Development potential and technical strategy of continental shale oil in China

Hu, Suyun; Zhao, Wenzhi; Hou, Lianhua; Zhi, Yang; Zhu, Rixiang; Wu, Songtao; Bai, Baojun; Xu, Jin

doi:10.1016/s1876-3804(20)60103-3

Cited by 183 publications

(81 citation statements)

References 15 publications

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“…Shale oil is a kind of unconventional oil resources with great potential. It has large reserves and wide distribution in the world, which may become an important substitute for conventional oil in the future [1,2]. The United States has changed from an oil-importing country to an oil-exporting country benefit from the successful commercial exploration and production of marine-sourced shale oil, which has aroused great attention to shale oil in the world [3,4].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Hydration Damage and Its Influence on Permeability of Lamellar Shale Oil Reservoirs in Ordos Basin

et al. 2021

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The continental shale oil reservoir has low permeability, high clay content, rich lamellar structure, and strong heterogeneity, which makes the reservoir vulnerable to hydration damage. In order to study characteristics of hydration damage and its influence on permeability of lamellar shale oil reservoirs, a series of experiments such as high-pressure mercury injection, steady gas permeability, rock thin section identification, and scanning electron microscope were carried out with the downhole core in Ordos Basin as the experimental object. The effects of water and water-based drilling fluid on pore size distribution, permeability, and rock microstructure were analyzed. Results show that the pore size of the reservoir is mainly nanoscale, and the pore size of shale changes most dramatically in the stage of hydration for 12-24 hours, while that of tuff changes most dramatically in 24-48 hours. The permeability increases rapidly with hydration time and then tends to be stable, among which the permeability of samples with lamellar structure in the direction parallel to the lamellar structure is most easily affected by hydration and changes fastest. Hydration leads to the formation of new pores, new fractures, and the expansion of existing fractures in rocks, especially in the strata containing large amounts of terrigenous clastic, lamellar structure, and pyrite. The new seepage channel increases the permeability of rock, and the soil powder and plugging particles in drilling fluid are easy to form protective mud cake in these places. These protective mud cakes not only change the microstructure of rock but also inhibit the influence of hydration on the pore space and permeability of rock, which play an effective role in preventing the mineral shedding on the rock surface, reducing the increase of micropores and delaying hydration.

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Section: Introductionmentioning

confidence: 99%

Characteristics of Hydration Damage and Its Influence on Permeability of Lamellar Shale Oil Reservoirs in Ordos Basin

et al. 2021

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“…Shale oil has drawn a great deal of attention in terms of the global exploration and production of unconventional oil and gas (Goodarzi, 2020;Kim and Shin, 2020;Solarin, 2020;Kara and Isik, 2021). China's terrestrial shale oil has a huge resource potential, and breakthroughs have been achieved in the Permian Lucaogou Formation in the Jimsar Sag, Junggar Basin, as well as in the Chang 7 Member in the Ordos Basin (Hou et al, 2020a(Hou et al, ,b, 2021Hu et al, 2020;Ma et al, 2020;Zhao et al, 2020). However, the shale oil is only in its initial stage and is under geological conditions that are dramatically different from those of the marine shale oil in North America.…”

Section: Introductionmentioning

confidence: 99%

Experimental Methods for the Quantitative Assessment of the Volume Fraction of Movable Shale Oil: A Case Study in the Jimsar Sag, Junggar Basin, China

Zhao

Hou

et al. 2021

Front. Earth Sci.

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Deep insights into the movability of the retained shale oil are of great significance to shale oil. Rock and crude oil samples were collected from well J174 in the Jimsar Sag, Junggar Basin. Rock samples were subjected to different extraction followed by analysis of the component in the extracts, and measurement of porosity in conjunction with nuclear magnetic resonance and high-pressure mercury injection analysis. The results of these analyses were used to establish an experimental method for quantitative assessment of movable shale oil. The extract content of the component varied among different extraction and between mud shale and non-mud shale samples. The saturated hydrocarbon in the extracts of the mud shale was similar to those of the non-mud shale after extraction with CHCl3 alone or after sequential extraction with nC6 + CHCl3. The aromatic hydrocarbon in the extract were significantly lower for the mud shale than for the non-mud shale after extraction with nC6, but the opposite was observed after sequential extraction with nC6 + CHCl3. The contents of the non-hydrocarbon in the extract were significantly lower for the mud shale than for the non-mud shale after extraction with nC6, but the opposite was observed after extraction with CHCl3 or nC6 + CHCl3. The contents of the asphaltene in the extract were not significantly different for the mud shale and non-mud shale after extraction with nC6, but the contents were higher for the mud shale than for the non-mud shale after extraction with nC6 + CHCl3 or CHCl3. The viscosity of the crude oil was negatively correlated with the saturated hydrocarbon, was positively correlated with the aromatic hydrocarbon and non-hydrocarbon, and was not correlated with the asphaltene. For the mud shale and non-mud shale, their porosity after extraction with nC6 or CHCl3 was higher than their original porosity. Moreover, their porosity after extraction with CHCl3 was higher than after extraction with nC6. The movable oil was significantly correlated with the lithology, with sandstone allowing for a higher fluid movability than mud shale and dolomite allowing for a higher fluid movability than siliceous rocks.

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“…Shale oil production in the United States is expected to start to decline after 2031, and it will drop to 1.15 million tons per day by 2050 [9,10]. At present, the exploration and development of shale oil in China have made important progress and are gradually moving towards commercial development [9,11]. In recent years, China Geological Survey, CNPC, SINOPEC, and Yanchang Oilfield have increased their exploration and development efforts of shale oil, which have made important discoveries and breakthroughs in multiple series of strata in different basins.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, China Geological Survey, CNPC, SINOPEC, and Yanchang Oilfield have increased their exploration and development efforts of shale oil, which have made important discoveries and breakthroughs in multiple series of strata in different basins. Industrial oil flow of shale oil has been obtained in many places, including the Cangdong Sag of the Dagang Oilfield in the Bohai Bay Basin and the Jimsar Sag of the Junggar Basin, and construction of shale oil fields has been started [9][10][11][12]. Among them, in 2007, the shale oil and gas field began to be paid attention to in Shengli Oilfield of SINOPEC.…”

Section: Introductionmentioning

confidence: 99%

“…Among them, in 2007, the shale oil and gas field began to be paid attention to in Shengli Oilfield of SINOPEC. And in 2011, the first special exploration well for shale oil, well Boyeping1, was deployed [11]. As of the end of 2018, Shengli Oilfield has conducted tests of the section of 68 wells where mud and shale have been developed in the Jiyang Depression.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Evaluation on the Conductivity of Branch Fracture with Low Sand Laying Concentration and Its Influencing Factors in Shale Oil Reservoirs

et al. 2021

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The productivity of shale oil reservoirs is mainly determined by the hydraulic fractured reservoir volume. The branch fractures with low sand laying concentration are the main channels connecting the shale matrix and the main fractures. Maintaining the branch fracture conductivity is significant to the production of shale oil. In this study, a series of shale branch fracture conductivity and soaking experiments were conducted using a core flooding device and a small reactor, and the influences of different factors on the fracture conductivity were evaluated. The results show that when the sand laying concentration in fractures is less than 3 kg/m2, the branch fractures present a significant stress sensitivity. Particularly when the sand laying concentration is less than 1 kg/m2, and the closure pressure is greater than 15 MPa, there will be a risk of proppant embedded and fracture closed. The antiswelling agent has an inhibitory effect on the shale swelling. When the concentration of the antiswelling agent in the gel-breaking fluid is 2%, the swelling factor of shale powder is only 1.84%. Comparatively, the 0.5% of the antiswelling agent has a poor effect which can cause the shale rock to crack when the effective stress decreases. It can cause the fracture conductivity to decline by 70-90% when the gel-breaking fluid flows back associated with the shale oil. The probability of core breaking and proppant embedding will increase. The frequent shut-in and rapid open-flow for production can accelerate the damage of fracture conductivity. It is necessary to optimize the fracturing fluid and the open flow scheme to prevent the rapid decline of production in shale oil reservoirs.

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Development potential and technical strategy of continental shale oil in China

Cited by 183 publications

References 15 publications

Characteristics of Hydration Damage and Its Influence on Permeability of Lamellar Shale Oil Reservoirs in Ordos Basin

Characteristics of Hydration Damage and Its Influence on Permeability of Lamellar Shale Oil Reservoirs in Ordos Basin

Experimental Methods for the Quantitative Assessment of the Volume Fraction of Movable Shale Oil: A Case Study in the Jimsar Sag, Junggar Basin, China

Experimental Evaluation on the Conductivity of Branch Fracture with Low Sand Laying Concentration and Its Influencing Factors in Shale Oil Reservoirs

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