scholarly journals Simulação de Reservatórios de Óleo Leve com Poço Horizontal Hidraulicamente Fraturado

2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Helio Souto
Keyword(s):  
Hydraulic Fracturing ◽  
Reservoir Simulation ◽  
Horizontal Well ◽  
Fractured Reservoirs ◽  
Horizontal Wells ◽  
Preconditioned Conjugate Gradient ◽  
Hydraulic Fractures ◽  
Tight Oil ◽  
Wellbore Pressure ◽  
Fractured Horizontal Wells

<p>Since the 1960s, because of the relevance to the oil industry, the numerical simulation of hydrocarbon reservoirs has received special attention and has been the subject of extensive studies. The main goal of computational modeling and the use of numerical methods for reservoir simulation is to allow better placement and control of wells, so that there is a optimized oil recovery. In this work, production of hydraulically fractured horizontal wells in light tight oil reservoirs will be studied. In this case, fractures do not form a continuous conductive network and can communicate hydraulically with only the horizontal producer well. In order to do that, a simulator for three-dimensional oil flow in reservoirs, suitable for applications in the field scale, already developed, using the Cartesian coordinate system and a finite difference approach, will be applied for the study of hydraulically fractured horizontal wells. Originally, this simulator and its grid refinement tools had been used only on the simulation of naturally fractured reservoirs. The nonlinear partial differential equation resulting from physical-mathematical modeling, written in terms of pressure, will be solved numerically after discretization and linearization using the Preconditioned Conjugate Gradient method. The main objective is to study the combined effects of hydraulic fractures and horizontal well on the wellbore pressure profile, considering different light tight oil production scenarios. Numerical simulations displayed the influence of important parameters on the well-reservoir system in study, such as fracture permeability and matrix porosity. A study of this type is relevant on the discussion of reservoir production strategies, helping on the decisions about a hydraulic fracturing operation in order to obtain economic viability for the hydrocarbons recovery project.</p><p><strong>Keywords</strong>: reservoir simulation, light tight oil, horizontal well, hydraulic fracturing, nite diferences method.</p>

The Interpretation Technique of Rate Transient Analysis Data in Fractured Horizontal Wells

2021 ◽  
Author(s):  
Ruslan Rubikovich Urazov ◽  
Alfred Yadgarovich Davletbaev ◽  
Alexey Igorevich Sinitskiy ◽  
Ilnur Anifovich Zarafutdinov ◽  
Artur Khamitovich Nuriev ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Transient Analysis ◽  
Horizontal Well ◽  
Horizontal Wells ◽  
Data Interpretation ◽  
Analysis Data ◽  
Well Logging ◽  
Rate Transient Analysis ◽  
Fractured Horizontal Well ◽  
Fractured Horizontal Wells

Abstract This research presents a modified approach to the data interpretation of Rate Transient Analysis (RTA) in hydraulically fractured horizontal well. The results of testing of data interpretation technique taking account of the flow allocation in the borehole according to the well logging and to the injection tests outcomes while carrying out hydraulic fracturing are given. In the course of the interpretation of the field data the parameters of each fracture of hydraulic fracturing were selected with control for results of well logging (WL) by defining the fluid influx in the borehole.

scholarly journals A Semianalytical Model for Multiple-Fractured Horizontal Wells with SRV in Tight Oil Reservoirs

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Jiahang Wang ◽  
Xiaodong Wang ◽  
Wenxiu Dong
Keyword(s):  
Great Influence ◽  
Horizontal Wells ◽  
Oil Reservoirs ◽  
Nonlinear Flow ◽  
Hydraulic Fractures ◽  
Tight Oil ◽  
Transient Pressure ◽  
Type Curves ◽  
Tight Oil Reservoirs ◽  
Fractured Horizontal Wells

The paper developed a new semianalytical model for multiple-fractured horizontal wells (MFHWs) with stimulated reservoir volume (SRV) in tight oil reservoirs by combining source function theory with boundary element idea. The model is first validated by both analytical and numerical model. Then new type curves are established. Finally, the effects of SRV shape, SRV size, SRV permeability, and parameters of hydraulic fractures are discussed. Results show that SRV has great influence on the pressure response of MFHWs; the parameters of fractures, such as fracture distribution, length, and conductivity, also can affect the transient pressure of MFHWs. One novelty of this model is to consider the nonlinear flow around hydraulic fracture tips. The other novelty is the ability to model the shape of the SRV, production behavior of different fractures, and interfaces. Compared to numerical and analytic methods, this model can not only reduce extensive computing processing but also show high accuracy.

Analytical Solutions for a Quad-Linear Flow Model Derived for Multistage Fractured Horizontal Wells in Tight Oil Reservoirs

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Wendong Wang ◽  
Mohammad Shahvali ◽  
Yuliang Su
Keyword(s):  
Analytical Solutions ◽  
Hydraulic Fracture ◽  
Horizontal Wells ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Pressure Derivative ◽  
Linear Flow ◽  
Wellbore Pressure ◽  
Tight Oil Reservoirs ◽  
Fractured Horizontal Wells

Analysis of microseismic field data shows that the stimulated reservoir volume (SRV) in unconventional reservoirs partially covers the area between hydraulic fracture stages. Consequently, we are often faced with an effective fracture network area (EFNA) rather than a full SRV in such reservoirs. In this paper, we develop a new semi-analytical solution for pressure of hydraulically fractured horizontal wells in tight oil reservoirs with various SRV sizes. Our model is based on four linear flow regions including the hydraulic fracture, the stimulated reservoir, the unstimulated reservoir, and the outer reservoir region. Flow in each region is represented by a set of governing equations and boundary conditions that are coupled to those of other regions. The dual-porosity formulation represents the SRV, while single-porosity formulation is used for other flow regions. We transform the coupled system of equations into Laplace domain, solve for wellbore pressure, and invert the solutions back to time domain numerically. We validate the semi-analytical solutions by comparing them to other semi-analytical solutions in the literature for the special case of trilinear flow. We further validate the quad-linear flow solutions using numerical simulation. Based on the semi-analytical solutions, we generate logarithmic plots of wellbore pressure and pressure derivative. Moreover, we perform sensitivity studies to present the degree to which the solutions vary as size and other properties of the SRV change.

Productivity and Drainage Area of Fractured Horizontal Wells in Tight Gas Reservoirs

2008 ◽  
Vol 11 (05) ◽  
pp. 902-911 ◽  
Author(s):  
Flavio Medeiros ◽  
Erdal Ozkan ◽  
Hossein Kazemi
Keyword(s):  
Horizontal Well ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Drainage Area ◽  
Dual Porosity ◽  
Hydraulic Fractures ◽  
Tight Gas ◽  
Natural Fractures ◽  
Tight Formations ◽  
Fractured Horizontal Wells

Summary This paper discusses the performance and productivity of fractured horizontal wells in heterogeneous, tight-gas formations. Production characteristics and flow regimes of unfractured and fractured horizontal wells are documented. The results show that if hydraulic fracturing affects stress distribution to create or rejuvenate natural fractures around the well, the productivity of the system is significantly increased. Unless there is significant contrast between the conductivities of the hydraulic and natural fractures, hydraulic fractures may not significantly contribute to the productivity. For extremely tight formations, the effective drainage area may be limited to the naturally fractured region around the well and the hydraulic fractures. It is also shown that very long transient flow periods govern the productivity and economics of fractured horizontal wells in tight formations. The results of this study are also applicable to oil production from fractured shale. Introduction Economic gas and oil production from low permeability reservoirs has been a challenge for the oil and gas industry. Because most of the high permeability reservoirs have been exploited and many low permeability reservoirs remain undeveloped, the latter have taken the industry attention recently. Particular attention has been given to tight-gas reservoirs with permeability in the range of micro-Darcies or below and to oil accumulation in fractured shale. Hydraulically fractured horizontal wells are the proven technology to produce oil and gas from tight formations. Hydraulic fractures reduce well drawndown, increase the productivity of horizontal wells by increasing the surface area in contact with formation, and provide high conductivity paths to the wellbore. Depending on in-situ stress orientation, hydraulic fractures can be parallel (longitudinal) or perpendicular (transverse) to horizontal well axis. Project economics in tight formations, however, depends strongly on well spacing and the number of hydraulic fractures required to drain the reservoir efficiently. Field evidence indicates that the drainage areas of fractured horizontal wells in tight formations may be limited to a rectangular region confining the horizontal well and the transverse hydraulic fractures. Also, there has been evidence that hydraulic fracturing in tight formations changes stresses in fracture drainage area, which could create or rejuvenate natural fractures in the near-vicinity of the horizontal well. This fracture network, which may be characterized as a dual-porosity system, may contribute significantly to improve productivity of the fractured horizontal well. Much work has been done (Soliman et al. 1990; Larsen and Hegre 1994; Temeng and Horne 1995; Raghavan et al. 1997; Wan and Aziz 1999; Al-Kobaisi et al. 2006) to investigate pressure-transient analysis and short- and long-term productivity of horizontal wells with single or multiple hydraulic fractures. The effect of a dual-porosity zone surrounding hydraulic fractures, however, has not been considered in the previous studies. The main objective of this study is to investigate the combined effects of a dual-porosity region and hydraulic fractures on the productivity of horizontal wells. The results presented in this work are based on a semianalytical model developed by Medeiros et al. (2006). The model was derived from the Green's function formulation of the solution for the diffusivity equation (Gringarten and Ramey, 1974, Ozkan and Raghavan, 1991a, 1991b) and has the capability to incorporate local heterogeneities. In this work, we use the semianalytical model to incorporate induced finite-conductivity fractures (transverse and longitudinal) along the horizontal well and naturally fractured zones around the hydraulically fractured horizontal well by using the dual-porosity idealization. We use the example data sets given in Tables 1 through 3 to consider different cases of horizontal wells with and without induced and natural fractures.

New Semi-Analytic Technique to Determine Horizontal Well PI in Fractured Reservoirs

2005 ◽  
Vol 8 (02) ◽  
pp. 123-131 ◽  
Author(s):  
Peter A. Fokker ◽  
Francesca Verga ◽  
Paul Egberts
Keyword(s):  
Horizontal Well ◽  
Flow Behavior ◽  
Fractured Reservoirs ◽  
Horizontal Wells ◽  
Homogeneous Layer ◽  
Hydraulic Fractures ◽  
Phase Flow ◽  
Good Correspondence ◽  
Well Productivity ◽  
Well Models

Summary Simplified analytical relations derived for homogeneous formations are usually applied to the determination of the productivity of horizontal wells, regardless of the presence of heterogeneities in the reservoir. Furthermore, complex well architectures and the wealth of completion options currently available cannot be taken into account properly because the well trajectory can only be schematized as a single horizontal wellbore. However, the use of numerical reservoir simulators to reliably forecast the productivity of horizontal wells draining heterogeneous reservoirs may be time-prohibitive or not feasible because of a lack of sufficiently detailed information, especially during the appraisal phase or the early stages of production. A new semianalytic technique is proposed in this paper to solve the inflow equations in an approximate yet reliable manner. A solution to 3D problems of single-phase flow into a horizontal well, taking into account friction in the wellbore, is provided for both single-layer reservoirs and reservoirs comprising two interfering layers. The method also has been extended to describe the fluid flow when the well intercepts one or more fractures. The presented technique allows very fast calculation of the well productivity in oil and gas reservoirs, offering great flexibility in the placement and architecture of the wells. The method has been applied to two field cases for which the well productivity under pseudosteady-state conditions was measured. One of these is a 200-m-long horizontal well draining an isotropic carbonatic reservoir and intersected by a natural low-conductivity fracture. The other is a similar well, intercepting a natural high-conductivity fault, but the oil-bearing formation is anisotropic. Good correspondence was found between the actual productivity and the predictions obtained by application of the proposed semianalytic technique. Introduction Horizontal wells are common practice in the present hydrocarbon industry, and smart wells (including multilateral completions and wells with selective access of different zones) are becoming increasingly commonplace. The modeling of such wells is, in many cases, not ideal. Areas in which improvements are welcome are well testing, well models in reservoir simulators, and fast models for quick assessment of many field-development options. Further, the handling of natural or hydraulic fractures is often suboptimal. In reservoir simulation, fine grids need to be selected to properly capture the flow behavior close to the well. Moreover, most reservoir simulators are not equipped with extensive well models, which are required when friction in the well becomes important or when two-phase flow develops in the well. This situation has prompted the development of a number of analytical and semianalytical tools, some of which are intended for implementation in a reservoir simulator. Most of the first models, as well as many of the more recent models, assume either constant influx density along the well or infinite well conductivity in a single homogeneous layer. Dikken introduced the effect of well conductivity for a single horizontal well in a homogeneous formation. He started with the assumption that the flow is mainly perpendicular to the wellbore, which allowed him to reduce the reservoir to a 2D flow domain, coupled to a friction model in the well. Others followed this approach, but 3Dmodels were developed as well. A second kind of extension are the multilayer models. Lee and Milliken and Kuchuk and Habashy used a method of reflection and transmission, while Basquet et al. used a "quadrupole" method relating the pressures between the various layers. The multilayer models are also, however, still limited to constant-influx or infinite-conductivity wells.

An Improved Methodology for Gridding Fractured Reservoirs for Simulation

2021 ◽  
Author(s):  
Sheldon Gorell ◽  
Jim Browning ◽  
Justin Andrews
Keyword(s):  
Reservoir Simulation ◽  
Unstructured Grids ◽  
Fractured Reservoirs ◽  
Simulation Models ◽  
Horizontal Wells ◽  
Design Parameters ◽  
Structured Grids ◽  
Fractured Horizontal Wells ◽  
The Impact ◽  
Base Grid

Abstract A significant amount of research for gridding of complex reservoirs, including models with fractures, has focused on use of unstructured grids. While models with unstructured grids can be extremely flexible, they can also be expensive, both in configuring, computationally, and visual display. Even with this focus on unstructured grids, most reservoir simulation models are still built on structured grids. Current methods for creating reservoir simulation models with structured grids often involve defining a base grid upfront and then "somehow" inserting one or more Features of Interest (FOI's) into the model. Applied to fractured horizontal wells with many stages it can be extremely difficult to accurately align wells and completions within a pre-existing simulation grid. This work describes and demonstrates a methodology to resolve such issues. This approach changes the order of model design and creation steps. This paper describes the process where FOI's are identified, a base grid is designed around the FOI's, then local grid refinements (LGR's) are defined as desired. Applied to a horizontal well with fractures, the well and completion locations are defined before the detailed grid definition is created. This process is illustrated for generalized FOI's, and then applied to fractured horizontal wells. Formulas for creation of models for wells with evenly space homogeneous completions are presented. Numerical testing and analyses are presented that show the impact of the gridding parameters and various design parameters on performance of reservoir simulations.

Experience in Optimizing the Location and Parameters of Multistage Hydraulic Fractures for a Multilateral Well Based on Reservoir Simulation

2021 ◽  
Author(s):  
Vil Syrtlanov ◽  
Yury Golovatskiy ◽  
Konstantin Chistikov ◽  
Dmitriy Bormashov
Keyword(s):  
Hydraulic Fracturing ◽  
Reservoir Simulation ◽  
Optimal Placement ◽  
Hydraulic Fractures ◽  
Low Permeability ◽  
Advantages And Disadvantages ◽  
Modeling Methods ◽  
Multistage Hydraulic Fracturing ◽  
Determination Of Parameters

Abstract This work presents the approaches used for the optimal placement and determination of parameters of hydraulic fractures in horizontal and multilateral wells in a low-permeability reservoir using various methods, including 3D modeling. The results of the production rate of a multilateral dualwellbore well are analyzed after the actual hydraulic fracturing performed on the basis of calculations. The advantages and disadvantages of modeling methods are evaluated, recommendations are given to improve the reliability of calculations for models with hydraulic fracturing (HF)/ multistage hydraulic fracturing (MHF).

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