝
平均值			7.371	0.120	0.177	0.469	41.528	0.017	31.675	0.023	0.047	0.184	0.006	81.618	/
S32X	4 135	1	0.011	0.158	0	0.289	29.39	0.003	1.346	0.027	0.065	36.297	9.025	76.61	天青石
S32X	4 135	2	0.124	0.442	0.744	3.248	26.135	0.275	1.892	0	0.127	30.592	8.141	71.721	天青石
S32X	4 135	3	0.059	0.132	0	0.391	28.159	0.001	1.288	0	0.03	34.318	10.531	74.908	天青石
S32X	4 135	4	0.027	0.005	0	0.027	23.971	0	0.285	0	0	31.726	8.404	64.445	天青石
S32X	4 135	5	0.104	0.322	0	2.56	28.023	0	3.556	0	0.085	29.887	11.717	76.254	天青石
平均值			0.065	0.212	0.149	1.303	27.136	0.056	1.673	0.005	0.061	32.564	9.564	72.788	/

Fig.4 Core photographs, microscopic features of salt mineral filled fractures of Oligocene in the Yingxi area

Fig.5 The distribution characteristics of salt layer and geologic section of hydrocarbon accumulation of E 3 2 reservoir of Oligocene in the Yingxi area

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