The characteristics of low permeability reservoirs, gas origin, generation and charge in the central and western Xihu depression, East China Sea Basin

Su, Ao; Chen, Honghan; Chen, Xu; Cong, He; Liu, Hongping; Li, Qian; Wang, Cunwu

doi:10.1016/j.jngse.2018.01.034

Cited by 43 publications

(22 citation statements)

References 26 publications

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“…The specific operation steps are as follows. (1) The aging cores (#2 and #3) were inserted into the primary waterflooding experimental group, respectively, and the oil displacement rate was set at 0.2 mL/min. The injection time was 4 to 5 h and until the oil production became negligible.…”

Section: Core Displacement Tests To Evaluate the Eormentioning

confidence: 99%

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Controlling the Hydro-Swelling of Smectite Clay Minerals by Fe(III) Reducing Bacteria for Enhanced Oil Recovery from Low-Permeability Reservoirs

Cui

Wang

et al. 2022

Energies

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The hydro-swelling of smectite clay minerals in low-permeability reservoirs further decreases the reservoir permeability and results in low oil recovery. Currently, the traditional chemical anti-swelling agents are widely used, but most of them are only effective in the short term and are not environmentally friendly. Here, we report the use of Fe(III) reducing microorganisms (FeRM) as a novel green anti-swelling agent to enhance oil recovery from low-permeability reservoirs. The results showed that FeRM (Proteus hauserifective) inhibited/reduced the hydro-swelling of smectite clay minerals through a three-step biochemical mineralization reaction process. The structural Fe(III) reduction in minerals by FeRM can be an important driving force for illitization. The maximum inhibition efficiency (36.6%) and shrinkage efficiency (69.3%) were achieved at 35 °C and 0.1 Mpa. Furthermore, core displacement tests showed that FeRM reduced the waterflooding injection pressure by 61.1%, increased the core permeability by 49.6%, and increased the oil recovery by 8.1%. Finally, the mechanism of FeRM-enhanced oil recovery was revealed. This study demonstrates that using FeRM to inhibit/reduce the hydro-swelling of clay minerals holds great potential to enhance the oil recovery from low-permeability reservoirs.

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Section: Core Displacement Tests To Evaluate the Eormentioning

confidence: 99%

“…With the depletion of high-quality oil reservoirs worldwide, the demand for oil production from low-permeability reservoirs is ever-increasing [1,2]. Petroleum production from lowpermeability reservoirs is a huge challenge because conventional recovery techniques are inefficient [3].…”

Section: Introductionmentioning

confidence: 99%

Controlling the Hydro-Swelling of Smectite Clay Minerals by Fe(III) Reducing Bacteria for Enhanced Oil Recovery from Low-Permeability Reservoirs

Cui

Wang

et al. 2022

Energies

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“…In recent years, the increasing intensity of research and development pertaining to oil and gas exploration has revealed the crucial role played by the relevant coal-measure source rock in the formation of oil and gas resources in this area [1][2][3][4][5]. The Xihu Sag is located northeast of the ECSS, and the source rocks are primarily developed in the Pinghu, Huagang, and Longjing formations [1,6]. In particular, the coal rock of the Pinghu Formation is the primary source rock in the Xihu Sag and is characterized by its large thickness and wide distribution [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Evidence from the Changing Carbon Isotopic of Kerogen, Oil, and Gas during Hydrous Pyrolysis from Pinghu Formation, the Xihu Sag, East China Sea Basin

Cao

et al. 2021

Energies

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Semi-open hydrous pyrolysis experiments on coal-measure source rocks in the Xihu Sag were conducted to investigate the carbon isotope evolution of kerogen, bitumen, generated expelled oil, and gases with increasing thermal maturity. Seven corresponding experiments were conducted at 335 °C, 360 °C, 400 °C, 455 °C, 480 °C, 525 °C, and 575 °C, while other experimental factors, such as the heating time and rate, lithostatic and hydrodynamic pressures, and columnar original samples were kept the same. The results show that the simulated temperatures were positive for the measured vitrinite reflectance (Ro), with a correlation coefficient (R2) of 0.9861. With increasing temperatures, lower maturity, maturity, higher maturity, and post-maturity stages occurred at simulated temperatures (Ts) of 335–360 °C, 360–400 °C, 400–480 °C, and 480–575 °C, respectively. The increasing gas hydrocarbons with increasing temperature reflected the higher gas potential. Moreover, the carbon isotopes of kerogen, bitumen, expelled oil, and gases were associated with increased temperatures; among gases, methane was the most sensitive to maturity. Ignoring the intermediate reaction process, the thermal evolution process can be summarized as kerogen0(original) + bitumen0(original)→kerogenr (residual kerogen) + expelled oil (generated) + bitumenn+r (generated + residual) + C2+(generated + residual) + CH4(generated). Among these, bitumen, expelled oil, and C2-5 acted as reactants and products, whereas kerogen and methane were the reactants and products, respectively. Furthermore, the order of the carbon isotopes during the thermal evolution process was identified as: δ13C1 < 13C2-5 < δ13Cexpelled oil < δ13Cbitumen < δ13Ckerogen. Thus, the reaction and production mechanisms of carbon isotopes can be obtained based on their changing degree and yields in kerogen, bitumen, expelled oil, and gases. Furthermore, combining the analysis of the geochemical characteristics of the Pinghu Formation coal–oil-type gas in actual strata with these pyrolysis experiments, it was identified that this area also had substantial development potential. Therefore, this study provides theoretical support and guidance for the formation mechanism and exploration of oil and gas based on changing carbon isotopes.

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“…Recent oil and gas discoveries showed that lithology and structure-lithologic reservoirs are new directions for further exploration breakthroughs in this basin . In recent years, increasing attention has been paid to the study of Paleocene tight sandstone reservoirs in the East China Sea Shelf Basin, and fruitful studies have been carried out on the genesis and reservoir distribution prediction of the tight sandstone reservoirs in the East China Sea Shelf Basin from the perspectives of deposition, diagenesis, and accumulation. − However, the pore structure of tight sandstone remains to be further studied. Lishui Sag, located in the south of the East China Sea Shelf Basin, has been the site of productive comprehensive research and exploration of petroleum geology in the past 10 years and is an important oil and gas strategic area for the development of unconventional tight sandstone reservoirs in the basin. , The study of the characteristics of tight sandstone reservoirs in Lishui Sag will provide an important reference for the study on the characteristics of tight sandstone reservoirs in the East China Sea Shelf Basin and even the whole western Pacific region.…”

Section: Introductionmentioning

confidence: 99%

Pore-Throat Size Distribution and Classification of the Paleogene Tight Sandstone in Lishui Sag, East China Sea Shelf Basin, China

Zhao

Ma³

2020

Energy Fuels

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The characteristics of tight sandstone reservoirs are closely influenced by the complex pore structure and the widths of pore-throat size distributions (P-TSDs). Because of the limitations of various techniques, it is difficult to characterize the morphology and size distribution jointly of the pore-throat structure. In this study, thin section, scanning electron microscopy, X-ray fluorescence diffraction, high-pressure mercury injection, and constant speed mercury injection were combined to analyze the pore throat structure characteristics of the Lishui tight sandstone reservoir in the southern East China Sea Shelf Basin, and joint characterization of morphology and size distribution of the pore-throat structure was established based on X-ray computed tomography (XCT) analysis. The results showed that the Paleocene tight sandstone in Lishui Sag generally has a high content of lithic and feldspar, which provides a good material basis for the development of clay minerals in the reservoir. Autogenic illite and kaolinite occupy the majority of pore-throat space in tight sandstone reservoirs and form intergranular micropores of clay minerals with a radius less than 1 μm, which are important factors for the development of micropores and throats in tight sandstone. XCT scanning showed that as the content of clay mineral increased, the number of throats developed per unit volume decreased, the isolated point-like micropores significantly increased, and the connectivity between micropores deteriorated. Based on the pore and throat information obtained by XCT scanning, the pore and throat radius frequency and volume distribution curves were generated. According to the distribution characteristics of the curves, the pore size distribution types of tight sandstone are divided into two types: peak type and flat type, and throat size distribution types are divided into three types: right peak type, left peak type, and bimodal type.

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The characteristics of low permeability reservoirs, gas origin, generation and charge in the central and western Xihu depression, East China Sea Basin

Cited by 43 publications

References 26 publications

Controlling the Hydro-Swelling of Smectite Clay Minerals by Fe(III) Reducing Bacteria for Enhanced Oil Recovery from Low-Permeability Reservoirs

Controlling the Hydro-Swelling of Smectite Clay Minerals by Fe(III) Reducing Bacteria for Enhanced Oil Recovery from Low-Permeability Reservoirs

Evidence from the Changing Carbon Isotopic of Kerogen, Oil, and Gas during Hydrous Pyrolysis from Pinghu Formation, the Xihu Sag, East China Sea Basin

Pore-Throat Size Distribution and Classification of the Paleogene Tight Sandstone in Lishui Sag, East China Sea Shelf Basin, China

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