Distribution regularity and formation mechanism of gas and water in the western area of Sulige gas field, NW China

Dai, Jinyou; Li, Jianting; Wang, Baogang; Pan, Rui

doi:10.1016/s1876-3804(12)60076-7

Cited by 28 publications

(17 citation statements)

References 6 publications

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“…For the fracture-type micromodel, fractures are the main flow channels in the fracture-type micromodel and have a higher flow capacity than pores and cavities. Injection gas preferentially enters the large channels in porous media at the beginning of gas-drive-water process [44]. Therefore, the injection gas rapidly displaces the water in the middle part of fractures (Figure 10b), and then displaces the water in the location of small pores, fracture wrinkles and channel intersections ( Figure Figure 9.…”

Section: Formation Mechanism Of Residual Water In Different Types Of mentioning

confidence: 99%

“…The reservoir space is initially filled with water during the deposition of rocks, and then the original water is displaced by oil or gas during the hydrocarbon migration and accumulation. As a result, the coexistence state of oil-water or gas-water is formed [44]. This displaced and migrated water is called primary movable water.…”

Section: Occurrence States Of Residual Water and Its Effect On Gas Sementioning

confidence: 99%

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Visual Investigation of the Occurrence Characteristics of Multi-Type Formation Water in a Fracture–Cavity Carbonate Gas Reservoir

et al. 2018

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It is difficult to investigate the formation process and occurrence states of water in multi-type reservoirs, due to the strong heterogeneity and complex microstructure of the fracture-cavity carbonate gas reservoirs. To date, there is no systematic study on the occurrence characteristics of multi-type formation water, especially through visual observation experiments. In this paper, a new creation method for visual micromodels based on CT scan images and microelectronic photolithography techniques was described. Subsequently, a gas-drive-water visual experiment was conducted to intuitively study the formation mechanism and the occurrence states of formation water. Then, the ImageJ gray analysis method was utilized to quantitatively investigate the gas-water saturation and the proportion of residual water film. Finally, the occurrence characteristics of formation water and its effects on gas seepage flow were comprehensively analyzed. Visual experimental results showed that: the migration processes of natural gas in different types of reservoirs are different; the water in multiple media consists of native movable water and residual water, and residual water is composed of secondary movable water and irreducible water; the residual water mainly occurs in different locations of different reservoirs with the forms of "water film", "water mass", "water column" and "water droplets"; the main influencing factors are capillary force, surface tension, displacement pressure and channel connectivity. Quantitative results reflect that the saturation of movable water and residual water are the parameters related directly to reservoir physical properties, pore structure and displacement pressure-the smaller the size of flow channel, the larger the space occupied by water film; the thickness proportion of water film is increasing exponentially with the channel size; the thickness proportion of water film decreases as the increase of displacement pressure; the thickness proportion of water film is essentially constant when the displacement pressure increases to a certain extent. The conducted visual investigation not only improves our intuitive understanding of the occurrence characteristics of formation water, but also provides a theoretical basis for the efficient development of fracture-cavity gas reservoirs.

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Section: Formation Mechanism Of Residual Water In Different Types Of mentioning

confidence: 99%

Section: Occurrence States Of Residual Water and Its Effect On Gas Sementioning

confidence: 99%

Visual Investigation of the Occurrence Characteristics of Multi-Type Formation Water in a Fracture–Cavity Carbonate Gas Reservoir

et al. 2018

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“…Affected by heterogeneity, some isolated sand bodies containing water are interrupted or wrapped by non-permeable layers (Dai et al, 2012). Thus, natural gas cannot displace this part of the original water and the isolated water body with high water saturation forms.…”

Section: Lenticular Watermentioning

confidence: 99%

“…Once water appears in the gas well, the permeability of the gas phase of the reservoir will be reduced, and the gas production will drop rapidly, even threatening the production of gas wells (Wang et al, 2013;Heidari Sureshjani et al, 2016). Early thought on the subject holds that the macro distribution of gas-water in the upper Paleozoic of Ordos basin has the trend of the margin of the basin containing water and the middle of the basin containing gas, with water being sporadic produced within the scope of the gas-containing area (Dou et al, 2010;Dai et al, 2012). However, with the increasing degree of exploration within the Zizhou gas field, many wells for testing gas have produced water.…”

Section: Introductionmentioning

confidence: 99%

Study on the Distribution Characteristics of Formation Water in Tight Sandstone Gas Reservoirs of the Shan 23 Member in the Zizhou Gas Field of Ordos Basin

Liu¹,

Zhao²,

Sun³

et al. 2017

TOEFJ

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Abstract:To effectively formulate a scheme for the development of gas reservoirs, the distribution of formation water in the Shan 2 3 member of the Zizhou gas field of the Ordos basin in China was studied in depth, making full use of data covering formation water, logging and production. The study concluded that the types of formation water of the Shan 2 3 member in the Zizhou gas field are edge (bottom) water, lenticular water and formation water residue. The edge (bottom) water in the Shan 2 3 member is mainly distributed in three regions with low structures in the west, south and southeast of the area, respectively, to the well areas of Y47-Y29-Y43, Y64-Y40 and Y69. This layer is generally interpreted as a water layer by well logging and produces a large amount of water discharge in the processes of gas testing and production. The lenticular water in the Shan 2 3 member is mainly scattered in the middle and southern parts of the area and is generally interpreted as a water layer by well logging, mainly in small water bodies. The typical production characteristics of gas wells that produce formation water residue in a gas reservoir are as follows: With less water production, the gas saturation is high, and there is no obvious information about the water layer in the logging curves. However, during production, there is trace formation water, and as production continues, this part of the water is taken out. The edge (bottom) water is distributed in the lower structure of the area and is mainly distributed in the southwest part of the area. It is clearly controlled by the structure, especially the low-amplitude structure; thus, structure is more important for the control of edge (bottom) water. Structural characteristics have some influence on the lenticular water and the formation water residue in gas reservoirs. The position of the lower structure is the main area that enriches water. In a relatively independent region containing gas, the position of the lower micro structure is also a common distribution area of water. In addition, a larger water body often forms at the pinchout and the bend of a sand body.

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“…For a certain gas reservoir, Sw0 is determined by core analysis, and P0 is obtained through the two curves; Sw1 is from the relative permeability curve, and P1 is obtained through the two curves; P2 is the practical drawdown pressure from the performance data, and Sw2 is obtained through the two curves. Taking Western Sulige gas field for example [5][6], analysis is as follows: Fig.1 The schematic diagram of immobile water, movable water and free water Firstly, the Sw0 is determined from the statistical analysis of the water saturation of 8970 pieces of core in 90 wells of Western Sulige gas field (Fig. 2.…”

Section: The Determination Of Dynamic Irreducible Water Saturationmentioning

confidence: 99%

Dynamic irreducible water saturation and its determination method

Dai¹,

Wang²,

Kong³

et al. 2016

Proceedings of the 3rd International Conference on Material Engineering and Application (ICMEA 2016)

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The irreducible water saturation, the saturation of water when it begins to flow, is not a fixed value in the development process, whose numerical value is related to specific reservoir production conditions. Based on the integration of relative permeability curve and mercury intrusion curve, the author studies the change regularity of the irreducible water saturation under different production conditions (drawdown pressure), and puts forward the concept of dynamic irreducible water saturation and its determination method. Taking west Sulige gas field for application example, the actual drawdown pressure is 13.7 MPa and its dynamic irreducible water saturation is 30%. However, the conventional irreducible water saturation is 38%, which is getting from relative permeability curve. By analyzing the differences between two kinds of irreducible water saturation, the author thinks that the dynamic irreducible water saturation is closer to the actual production condition and it can be used in the correction of relative permeability curve and the study of lower limit of reservoir physical property.

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Distribution regularity and formation mechanism of gas and water in the western area of Sulige gas field, NW China

Cited by 28 publications

References 6 publications

Visual Investigation of the Occurrence Characteristics of Multi-Type Formation Water in a Fracture–Cavity Carbonate Gas Reservoir

Visual Investigation of the Occurrence Characteristics of Multi-Type Formation Water in a Fracture–Cavity Carbonate Gas Reservoir

Study on the Distribution Characteristics of Formation Water in Tight Sandstone Gas Reservoirs of the Shan 23 Member in the Zizhou Gas Field of Ordos Basin

Dynamic irreducible water saturation and its determination method

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