Journal of Tropical Oceanography >
Thermal evolution of source rock and prediction of petroleum resources potential in Baiyun Depression, deep-water area of the northern South China Sea
Received date: 2016-05-06
Request revised date: 2016-06-08
Online published: 2017-01-19
Supported by
National Science and Technology Major Projects “Key Techniques in the Deep Ocean Oil and Gas Exploration” (2008ZX05025、2011ZX05025)
Copyright
Based on the data of drilling, logging, seismic, geology and basin modeling, we analyzed the characteristics of geothermal, source rock maturation, hydrocarbon expulsion, and accumulation coefficient by using the analogy and genetic methods. Then, prediction of petroleum resources potential in Baiyun depression is carried out. The results show that the Baiyun Depression presents high geothermal gradient, ranging from 34 to 67℃·km-1 and with an average of 40℃·km-1, which is favorable for organic matter maturation and hydrocarbon generation. Each source rock has been in the stage of mature or post mature, and the source rock maturation increases from the top formation of Zhuhai to the bottom formation of Wenchang; the area of post mature is 53.7% in the bottom formation of Wenchang. The strength of gas expulsion is bigger than the strength of oil expulsion, and the upper formation of Enping is the major formation of hydrocarbon expulsion. The hydrocarbon expulsion of three source rocks is 1143×108 m3, and prediction of petroleum resources potential in the Baiyun Depression is 25.2×108 m3 combining the accumulation coefficients of oil and gas.
WANG Ke , ZHANG Gongcheng , YANG Haizhang , TONG Zhigang , YANG Shuchun . Thermal evolution of source rock and prediction of petroleum resources potential in Baiyun Depression, deep-water area of the northern South China Sea[J]. Journal of Tropical Oceanography, 2017 , 36(1) : 25 -34 . DOI: 10.11978/2016047
Fig. 1 Tectonic units and the main well of the Baiyun Sag图1 白云凹陷主要钻井及构造分布图 |
Fig. 2 Stratigraphic column of the Baiyun Sag图2 白云凹陷地层柱状图 |
Fig. 3 Geothermal characteristics of the Baiyun Sag图3 白云凹陷钻井地层测试温度、地温梯度与深度关系图 |
Fig. 4 Map of geothermal gradient of the Baiyun Sag图4 白云凹陷地温梯度(单位: ℃·km-1)分布图 |
Tab. 1 Statistics of geothermal gradient of the Baiyun Sag表1 白云凹陷不同构造位置地温梯度统计表 |
构造单元 | 单井名称 | 门限深度/m | 地温梯度/(℃·km-1) |
---|---|---|---|
凹陷中部 | d | 2530 | 37 |
凹陷北部 | c | 2139 | 38 |
凹陷南部 | e | 3325 | 48 |
凹陷东部 | g | 2453 | 45 |
凹陷西部 | a | 1795 | 40 |
Fig. 5 The maturity evolution of the organic matter (left) and the contrast of observed temperature and simulated temperature (right) of the Baiyun Sag图5 代表性单井成熟度演化史及模拟值与实测值拟合对比图 |
Tab. 2 Statistics of maturity evolution of the Baiyun Sag表2 白云凹陷代表性单井成熟度演化时间统计表 |
井号 | 演化时间/Ma | ||||
---|---|---|---|---|---|
低成熟(Ro=0.5%) | 成熟(Ro=0.7%) | 高成熟(Ro=1.3%) | 过成熟(Ro=2.0%) | ||
d | 恩平组 | 33.2 | 30.5 | 22.9 | 18.5 |
文昌组 | 37.4 | 36.4 | 33.8 | 31.4 | |
c | 恩平组 | 20.3 | 10.4 | / | / |
文昌组 | 23.0 | 12.5 | / | / | |
e | 恩平组 | 30.3 | 26.7 | 7.1 | / |
文昌组 | 36.5 | 29.4 | 19.1 | 2.9 | |
g | 恩平组 | 9.1 | / | / | / |
文昌组 | 10.4 | / | / | / | |
a | 恩平组 | 22.8 | 16.7 | 5.2 | / |
文昌组 | 31.1 | 20.2 | 9.6 | / |
Fig. 6 Maturity map of source rock of the Baiyun Sag at different times图6 白云凹陷各烃源岩不同时刻成熟度平面图 |
Fig. 7 Ration of generation and expulsion of Kerogen II图7 典型II型干酪根生烃及排烃比例 |
Fig. 8 Thickness map of source rock of the Baiyun Sag图8 白云凹陷各烃源岩厚度图 |
Fig. 9 Expulsion intensity map of source rock of the Baiyun Sag图9 白云凹陷各烃源岩排油、排气及排烃强度平面图 |
Tab. 3 Statistical expulsion quantity of source rock of the Baiyun Sag表3 白云凹陷各烃源岩排烃量统计表 |
凹陷 | 层位 | 油/(×108m3) | 气/(×1011m3) | ||||
---|---|---|---|---|---|---|---|
P10 | P50 | P90 | P10 | P50 | P90 | ||
白云凹陷 | 珠海组 | 0 | 0 | 0 | 67.0 | 34.4 | 13.4 |
恩平组上段 | 35.9 | 24.5 | 14.5 | 613.6 | 533.0 | 458.6 | |
恩平组中段 | 0.3 | 0.2 | 0.1 | 74.1 | 67.7 | 61.6 | |
恩平组下段 | 0.3 | 0.2 | 0.1 | 245.7 | 229.6 | 212.8 | |
恩平组 | 36.5 | 24.8 | 14.7 | 933.4 | 830.2 | 733.0 | |
文昌组 | 85.4 | 77.1 | 69.5 | 188.4 | 176.7 | 165.4 |
Fig. 10 Trap and fetch area of oil field J图10 J油气田圈闭及其对应汇聚区范围 |
Tab. 4 Statistical clustering coefficient of oil & gas field J表4 J油气田聚集系数统计表 |
探明地质储量 | 排烃量 | 聚集系数/% | |
---|---|---|---|
石油/(×104m3) | 115.93 | 24161.16 | 0.48 |
天然气/(×108m3) | 153.45 | 6190.89 | 2.48 |
Tab. 5 Statistical clustering coefficient of other oil & gas fields表5 白云凹陷各油气田聚集系数统计表 |
油气田 名称 | 聚集系数 /% | 油气田 名称 | 聚集系数/% | ||
---|---|---|---|---|---|
G | 石油 | 15.62 | N | 石油 | / |
天然气 | / | 天然气 | 5.13 | ||
E | 石油 | 5.65 | C | 石油 | 0.45 |
天然气 | 2.43 | 天然气 | 0.23 | ||
J | 石油 | 0.48 | Q | 石油 | / |
天然气 | 2.48 | 天然气 | 1.51 | ||
B | 石油 | 0.37 | T | 石油 | / |
天然气 | 0.30 | 天然气 | 1.79 | ||
P | 石油 | 0.14 | D | 石油 | / |
天然气 | 0.20 | 天然气 | 0.10 | ||
O | 石油 | / | M | 石油 | / |
天然气 | 2.45 | 天然气 | 1.70 | ||
I | 石油 | 0.92 | |||
天然气 | 8.52 |
Tab. 6 Statistical resource of the Baiyun Sag表6 白云凹陷预测资源量统计表 |
资源量 | |||
---|---|---|---|
最大 | 最小 | 平均 | |
油/×108m3 | 15.0 | 0.4 | 3.4 |
气/×1011m3 | 77.2 | 2.3 | 21.8 |
合计/×108m3油当量 | 92.2 | 2.7 | 25.2 |
The authors have declared that no competing interests exist.
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