Turbidity Channel Sandstone Reservoir Characterization in Baobab North Oilfield,Bongor Basin

Abstract

Abstract:

In order to study the architecture characteristics and sediment mechanism of the turbidity channel sandstone, this article takes the turbidity channel sandstone of Layer P of Baobab North Oilfields in Bongor Basin for example. Under the guidance of sedimentary mechanism, the sedimentary environment of the Layer P is confirmed. The types and the structural features of the single turbidity channel sandstone are studied. And the architecture characteristics of the mud layers in the single turbidity channel sandstone are analyzed. Based on the research mentioned above, there are three kinds of single turbidity channel in the Layer P. The Ⅰ type turbidity channels have a positive rhythm of the size distribution, and its GR and SP loggings are bell-shaped. The Ⅱ type turbidity channels have an even rhythm of the size distribution, and their GR and SP loggings are box-shaped. The Ⅲ type turbidity channels have a negative rhythm of the size distribution, and their GR and SP loggings are funnel-shaped. There are three kinds of mud interlayers in the single turbidity channel. The continuous type is preserved well and its loggings are near the baseline. Its length is between 100 m and 450 m along river flow direction. Its width is between 70 m and 300 m in the vertical direction of the river flow. Its thickness is between 0.3 m and 0.8 m. Its distribution frequency is between 0.13 and 0.7. Its distribution density is between 0.04 and 0.25. The discontinuous type is hardly preserved and its loggings are far away from the baseline. Its length is between 50 m and 250 m along river flow direction. Its width is between 40 m and 200 m in the vertical direction of the river flow. Its thickness is between 0.15 m and 0.5 m. Its distribution frequency is between 0.12 and 0.4. Its distribution density is between 0.04 and 0.14. The complex type is mixed by both of the continuous type and discontinuous. Its length is between 80 m and 320 m along river flow direction. Its width is between 55 m and 240 m in the vertical direction of the river flow. Its thickness is between 0.25m and 0.6m. Its distribution frequency is between 0.12 and 0.45. Its distribution density is between 0.04 and 0.18.

Key words: Bongor Basin, Baobab North Oilfield, turbidity channel, architecture characterization, remaining oil distribution

CLC Number:

TE122.2

WEN Guangyao, WU Xianghong, LI Xianbing, GAO Chao, LIANG Hongwei. Turbidity Channel Sandstone Reservoir Characterization in Baobab North Oilfield,Bongor Basin[J]. Geoscience, 2017, 31(03): 555-564.

Figures/Tables 12

Fig.1 Structural map of the Baobab North Oilfield

Fig.2 Cumulative probability curve of the Baobab North Oilfield

Fig.3 C-M of the Baobab North Oilfield

Fig.4 Core photographs of the Baobab North Oilfield

Fig.5 Three types of single channel in the Baobab North Oilfield

Fig.6 Microfacies map of Layer PI1-2 in the Baobab North Oilfield

Fig.7 Microfacies map of Layer PI1-3 in the Baobab North Oilfield

Fig.8 Microfacies map of Layer PI1-4 in the Baobab North Oilfield

Fig.9 Vertical distribution characteristics of channels in a channel system, Baobab North Oilfield

Fig.10 Logging characteristics of the mud interlayers in the single channel, Baobab North Oilfield, Well Baobab N8

Fig.11 Complex type mud interlayers of the single channel in the Baobab North Oilfield

Table 1 Statistic parameter of the mud interlayers in the single channel, Baobab North Oilfield

类型	厚度/m	夹层密度 m/m	夹层频率个/m	顺水流方向
类型	厚度/m	夹层密度 m/m	夹层频率个/m	长度/m	宽度/m
间断型	0.15~0.5	0.04~0.14	0.12~0.40	50~250	40~200
复杂型	0.25~0.6	0.04~0.18	0.12~0.45	80~320	55~240
连续型	0.30~0.8	0.04~0.25	0.13~0.70	100~450	70~300

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