Study on the optimal design of volume fracturing for shale gas based on evaluating the fracturing effect—A case study on the Zhao Tong shale gas demonstration zone in Sichuan, China

AbstractHydraulic fracturing is the key technology in the development of shale gas reservoirs, and it mainly adopts volume fracturing technology to communicate hydraulic fractures with natural fractures to increase the drainage area. In view of the difficulty in characterizing the complex fractures created by multistaged fracturing in horizontal shale gas wells and the immaturity of fracturing optimization design methods, this study first evaluated the stimulation effect of fracturing technology based on treatment data and microseismic data. Then, the fracture characteristics after frac were considered, and a post-frac simulation was studied based on the discrete fracture network (DFN) model and the microseismic monitoring data as constraints. Finally, from the simulation results, an optimal design method of volume fracturing for shale gas was proposed based on the evaluation of the frac effects. The National Shale Gas Demonstration Zone in Zhaotong, Sichuan Basin was used as an example to study the optimal frac design of shale gas wells. The results show that (1) after optimizing the design, the optimal interval range is 50–70 m, the liquid volume of a single stage is 1800–2200 m3, the amount of sand is 80 m~120 t, and the slurry rate is 10–12 m3/min. (2) Two different frac design schemes were implemented in two wells on the same platform, and the production of the optimized design scheme was 14.7% greater than the original scheme. Therefore, the frac optimization design based on evaluating the fracturing effect can better guide the development of subsequent shale gas wells in this area.

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Feasibility Study on Technology Named Liquid Explosive Applied in Volume Fracturing Transformation of Shale Gas Reservoir

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.2281 ◽

2012 ◽

Vol 538-541 ◽

pp. 2281-2284

Author(s):

Jin Jun Wu ◽

Li Cai Liu

Keyword(s):

Feasibility Study ◽

Shale Gas ◽

Optimization Design ◽

Design Method ◽

High Energy ◽

Liquid Explosive ◽

Gas Reservoir ◽

Reservoir Characteristics ◽

Shale Gas Reservoir ◽

Volume Fracturing

According to Chinese shale gas reservoir characteristics and its exploitation situation, based on principle of high energy gas fracturing, combined with theory on volume transformation technology of shale gas reservoir, the feasibility study of liquid explosive technology applied in volume fracturing transformation of shale gas reservoir is precede. Through analyzing action mechanism of liquid explosive technology, studying forming mechanism about multi-crack system produced in shale gas reservoir, and analyzing shale gas reservoir characteristics and drilling and completion technologies, etc., proving the feasibility of technological principle and process design about liquid explosive technology applied in volume transformation of shale gas reservoir, meanwhile, proposing the design adopts the technology combined hydraulic fracturing and liquid explosive together. Also advising to establish theoretical model and optimization design method through series of studying and experiments, and to do field test application, so as to provide a new technology way for its exploration and exploitation.

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A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

Applied Sciences ◽

10.3390/app11073017 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3017

Author(s):

Qiang Gao ◽

Siyu Gao ◽

Lihua Lu ◽

Min Zhu ◽

Feihu Zhang

Keyword(s):

Optimal Design ◽

Optimization Design ◽

Design Method ◽

Fluid Structure Interaction ◽

Design Procedure ◽

Design Parameters ◽

Geometrical Parameters ◽

Fluid Structure ◽

Structure Interaction ◽

Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

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Optimization Research on Dynamic Balance of Spatial Engine under Limiting Shaking Moment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.626-627.693 ◽

2009 ◽

Vol 626-627 ◽

pp. 693-698

Author(s):

Yong Yong Zhu ◽

S.Y. Gao

Keyword(s):

Mathematical Model ◽

Objective Function ◽

Kinetic Analysis ◽

Optimization Design ◽

Design Method ◽

Dynamic Balance ◽

Optimized Design ◽

Design Variables ◽

The Mathematical Model ◽

Shaking Moment

Dynamic balance of the spatial engine is researched. By considering the special wobble-plate engine as the model of spatial RRSSC linkages, design variables on the engine structure are confirmed based on the configuration characters and kinetic analysis of wobble-plate engine. In order to control the vibration of the engine frame and to decrease noise caused by the spatial engine, objective function is choosed as the dimensionless combinations of the various shaking forces and moments, the restriction condition of which presents limiting the percent of shaking moment. Then the optimization design is investigated by the mathematical model for dynamic balance. By use of the optimization design method to a type of wobble-plate engine, the optimization process as an example is demonstrated, it shows that the optimized design method benefits to control vibration and noise on the engines and improve the performance practically and theoretically.

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A Displacement-Based Optimal Design Method of RC Frames Subjected to Minor Earthquakes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.594-597.795 ◽

2012 ◽

Vol 594-597 ◽

pp. 795-799

Author(s):

Gui Tao Chen ◽

De Min Wei

Keyword(s):

Optimal Design ◽

Optimization Design ◽

Virtual Work ◽

Design Method ◽

Horizontal Displacement ◽

Target Displacement ◽

Programming Technique ◽

Direct Displacement Based Design ◽

Rc Frames ◽

Displacement Based

A displacement-based optimization design method of RC structure was proposed by combining direct displacement-based design method with nonlinear programming technique. To avert the influence of target displacement, the stationary constraint displacement was presented, and the target displacement can be updated during the optimal design process. Principle of virtual work and Gaussian integral method was employed to simplify the explicit relationship between horizontal displacement and the section dimension. Comparison analysis of the local optimal results corresponding to different displacement shapes was conducted to achieve global optimal design. The numerical tests presented demonstrate the computational advantages of the discussed methods and suggesting that the proposed method is a reliably and efficiently tool for displacement-based optimal design.

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Structure Optimization of UHV RIP Oil-SF6 bushings Based on Improved Equal Margin Design Method and Back-Propagation Neural Network

E3S Web of Conferences ◽

10.1051/e3sconf/202126103040 ◽

2021 ◽

Vol 261 ◽

pp. 03040

Author(s):

Zhang Shiling

Keyword(s):

Field Distribution ◽

Optimization Design ◽

Design Method ◽

Back Propagation ◽

Back Propagation Neural Network ◽

Analytic Formula ◽

Optimized Design ◽

Thermal Coupling ◽

Coupling Calculation ◽

Temperature Factors

Equal margin design method based on the classic analytic formula is widely used in development of extra-high voltage bushing products, and its effectiveness and practicality have been fully validated. However, model and temperature factors have significant impact on internal E-field distribution of UHVAC and UHVDC bushing condenser, which traditional analytic formula is difficult to evaluate quantitatively, so it’s necessary to improve traditional equal margin design method. Firstly, basic principles of equal margin design method and its software package were briefly described, and the laws of model and temperature factors influencing on condenser E-field were investigated on FEM (finite element method) computing platform. Based on these, mathematical model of improved equal margin design method for bushing condenser was established, and flow chart of optimization process combining FEM electro-thermal coupling calculation with genetic algorithm was presented. The improved method was applied to design of UHV RIP oil-gas prototype to realize uniform axial E-field distribution along bushing condenser and equal partial discharge margin between adjacent foils. Bushing condenser was fabricated according to above optimized design structure, and has passed all type tests. In the paper, the FEM electro-thermal coupling calculation method was applied to the inner insulation optimization design to make bushing condenser’s design more suitable. The paper can provide some theoretical guidelines for research and development of other bushings in UHV level.

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A Novel Design Method for Optimizing the Diverter Dosage in Hydraulic Fracturing Using Three-Dimensionally Printed Fractures

10.2118/205779-ms ◽

2021 ◽

Author(s):

Meng Wang ◽

Mingguang Che ◽

Bo Zeng ◽

Yi Song ◽

Yun Jiang ◽

...

Keyword(s):

Shale Gas ◽

Design Method ◽

Pressure Rise ◽

Horizontal Wells ◽

Optimization Method ◽

Darcy Law ◽

Hydraulic Fractures ◽

Fracture Conductivity ◽

Fracture Simulation ◽

3D Printed

Abstract Application of diversion agents in temporarily plugging fracturing of horizontal wells of shale has becoming more and more popular. Nevertheless, the studies on determining the diverter dosage are below adequacy. A novel approach based on laboratory experiments, logging data, rock mechanics tests and fracture simulation was proposed to optimizing the dosage of diversion agents. The optimization model is based on the classic Darcy Law. A pair of 3D-printed rock plates with rugged faces was combined to simulate the coarse hydraulic fractures with the width of 2.0 ~ 7.0 mm. The mixture of the diversion agents and slickwater was dynamically injected to simulate the fracture in Temco fracture conductivity system to mimic the practical treatment to temporarily plugging the fracture. The permeability of the temporary plugging zone in the 3D-printed fractures was measured in order to optimize the dosage of the selected diversion agents. The value of Pnet (also the value of ΔP in Darcy Formula) required for creation of new branched fractures was determined using the Warpinski-Teufel Failure Rules. The hydraulic fractures of target stages were simulated to obtain the widths and heights. The experimental results proved that the selected suite of the diversion agents can temporarily plug the 3D-printed fractures of 2.0 ~ 7.0 mm with blocking pressure up to 15 MPa. The measured permeability of the resulting plugging zones was 0.724 ~ 0.933 D (averaging 0.837 D). The value of Pnet required for creation of branched fractures in shale of WY area (main shale gas payzone of China) was determined as 0.4 ~ 15.6 MPa (averaging 7.9 MPa) which means the natural fractures and/or weak planes with approaching angle less than 70° could be opened to increase the SRV. The typical dosage of the diversion agents used for one stage of the horizontal wells (averaging TVD 3600 m) was calculated as 232 ~ 310 kg. The optimization method was applied to the design job of temporarily plugging fracturing of two shale gas wells. The observed surface pressure rise after injection of diversion agents was 0.6 ~ 11.7 MPa (averaging 4.7 MPa) and the monitored microseismic events of the test stages were 37% more than those of the offset stages.

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Optimization Design Method of the Pre-Manufactured Hole of Flanging

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.395-396.1206 ◽

2013 ◽

Vol 395-396 ◽

pp. 1206-1211 ◽

Cited By ~ 1

Author(s):

Yang Li ◽

Zhong Lei Wang ◽

Xiao Li ◽

Gang Cheng

Keyword(s):

Finite Element ◽

Optimal Design ◽

Finite Element Simulation ◽

Optimization Design ◽

Design Method ◽

Line Length ◽

Theoretical Formula ◽

Equal Area ◽

Element Simulation ◽

Optimal Design Method

For the difficulty of calculating the size of the Pre-Manufactured hole of flanging, the formula was derived by using the theory of equal line length and the theory of equal area. And the formula was verified by finite element simulation. Due to theoretical formula has certain error, the optimal design method based on interpolation was put forward and optimization design the size of the Pre-Manufactured hole of flanging. Engineering example shows that this optimization design method is accuracy and convergence speed, and it can quickly calculate the the size of the Pre-Manufactured hole of flanging.

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An Optimization Design Method of Geometric Parameters of Skid Shoe Referring to Subject Weight of Marine Structures

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.678.325 ◽

2014 ◽

Vol 678 ◽

pp. 325-332

Author(s):

Feng Yan Yang ◽

Xiang Zhen Yan ◽

Zheng Rong Song ◽

Ming Wang Yang ◽

Zi Kun Zhao ◽

...

Keyword(s):

Optimization Design ◽

Design Method ◽

Plate Thickness ◽

Optimization Method ◽

Geometric Parameters ◽

Frame Structure ◽

Complex Method ◽

Optimized Design ◽

Original Design ◽

Marine Structures

The optimization design method of geometric parameters of skid shoe which is used to subject weight of marine structures is proposed. Considering skid shoe as steel frame structure, total weight and the bearing capacity of the skid shoe are selected as optimal objectives, and geometric parameters of the skid shoe are taken as design variables. Taking the strength, stiffness, local stability of the skid shoe as the constraint conditions, multi-objectives constraints optimization model of geometric parameters is established, and solved based on complex method. According to research results, a computer program has been developed using VC language. Then geometric optimum parameters of skid shoe in service of CNOOC are analyzed by the program. The results show that optimized design decreases steel volume, steel plate thickness by 28.7%, 18.4%, respectively, compared with original design. The optimization method has a series of advantages, such as simple model, fast calculating speed, high calculation accuracy.

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