Horizontal Well Fracturing Optimization Numerical Simulation (original) (raw)
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SIMULATION STUDY ON HORIZONTAL WELLS OF FRACTURING IN TIGHT OIL RESERVOIRS
Tight reservoir has poor porosity and permeability, so it is necessary to use volume fracturing in horizontal wells to increase seepage area and communicate natural fractures, so as to realize high efficiency production. In order to comprehensively analyze influence factors of fracture network, and provide scientific geological model for the next production forecast, the method system of key parameters of natural fracture and fracture network is established, design the simulation model, which including the formation of the geological model, natural fracture simulation and fracture network simulation integrated software the 3 part, analyzes the influence of brittleness coefficient, horizontal stress difference, natural fracture, net pressure changes caused by fracturing fluid displacement and fracturing fluid volume parameters on fracture network size and communication. In depth analysis of these factors can provide reference for the field.
2016
Hydraulic fracturing (HF), as a stimulation technique in petroleum engineering, has made possible the oil production from reservoirs with very low permeability. The combination of horizontal drilling and multiple HF with various perforation angles has been widely used to stimulate oil reservoirs for economical productions. Despite the wide use of HF, there are still ambiguous aspects that require more investigation. Therefore, optimizing the geometry of the initial fractures using numerical methods is of high importance in a successful HF operation. Different geometrical parameters of the initial HF cracks including patterns, spacings, crack lengths, and perforation phase angles were modeled using the higher order displacement discontinuity method (HODDM) in horizontal and vertical oil wells. Several well-known issues in HF such as crack interference and crack arrest were observed in certain patterns of the HF cracks. Also the best possible arrangements of the HF cracks were determi...
Taheri Shakib, J. Jalalifar, H., 2012
Hydraulic fracturing in the fractured reservoirs plays a significant impact on the production rate. In this study, the hydrostatic condition is taken into account, the hydraulic fracturing operation was applied in every direction usinga written distinct element code. In each direction the hydraulic fracture is applied with different lengths and in each level the amount of production is predicted. The impact of interaction of natural fractures and hydraulic fractures on the amount of production is discussed and the number of natural fractures which are intersected by hydraulic fractures is presented. Hydraulic fracturing operation in different directions with different lengths is economically analyzed. In fractured reservoirs the best scenario is that the hydraulic fracture is created in a direction that intersects a group of high permeable natural fractures/parts of the reservoir that are actively participating in flow or the parts with high pore pressures and no connection to the well. The reason is that connecting the natural fractures which are near the well does not have a significant effect on the production rate. According to the results, creating the hydraulic fractures in a direction with no fractures significantly affects the production rate.
The Analysis of Dynamic Data of Multi-Fractured Horizontal Well Preliminary Application Research
Advances in Petroleum Exploration and Development, 2013
Multi-fractured horizontal well’s model is complicated, which have to consider lots of parameters and bring other difficulties for the analysis of dynamic data. This paper intends to identify the difference from a theoretical perspective first and consider the nonlinearity of numerical horizontal method can explain or evaluate for these wells. Then this paper based on an actual multi-fractured horizontal well of gas and utilize the new model to analysis of dynamic data of multi-fractured horizontal well with different analysis method, through contrast with each result concluded that the nonlinearity of numerical horizontal model is the most appropriate for the analysis of dynamic data of multi-fractured horizontal well. The nonlinearity of numerical horizontal method has considered interferences between fractures and nonlinearity PVT and other factors, which are advanced than other methods and this method is the most appropriate for the analysis of dynamic data of multi-fractured ho...
Study of Horizontal Multistage Hydraulic Fracturing of a Reservoir
Chemistry and Technology of Fuels and Oils, 2017
Horizontal well drilling technology has gained widespread popularity in recent years, especially for developing shale gas fields. In this paper, we propose a 3D model for calculating process parameters, based on the hypothesis that an elliptical crack forms as a result of hydraulic fracturing. Calculations according to this model can be used to determine the net pressure and the stress distribution near the cracks formed.
SPE Annual Technical Conference and Exhibition, 2015
Multi-stage hydraulic fracturing together with horizontal drilling plays an important role in the economic development of unconventional reservoirs. However, according to field analysis of stimulation effectiveness, only a small percentage of perforation clusters contribute to most of the well production. One reason for this low effectiveness is that multiple fractures do not take the same amount of fluid and proppant due to fracture interaction (i.e., stress shadow effects). Unfortunately, how best to minimize the negative effects of stress shadowing is still poorly understood in the petroleum industry. In this paper, we analyzed this problem in order to promote more uniform fracture growth using our complex hydraulic fracture development model. We employed our fracture propagation model that couples rock deformation and fluid flow in the fracture and horizontal wellbore. Partitioning of flow rate between multiple fractures was calculated by analogizing to the electric circuit netw...
Fracturing Parameters in Petroleum Reservoirs and Simulation
Advances in Material Sciences and Engineering, 2020
The increasing demand for crude oil makes it necessary to consider factors that increase the productivity of the reservoirs. One of these factors is fracture that is found naturally or produced hydraulically, where the fracture improves reservoir flow and connectivity. The most common characteristics of naturally fractured reservoirs (NFRs) are the fractures directionality. In this review, the most important characteristics and parameters that affect the fracture have been explained. In addition, the simulations of the fracture phenomena have been cleared. The difference among the models that solved the fracture problems are; discrete fracture model (DFM), dual porosity model (DPM), embedded discrete fracture model (EDFM), and hybrid models DP and EDFM (DP + EDFM) are shown with characteristics of each model. The present study focused on the shape factor and the direction of the fracture to show their effects on the performance of the petroleum reservoir. In addition, the review of general important parameters for the fractured reservoirs has been presented.
Processes
The multifracture competitive growth from a horizontal well is an essential issue in multi-cluster fracturing design. In recent years, extremely limited entry (ELE) fracturing has been implemented to promote uniform multifracture growth. However, the mechanism of multifracture growth and ELE design remain unclear. Based on the planar three-dimensional multifracture propagation model, a multi-cluster horizontal well fracturing model that considers ELE design has been developed. The model considers flow in the wellbore and fluid filtration loss in the fracture. The simulator enables the simulation and analysis of non-uniform in situ stress, filtration loss, and fracture properties. Using this program, we simulated the propagation process of multiple clusters of fractures in ELE fracturing of horizontal wells. The results show the following: The perforation friction in the ELE fracturing can counteract the difference in fluid allocation caused by stress interference, allowing all clust...
Productivity calculation and distribution of staged multi-cluster fractured horizontal wells
Petroleum Exploration and Development, 2014
Applying the potential theory and the superposition principle, the authors derived the linear productivity equations of staged multi-cluster fractured horizontal well considering finite and infinite conductivity fractures, respectively. The cluster yields and total yield were obtained by solving these equations numerically. A concrete example is used to analyze the productivity distribution of the fractured horizontal well and the influence of fracture parameters on it. When the fracture conductivities are infinite, the total productivity decreases significantly with the decrease of all fractures' half-lengths; outer fractures near the endpoints of the horizontal wells contribute most to the total productivity, and fractures on the edges contribute more than the middle ones within the same stage. When the fracture conductivities are finite, the contribution of outer fractures near the endpoints of the horizontal wells to the total productivity decreases, and the contribution of middle fractures within each stage increases significantly, but the overall distribution characteristics are in accord with the former case. Fracture conductivities have a great influence on the productivity, but they are not linearly correlated. Three stages and two clusters per stage can ensure high productivity, and during fracturing design, one should try to increase fracture half-lengths and fracture conductivities, especially for outer fractures near the endpoints of the horizontal well, and there exists an optimal value for the fracture conductivities.
Petroleum Science and Technology, 2010
Hydraulic fracturing is a key technology for the development of unconventional resources such as shale gas. Due to the existence of numerous bedding planes, shale reservoirs can be considered typical anisotropic materials. In anisotropic shale reservoirs, the complex hydraulic fracture network (HFN) formed by the interaction of hydraulic fracture (HF) and bedding plane (BP) is the key to fracturing treatment. In this paper, considering the anisotropic angle, stress state and injection rate, a series of hydraulic fracturing experiments were conducted to investigate the effect of anisotropic characteristics of shale reservoirs on HFN formation. The results showed that the breakdown pressure increased first and then decreased when the anisotropic angle changed at 0 •-90 • , while the circumferential displacement had the opposite trend with a small difference. When θ = 0 • , fracturing efficiency of shale specimens was much higher than that under other operating conditions. When θ ≤ 15 • , the bedding-plane mode is ubiquitous in all shale reservoirs. While θ ranged from 30 •-45 • , a comprehensive propagation pattern of bedding-plane and crossing is presented. When θ ≥ 60 • , the HFN pattern changes from comprehensive mode to crossing mode. The propagation pattern obtained from physical experiments were verified by theoretical analysis. The closure proportion of the circumferential displacement was the highest when the propagation pattern was the bedding-plane mode (θ ≤ 15 •), following by crossing. The closure proportion was minimum only when the bedding-plane and crossing mode were simultaneously presented in the HFN. The results can provide some basic data for the design in hydraulic fracturing of tight oil/gas reservoirs.