Characteristics and controlling factors of tuff tight reservoir in Tiaohu formation of Malang sag, Santanghu basin, China

Si, Xueqiang; Wang, Xin; Guo, Huajun; Peng, Bo; Chen, Wei

doi:10.1007/s12517-021-06899-6

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…Malang Tiaohu sag in Santanghu basin, located in the northeast of Xinjiang, is the main battlefield of tight oil exploration and development of the Tuha oilfield . In 2013, tight oil was found for the first time in the second member of the Permian Tiaohu formation in the sag, and good well testing and production test results were obtained. , Further exploration and development practice found that this tight oil reservoir is quite different from the tight oil reservoirs that have been discovered at home and abroad in reservoir lithology, crude oil physical properties, and the source–reservoir configuration relationship. − The details are as follows: (i) the oil reservoir lithology is neither sandstone nor shale and carbonate but sedimentary tuff. (ii) The lithology is pure, no argillaceous, with well-developed pores and high oil saturation.…”

Section: Reservoir Backgroundmentioning

confidence: 96%

The Law and Mechanism of the Sample Size Effect of Imbibition Oil Recovery of Tight Sedimentary Tuff

Yang

Dong

et al. 2022

ACS Omega

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Imbibition is an important mechanism to improve the recovery factor (RF) of a tight oil reservoir. Accurately evaluating the oil production capacity of tight oil reservoirs by imbibition is of great significance for the formulation of oilfield production plans and productivity prediction. However, there is currently no unified regulation on the selection of rock sample size in tight oil reservoir imbibition evaluation experiments, resulting in great differences in reservoir imbibition oil production capacity obtained from rock samples of different sizes, which brings great challenges to the efficient development of tight oil reservoirs. To clarify the law and mechanism of the rock sample size effect of tight core imbibition oil recovery, this paper takes the newly discovered tight sedimentary tuff (TST) oil reservoir as an example. First, several representative real cores were collected. Then, their wettability and pore structure characteristics were analyzed. Finally, physical simulation experiments of imbibition under different rock sample sizes were conducted. The results show that the TST has very favorable imbibition conditions, which are manifested in the following: (i) the wettability is weakly hydrophilic to hydrophilic; (ii) the mineral composition is tuffaceous minerals, calcite, and quartz, without clay minerals; (iii) micro-nanoscale pores are developed; and (iv) the pore throats are evenly distributed. In the imbibition experiments of rock samples of different sizes, the oil production characteristics of the core surface, the variation form of imbibition rate, pore production characteristics, and the influence mode of imbibition pressure on imbibition do not have the sample size effect. However, the RF of the spontaneous imbibition has an obvious sample size effect, and there is a good exponential function relationship between the imbibition RF and the specific surface area (SSA) of cores. The fundamental reason why the rock sample size effect of the TST imbibition oil recovery is relatively stable and has strong regularity is that its pore structure and wettability are relatively homogeneous and stable. The change of rock sample size does not have a great impact on the distribution of the core pore structure and wettability, resulting in no significant change in its imbibition power, resistance, and distance. Therefore, the main factor determining the imbibition RF of rock samples with different sizes is their SSA. The research results of this work can provide an important theoretical basis for understanding the law and mechanism of TST imbibition oil recovery and unifying the imbibition experimental results of small-sized rock samples.

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Section: Reservoir Backgroundmentioning

confidence: 96%

The Law and Mechanism of the Sample Size Effect of Imbibition Oil Recovery of Tight Sedimentary Tuff

Yang

Dong

et al. 2022

ACS Omega

View full text Add to dashboard Cite

show abstract

CT-based 3D pore-fracture network analysis of volcanic reservoirs of Lower Cretaceous Yingcheng formation in southern Songliao Basin, China: Impact on natural gas migration

Bai

et al. 2023

Geoenergy Science and Engineering

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Characteristics and controlling factors of tuff tight reservoir in Tiaohu formation of Malang sag, Santanghu basin, China

Cited by 2 publications

References 8 publications

The Law and Mechanism of the Sample Size Effect of Imbibition Oil Recovery of Tight Sedimentary Tuff

The Law and Mechanism of the Sample Size Effect of Imbibition Oil Recovery of Tight Sedimentary Tuff

CT-based 3D pore-fracture network analysis of volcanic reservoirs of Lower Cretaceous Yingcheng formation in southern Songliao Basin, China: Impact on natural gas migration

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