A new model to evaluate two leak points in a gas pipeline

Rui, Zhenhua; Han, Guoqing; Zhang, He; Wang, Sai; Pu, Hui; Ling, Kegang

doi:10.1016/j.jngse.2017.08.025

Cited by 103 publications

(24 citation statements)

References 11 publications

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“…The target reservoir locates in the piedmont region of Tarim Basin, which is characteristic of desert environment, great reservoir depth (over 3000 m), and high reservoir temperature (approximately 140 ∘ C) [38][39][40]. To hydraulically fracture this reservoir, cross-linked guar was used as the fracturing fluid.…”

Section: Flowback Fluidmentioning

confidence: 99%

Study on Fluid-Rock Interaction and Reuse of Flowback Fluid for Gel Fracturing in Desert Area

et al. 2018

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Hydraulic fracturing requires a large volume of fresh water, which is difficult and expensive to obtain in the desert area such as Tarim Basin. Currently, flowback fluid is typically transported to the sewage treatment plant and then discharged after reaching environmental requirements; however, this is not only costly, but also a waste of water resource. Therefore, it is imperative to understand the potential interactions between fracturing fluid and reservoir rock, and then find solutions to reuse the flowback water for subsequent fracturing. In this study, once flowback fluid was directly collected from the field, its chemical compositions were analyzed; then, filtering, decoloring, and chelating methods were chosen to effectively remove or shield the unfavorable reintroduced components. Moreover, pH value was further tuned during different stages of the recycling process to ensure good gelation and cross-linking properties of guar. Cross-linked guar synthesized with the flowback fluid was evaluated in the lab through shear resistance tests and coreflood tests under the reservoir conditions; results indicated the recycled gel behaved similarly as the original gel, or even better. From this work, a cheap and effective treatment process was proposed to reuse the flowback fluid in the desert area.

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Section: Flowback Fluidmentioning

confidence: 99%

Study on Fluid-Rock Interaction and Reuse of Flowback Fluid for Gel Fracturing in Desert Area

et al. 2018

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“…Coal seams are often characterized by extremely low permeability and a unique natural fracture network system consisting of cleats. Hydraulic fracturing is a widely applied measure that can create HFs and improve the connectivity of natural fractures (NFs) in coal seams [1][2][3][4][5][6]. However, during production, CBM wells tend to be deficient due to decreasing fracture conductivity, which results in declining productivity.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Propagation Behavior of Hydraulic Fractures in Coal Seam during Refracturing

Xun

Zhang

et al. 2019

Geofluids

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Refracturing is an effective technology for reinstituting a percolation path and improving the fracture conductivity in coal measure strata. Hydraulic fracture (HF) propagation is complicated due to the presence of cleats and stress change caused by pore pressure changes. Many scholars have studied HF propagation in the initial fracturing of coal, but the refracturing in coal seams is rarely mentioned. In this study, laboratory refracturing experiments were conducted on large natural coal specimens under various triaxial stress states to investigate the propagation of HFs in coal seams. The mechanical properties of coal were tested before refracturing. The maximum and the minimum horizontal principal stresses are inverted to simulate the stress change caused by the production and pore pressure reduction of the stress condition after initial fracturing. Experimental results showed three different types of HF initiation and propagation during refracturing: (1) under low horizontal stress differences (0-2 MPa), HF propagated along the cleats, and no new HFs were formed on the walls of the initial HFs regardless of changes in the horizontal stress; (2) under high horizontal stress differences (4–8 MPa) with no stress inversion, a major HF was initiated parallel to the orientation of maximum horizontal stress during initial fracturing; new branches propagated along cleats in the orientation of the minimum horizontal stress during refracturing; and (3) under high horizontal stress differences (4–8 MPa) with maximum and minimum horizontal stress inversions, the main HF formed along the orientation of the maximum horizontal stress, and a new HF perpendicular to the initial HF was formed during refracturing. Multiple factors affect fracture morphology during refracturing. Cleats affect the HF growth path and the creation of new branches. The in situ stress determines the initiation and propagation of new HFs.

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“…With the increasingly lack of energy sources and strict requirement of customers, more attention is being paid on unconventional resources by researchers and scholars [1][2][3][4][5][6][7]. Among these reserves, tight oil reservoirs have larger proportion.…”

Section: Introductionmentioning

confidence: 99%

A Semianalytical Approach for Production of Oil from Bottom Water Drive Tight Oil Reservoirs with Complex Hydraulic Fractures

Dai

Chun-qiang²,

Wang

et al. 2019

Journal of Chemistry

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In order to improve the recovery rate, fractured horizontal wells are widely used in tight reservoirs. In general, a complex fracture system is generated in tight reservoirs to improve oil production. Based on the fractal theory, a semianalytical model is presented to simulate a complex fracture system by using the volumetric source method and superposition principle, and the solutions are determined iteratively. The reliability of this model is validated through numerical simulation (Eclipse 2011); it shows that the result from this method is identical with that from the numerical simulation. The study on influence factors of this model was focused on matrix permeability, fractal dimension, and half-length of main fracture. The results show that (1) the production increases with the increase of half-length of main fracture and matrix permeability during the initial production stage, but the production difference becomes smaller in different half-length of main fractures and matrix permeability in middle and later stages and (2) the cumulative production increases with the increase of fractal dimension, and the increments of cumulative production in different fractal dimensions gradually increase during the initial production stage, but the increments tend to be stable in middle and later stages. This study can be used for forecasting the oil production from bottom water tight oil reservoirs with complex hydraulic fractures. It can also guide in optimization of horizontal well fracturing design to improve oil production and oil recovery in bottom water tight oil reservoirs.

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A new model to evaluate two leak points in a gas pipeline

Cited by 103 publications

References 11 publications

Study on Fluid-Rock Interaction and Reuse of Flowback Fluid for Gel Fracturing in Desert Area

Study on Fluid-Rock Interaction and Reuse of Flowback Fluid for Gel Fracturing in Desert Area

Experimental Investigation on Propagation Behavior of Hydraulic Fractures in Coal Seam during Refracturing

A Semianalytical Approach for Production of Oil from Bottom Water Drive Tight Oil Reservoirs with Complex Hydraulic Fractures

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