A new method for identification of flow units of sandstone reservoir based on reservoir performance and its application in the Akshabulak oilfield, Kazakhstan

doi:10.13745/j.esf.sf.2022.10.16

Abstract

Abstract:

Taking an example of the massive sandstone of layer J-Ⅲ, Akshabulak oilfield, southern Turgay Basin, Kazakhstan, we propose a new method to identify flow units based on reservoir performance ratings. First, four performance ratings, “excellent”, “good”, “moderate” and “poor”, are assigned according to reservoir production profile and daily well output under similar working conditions. Then, taking the reservoir performance rating as the discriminant function, based on core analysis results, seven types of reservoir quality indicators are selected for clustering analysis. Finally, based on the quality indicator values and well-log interpretation data, the flow units are delineated into four types, “high-flow”, “relatively high-flow”, “moderate-flow” and “low-flow”, according to water flow levels, by neural network clustering. Statistical analysis results show that the reservoir-quality indicator values correlate positively with reservoir performance ratings, therefore it is reasonable to identify flow units according to performance ratings. Our study indicates that the development pattern of flow units determines the reservoir performance: when flow units of different types are developed, water tends to flow towards units with higher flow levels causing uneven flooding in the vertical direction; horizontally, areas with high-level flow units are flooded preferentially causing significant uneven advancements of waterflooding front. We propose, therefore, to control vertical waterflooding by water plugging at high-level flow units and allow planar natural waterflooding combined with water injection to achieve stable and high-efficiency reservoir development.

Key words: South Turgay Basin, massive sandstone, flow unit identification, reservoir performance rating, residue oil characterization

CLC Number:

WANG Jincai, FAN Zifei, ZHAO Lun, CHEN Yefei, ZHANG Angang, ZHANG Xiangzhong, GUO Xuejing, LI Yi. A new method for identification of flow units of sandstone reservoir based on reservoir performance and its application in the Akshabulak oilfield, Kazakhstan[J]. Earth Science Frontiers, 2023, 30(4): 88-99.

Figures/Tables 17

Fig.1 Structural location and stratigraphic features of the Akshabulak oilfield

Fig.2 Akshabulak oilfield structural features and drill cores

Fig.3 Vertical heterogeneity and liquid production (water absorption) characteristics of layer J-Ⅲ

Fig.4 Sand body types and vertical features of layer J-Ⅲ

Fig.5 Vertical seismic attributes and sedimentary characteristics of J-Ⅲ delta sand bodies

Fig.6 Composite diagram showing seismic attributes and depositional features of layer J-Ⅲ

Fig.7 Flow chart of flow unit identification based on reservoir performance rating

Fig.8 Single well production distribution plot for layer J-Ⅲ under similar working conditions (325 data from 28 wells)

Fig.9 Positive correlation relationship between reservoir-quality indicator values and reservoir performance ratings as the basis for flow-unit identification

Table 1 Reservoir-quality indicator values under different reservoir performance ratings(315 samples)

储层动用程度类型	K/(10^-3 μm²)	Ф	V_sh	R₃₅/μm	RQI/μm	FZI	Ф_z
好	1 698.0	0.29	0.04	18.22	2.25	5.51	0.40
较好	1 198.8	0.28	0.05	15.05	1.83	4.76	0.38
中等	412.1	0.26	0.05	11.42	1.36	3.83	0.35
差	56.5	0.24	0.06	8.27	0.96	3.03	0.31

Fig.10 Results of flow-unit delineation by neural network clustering

Table 2 Reservoir-quality indicator values under different flow unit types (238 well data)

流动单元	K/(10^-3 μm²)	Ф	V_sh	R₃₅/μm	RQI/μm	FZI	Ф_z
A	2 431.4	0.30	0.05	23.55	2.95	6.68	0.44
B	1 182.2	0.27	0.06	13.91	1.69	4.58	0.37
C	344.5	0.24	0.07	7.89	0.92	2.90	0.31
D	51.5	0.18	0.10	3.69	0.41	1.89	0.22

Fig.11 Planar thicknesses of different flow units and dominant flow unit distribution in layer J-Ⅲ

Table 3 Reservoir performance characteristics of different flow unit types

流动单元	渗透率/m	原始含水饱和度/%	剩余油饱和度/%	水驱油效率/%
A	>6 000	0.07	0.1	0.89
B	>2 500~6 000	0.105	0.1	0.89
C	>1 000~2 500	0.14	0.15	0.83
D	2~1 000	0.17	0.15	0.82

Fig.12 Distributions of recoverable reserves (a) and residual oil saturation levels (b) in different types of flow units in layer J-Ⅲ in the study area

Table 4 Reservoir performance data for different flow unit types based on numerical simulation

流动单元	平均厚度/m	储量丰度/(10⁴t·km^-2)		含油饱和度/%		采出程度/%
流动单元	平均厚度/m	原始	剩余	原始	剩余	采出程度/%
J-Ⅲ层	13	75.4	31.7	0.87	0.39	0.58
A	8	50.6	20.1	0.87	0.38	0.60
B	11	51.8	22.3	0.87	0.41	0.57
C	11	51.9	23.2	0.87	0.46	0.55
D	8	37.1	17.7	0.87	0.49	0.52

Fig.13 Variation of waterflooding-front advancing speed in layer J-Ⅲ in the study area

References 29

[1]	范乐元, 吴嘉鹏, 刁宛, 等. 断陷湖盆浅水三角洲沉积特征: 以Muglad盆地Unity凹陷Aradeiba组为例[J]. 地学前缘, 2021, 28(1): 155-166. DOI
[2]	朱筱敏, 董艳蕾, 刘成林, 等. 中国含油气盆地沉积研究主要科学问题与发展分析[J]. 地学前缘, 2021, 28(1): 1-11. DOI
[3]	何登发, 马永生, 刘波, 等. 中国含油气盆地深层勘探的主要进展与科学问题[J]. 地学前缘, 2019, 26(1): 1-12. DOI
[4]	赵伦, 王进财, 陈礼, 等. 砂体叠置结构及构型特征对水驱规律的影响: 以哈萨克斯坦南图尔盖盆地Kumkol油田为例[J]. 石油勘探与开发, 2014, 41(1): 86-94.
[5]	WANG J C, ZHAO L, ZHANG X Z, et al. Influence of meandering river sandstone architecture on waterflooding mechanisms: a case study of the M-I layer in the Kumkol Oilfield, Kazakhstan[J]. Petroleum Science, 2014, 11(1): 81-88. DOI URL
[6]	赵伦, 梁宏伟, 张祥忠, 等. 砂体构型特征与剩余油分布模式: 以哈萨克斯坦南图尔盖盆地Kumkol South油田为例[J]. 石油勘探与开发, 2016, 43(3): 433-441. DOI
[7]	刘宝珺, 余光明, 陈成生. 西藏日喀则地区第三系大竹卡组砾质扇三角洲: 片状颗粒流沉积[J]. 沉积与特提斯地质, 1990, 10(1): 1-11.
[8]	HEARN C L, EBANKS W J Jr, TYE R S, et al. Geological factors influencing reservoir performance of the Hartzog Draw field, Wyoming[J]. Journal of Petroleum Technology, 2019, 36(8): 1335-1344. DOI URL
[9]	EBANKS W J Jr. Flow unit concept: integrated approach to reservoir description for engineering projects[J]. AAPG Bulletin, 1987, 71(5):551-552.
[10]	MOSS A K, JING X D, ARCHER J S. Laboratory investigation of wettability and hysteresis effects on resistivity index and capillary pressure characteristics[J]. Journal of Petroleum Science and Engineering, 1999, 24(2/3/4): 231-242. DOI URL
[11]	岳大力, 吴胜和, 林承焰. 碎屑岩储层流动单元研究进展[J]. 中国科技论文在线, 2008, 3(11):810-818.
[12]	AL-JAWAD S N, SALEH A H, AL-DABAJ A A A, et al. Reservoir flow unit identification of the Mishrif Formation in North Rumaila Field[J]. Arabian Journal of Geosciences, 2014, 7(7): 2711-2728. DOI URL
[13]	ELNAGGAR O M. A new processing for improving permeability prediction of hydraulic flow units, Nubian Sandstone, Eastern Desert, Egypt[J]. Journal of Petroleum Exploration and Production Technology, 2018, 8(3): 677-683. DOI
[14]	YUSUF I, PADMANABHAN E. Impact of rock fabric on flow unit characteristics in selected reservoir sandstones from West Baram Delta Offshore, Sarawak[J]. Journal of Petroleum Exploration and Production Technology, 2019, 9(3): 2149-2164. DOI
[15]	SHEDID S A. A new technique for identification of flow units of shaly sandstone reservoirs[J]. Journal of Petroleum Exploration and Production Technology, 2018, 8(2): 495-504. DOI URL
[16]	LOPEZ B, AGUILERA R. Flow units in shale condensate reservoirs[J]. SPE Reservoir Evaluation and Engineering, 2016, 19(3):450-465. DOI URL
[17]	MODE A W, ANYIAM O A, ONWUCHEKWA C N. Flow unit characterization: key to delineating reservoir performance in “Aqua-Field”, Niger Delta, Nigeria[J]. Journal of the Geological Society of India, 2014, 84(6): 701-708. DOI URL
[18]	KASSAB M A, TEAMA M A. Hydraulic flow unit and facies analysis integrated study for reservoir characterisation: a case study of Middle Jurassic rocks at Khashm El-Galala, Gulf of Suez, Egypt[J]. Arabian Journal of Geosciences, 2018, 11(12): 294. DOI
[19]	康立明, 任战利. 多参数定量研究流动单元的方法: 以鄂尔多斯盆地W93井区为例[J]. 吉林大学学报(地球科学版), 2008, 38(5): 749-756.
[20]	李君君, 王志章, 王征, 等. 扶余油田泉三段储层流动单元划分及应用[J]. 科技导报, 2014, 32(23): 22-27.
[21]	张添锦, 张海, 李鹏程. 基于FZI的致密砂岩渗流特征分析[J]. 西安科技大学学报, 2017, 37(3):370-376.
[22]	罗超, 罗水亮, 窦丽玮, 等. 基于高分辨率层序地层的储层流动单元研究[J]. 中国石油大学学报(自然科学版), 2016, 40(6):22-32.
[23]	万琼华, 吴胜和, 陈亮, 等. 基于深水浊积水道构型的流动单元分布规律[J]. 石油与天然气地质, 2015, 36(2): 306-313.
[24]	郑香伟, 吴健, 何胜林, 等. 基于流动单元的砂砾岩储层渗透率测井精细评价[J]. 吉林大学学报(地球科学版), 2016, 46(1): 286-294.
[25]	王志松, 欧成华, 侯庆杰, 等. H油田延6段储层流动单元划分与剩余油分布研究[J]. 重庆科技学院学报(自然科学版), 2014, 16(4):13-16, 25.
[26]	YIN T J, ZHANG C M, ZHANG S F, et al. Estimation of reservoir and remaining oil prediction based on flow unit analysis[J]. Science in China Series D: Earth Sciences, 2009, 52(增刊1): 120-127.
[27]	石巨业, 金之钧, 樊太亮, 等. 南图尔盖盆地Aryskum坳陷北部层序发育特征及充填演化模式[J]. 地质科技情报, 2016, 35(6): 70-76, 89.
[28]	冯志强, 李萌, 郭元岭, 等. 中国典型大型走滑断裂及相关盆地成因研究[J]. 地学前缘, 2022, 29(6): 206-223. DOI
[29]	姜仁旗, 吴键, CASTAGNA J, 等. 地球物理技术最新进展: 高分辨率地震频率和相位属性分析技术研究与应用效果[J]. 地学前缘, 2023, 30(1): 199-212. DOI