Formation and distribution of tuffaceous tight reservoirs in the Permian Tiaohu Formation in the Malang sag, Santanghu Basin, NW China

Ma, Jian; Huang, Zhilong; Shijun, Liang; Liang, Hao; Xue, Dongqing; Chen, Xuan; Fan, Tanguang

doi:10.1016/s1876-3804(16)30093-3

Cited by 18 publications

(3 citation statements)

References 7 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. 50 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. 51,52 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.…”

Section: Reservoir Backgroundmentioning

confidence: 97%

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: 97%

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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“…The greater vitric concentration is the result of comparatively low-temperature eruptive activity (Ma et al, 2016;Aulia and Setiawan, 2019). Qvsb 1 contain major minerals such as Feldspar, Amphibole, Pyroxene, and Plagioclase.…”

Section: Volcanic Geology and Aquifer Characteristicsmentioning

confidence: 99%

Geological and Morphometric Characteristics of Quaternary Pyroclastic Aquifers in Salak and Pangrango Stratovolcano.

Nugraha

Ghozi

Fadillah³

et al. 2023

J. Geoscience Eng. Environ. Technol.

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Indonesia is located in a subduction zone formed by the collision of continental and oceanic plates. Many volcanoes form as a result of these conditions along the arc. Springs on the volcano's slopes are widely used for domestic, irrigation, and industry water use. Investigating the characteristics of aquifers and springs is essential to ensure groundwater sustainability by providing a robust geological framework. Meanwhile, groundwater in a volcanic geological setting has good quality characteristics because of its occurrence process, which interacts with many minerals in pyroclastic rocks that act as aquifers. The study area is located in the Lido Catchment Area (LCA), which is situated between two distinct volcanic slopes. Geological and morphometric analysis at LCA is the basis of important information relating to its hydrogeological systems. The analysis of thin rock sections and parameters of the physical properties of water in groundwater springs supports our research. We applied a comprehensive geological and morphometric analysis to obtain detailed information about the aquifer. This study aimed to determine the characteristics of aquifers in pyroclastic rocks and their relationship to the formation of springs. From the research conducted, the characteristic of water can be distinguished based on the geological conditions of its constituents. There are 6 different lithological characteristics in the study area: polymictic breccia, monomictic breccia, lapilli, lapilli tuff, coarse tuff, and fine tuff. From the lithology variations obtained, breccia, lapilli, and coarse tuff can play a good role as aquifers. Geological correlations and groundwater systems in the study area show groups of superficial, mixed, and alteration springs. The system of water flows in aquifers through inter-grains or rock fractures. The types of springs in LCA are dominated by depression and fracture types. These results are fundamental information for understanding hydrogeological systems in future volcanic geological settings.

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“…With the continuous depletion of conventional oil and gas resources and the huge demand for oil and gas resources due to rapid economic development, the exploration and development of unconventional oil and gas resources have become more and more important. − In recent years, the Tuha oilfield has conducted a lot of geological exploration and oil and gas testing in the Santanghu Basin in northeastern Xinjiang, China, and finally discovered a new type of tight oil reservoirs, called tight sedimentary tuff reservoirs (TSTRs). − The formation of TSTRs is closely related to volcanic eruption and lake-basin deposition of volcanic ash. The exploration and development results show that TSTRs are significantly different from conventional tight oil reservoirs in terms of the reservoir-forming model, lithology, physical properties, and fluid properties. − …”

Section: Introductionmentioning

confidence: 99%

Study on Influencing Factors of Water Huff-n-Puff Oil Recovery in Matrix-Fracture Systems of the Tight Sedimentary Tuff Reservoirs

Yang

Jin

et al. 2022

ACS Omega

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Tight sedimentary tuff reservoirs (TSTRs) are a new type of tight oil reservoirs, which are mainly developed by water huff-n-puff (WHP). However, there is no quantitative study on the effect of water injection pressure (WIP) and fracture density (FD) on the oil recovery effect of WHP, and the reasons for the low flow-back rate (FR) of the injected water are also not fully explained. In this study, the real cores of TSTRs were used to simulate the seepage state of the matrix-fracture systems of the reservoir, the effects of WIP and FD on the WHP were quantitatively studied, and the reasons for the low FR of the injected water were comprehensively analyzed. The result shows that in five cycles of WHP, the recovery factor (RF) of the core only increases from 8.72 to 10.91% with the WIP increasing from 25 to 30 MPa. However, when the WIP is 40 MPa (rock breakdown pressure), the RF of the core reaches 16.47%, indicating that overfracture-pressure water injection has an obvious improvement effect on the oil recovery effect of WHP in TSTRs. Increasing the FD can also significantly improve the RF and oil recovery efficiency (ORE) of WHP in TSTRs. When the FD of the core increases from 0.34 to 0.44 cm –1 , the RF of five cycles of WHP increases by 9.26%, the ORE increases by 8.61%, and the FR of the injected water decreases by 0.56%. The reasons for the low FR of the injected water in WHP in tight oil reservoirs are matrix water locking, fracture water locking, and reservoir nonconstant-volume water locking. The study can provide an important reference for the efficient development of the WHP in TSTRs.

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Formation and distribution of tuffaceous tight reservoirs in the Permian Tiaohu Formation in the Malang sag, Santanghu Basin, NW China

Cited by 18 publications

References 7 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

Geological and Morphometric Characteristics of Quaternary Pyroclastic Aquifers in Salak and Pangrango Stratovolcano.

Study on Influencing Factors of Water Huff-n-Puff Oil Recovery in Matrix-Fracture Systems of the Tight Sedimentary Tuff Reservoirs

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