Shale gas effective fracture network volume prediction and analysis based on flow back data: A case study of southern Sichuan Basin shale

Ren, Lan; Wang, Zhenhua; Zhao, Jinzhou; Lin, Ran; Wu, Jianfa; Song, Yi; Tang, Dengji

doi:10.1016/j.geoen.2023.211963

Cited by 4 publications

(6 citation statements)

References 14 publications

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“…where V fi is initial volume of effective fracture, m 3 ; and V 0 is initial fracture volume, m 3 . It can be seen from Figure 1 that the longitudinal equivalent fracture half-length is…”

Section: Calculation Of Fracture Network Volumementioning

confidence: 99%

“…where B wi is the fracturing fluid volume coefficient under original pressure, dimensionless; W p is current cumulative fracturing fluid volume of flow back m 3 ; and W res is the remaining fracturing fluid volume, m 3 . The remaining fracturing fluid volume W res is inputted into the above formula:…”

Section: (B) Intrusion Of Matrix Gasmentioning

confidence: 99%

“…The matrix pressure P m (k + 1) is calculated in combination with the matrix material balance Equation (62), and then G mf is calculated by using Equation (34), which is then brought into the Equation (49), and P f (k + 1) is solved by the dichotomy method. (4) The P f (k + 1) and P m (k + 1) are assigned to P f (k) and P m (k), and steps (1), (2), and (3) are repeated until k = Num.…”

Section: Model Solutionmentioning

confidence: 99%

“…where P fi is initial fracture network pressure, MPa; P wf is bottom hole flow pressure, MPa; q w is water production rate, m 3 /h; t MB is equivalent time, h; and W p is cumulative water production, m 3 . The established shale gas fracturing two-phase flow back model was used to calculate the flow back data of 1000 h. The model parameter settings are shown in Table 2.…”

Section: Flow Back Model Validationmentioning

confidence: 99%

“…It is of great significance to the evaluation of fracturing effect and productivity prediction. Effective fracture network volume information can be obtained by accurately interpreting flow back data [3]. It is of great significance to the evaluation of fracturing effect and productivity prediction.…”

Section: Introductionmentioning

confidence: 99%

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The Inversion Method of Shale Gas Effective Fracture Network Volume Based on Flow Back Data—A Case Study of Southern Sichuan Basin Shale

Tang,

Wu,

Zhao

et al. 2024

Processes

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Fracture network fracturing is pivotal for achieving the economical and efficient development of shale gas, with the connectivity among fracture networks playing a crucial role in reservoir stimulation effectiveness. However, flow back data that reflect fracture network connectivity information are often ignored, resulting in an inaccurate prediction of the effective fracture network volume (EFNV). The accurate calculation of the EFNV has become a key and difficult issue in the field of shale fracturing. For this reason, the accurate shale gas effective fracture network volume inversion method needs to be improved. Based on the flow back characteristics of fracturing fluids, a tree-shaped fractal fracture flow back mathematical model for inversion of EFNV was established and combined with fractal theory. A genetic algorithm workflow suitable for EFNV inversion of shale gas was constructed based on the flow back data after fracturing, and the fracture wells in southern Sichuan were used as an example to carry out the EFNV inversion. The reliability of the inversion model was verified by testing production, cumulative gas production, and microseismic results. The field application showed that the inversion method proposed in this paper can obtain tree-shaped fractal fracture network structure parameters, fracture system original pressure, matrix gas breakthrough pressure, fracture compressibility coefficient, reverse imbibition index, equivalent main fracture half length, and effective initial fracture volume (EIFV). The calculated results of the model belong to the same order of magnitude as those of the HD model and Alkouh model, and the model has stronger applicability. This research has important theoretical guiding significance and field application value for improving the accuracy of the EFNV calculation.

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“…where V fi is initial volume of effective fracture, m 3 ; and V 0 is initial fracture volume, m 3 . It can be seen from Figure 1 that the longitudinal equivalent fracture half-length is…”

Section: Calculation Of Fracture Network Volumementioning

confidence: 99%

Section: (B) Intrusion Of Matrix Gasmentioning

confidence: 99%

Section: Model Solutionmentioning

confidence: 99%

Section: Flow Back Model Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Inversion Method of Shale Gas Effective Fracture Network Volume Based on Flow Back Data—A Case Study of Southern Sichuan Basin Shale

Tang,

Wu,

Zhao

et al. 2024

Processes

Self Cite

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Characterizing rock transverse anisotropic spatial variations using digital drilling

Wu,

He,

Yuan

et al. 2024

Geoenergy Science and Engineering

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Research on the Influence of Natural Fracture Development on the Deep Shale Gas Well Fracture Network Construction in Southern Sichuan

Peng,

Zhao,

Ren

et al. 2024

SPE Annual Technical Conference and Exhibition

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The Sichuan Basin, China's largest shale gas development region, encompasses the natural fracture-rich Luzhou Block. The high-density non-uniform natural fractures in this area significantly influence the construction quality and efficiency of deep shale gas horizontal wells. Research indicates that the mechanical properties and spatial distribution of these natural fractures affect the propagation and diversion of hydraulic fractures, but the governing laws remain to be fully elucidated. This study categorizes the Luzhou Block's naturally fractured areas into six types based on their development characteristics and relative positions to horizontal well sections. Furthermore, it introduces a method for morphological inversion of shale gas well fracture networks using microseismic monitoring data. This method was applied to 24 deep shale gas wells in the Block and combined with the six types of naturally fractured areas, the above underlying influence mechanism was derived. Then it reveals how naturally fractured areas with different characteristics influence the fracture network morphology and complexity and analyzes the relationship between fracture network quality and well production. The results demonstrate that during the hydraulic fracturing process in deep shale gas reservoirs, the development areas of natural fractures can capture or intercept the fracture network, obstructing its expansion behavior, reducing its area and complexity, and ultimately leading to a decrease in gas well production. In particular, when a small-angle, large-scale naturally fractured area develops near the wellbore, the hydraulic fractures will quickly propagate to this area. After activating and communicating the natural fractures, it may cause rapid fluid filtration and a sharp drop in the net pressure within the fractures, severely impacting stimulation performance. It suggests that adjusting construction parameters appropriately may mitigate the adverse impact of natural fractures on the fracturing effect. These findings clarify how naturally fractured areas with different development characteristics affect stimulation performance and offer insights and references for designing and optimizing deep shale gas well fracturing technology.

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Shale gas effective fracture network volume prediction and analysis based on flow back data: A case study of southern Sichuan Basin shale

Cited by 4 publications

References 14 publications

The Inversion Method of Shale Gas Effective Fracture Network Volume Based on Flow Back Data—A Case Study of Southern Sichuan Basin Shale

The Inversion Method of Shale Gas Effective Fracture Network Volume Based on Flow Back Data—A Case Study of Southern Sichuan Basin Shale

Characterizing rock transverse anisotropic spatial variations using digital drilling

Research on the Influence of Natural Fracture Development on the Deep Shale Gas Well Fracture Network Construction in Southern Sichuan

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