Effect of Operating Parameters of Hydraulic Fracturing Technology and Reservoir Porosity on Fracture Geometry (original) (raw)
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Geomechanical Principles of Hydraulic Fracturing Method in Unconventional Gas Reservoirs
International Journal of Engineering, 2018
Unconventional gas production from shale formation is not new to oil and gas experts worldwide. But our research work was built around hydraulic fracturing technique with focus on the Perkins Kern-Nordgren (PKN) 1972 hydraulic fracturing model(s). It is a very robust and flexible model that can be used on two major shale reservoirs (with the assumption of a fixed height and fracture fluid pressure). The essence was to compare detailed geo-mechanical parameters extracted from wire-line logs with Perkin-C model to select the right well as candidate for simulation. It aided in the prediction production of shale gas from tight shale formations. These also helped in reviewing safe and economical ways of obtaining clean energy sources. Based on similarities in well and formation properties our research team subjected IDJE-2 well (located in the Agbada shale Formation of Niger Delta, Nigeria) to various conditions, equations and assumptions proposed by the study model while also validating our results with the PENOBSCOT L-30 well, located in Canada (with existing profound results from stimulations). The PENOBSCOT L-30 well (Case 1) and IDJE-2 well (Case 2) were both subjected to same conditions, equations and assumptions as applicable to the study model to enable us compare and evaluate stimulation performances. But both cases tend to react differently. However the fluid behavior at constant injection time increases at about 99.64%. Whereas, the maximum width at wellbore shows that a constant increase of fracture width will yield an increase in propant permeability, tensile strength and Poisson's ratio for Case 1 & 2. Our research results show how rock properties can affect fracture geometry and expected production rates from stimulated shale reservoir formations.
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.
Tạp chí Khoa học và Công nghệ biển
In the recent days, hydraulic fracturing technique has been widely used to improve oil production with different reservoir characteristics such as low or high formation permeability, low or high formation porosity, formation damage. However, previous research did not mention the optimization for fracturing parameters including the injection rate, injection time, and leak-off coefficient to stimulate the Oligocene E reservoir, which is based on optimum oil production performance at which maximum net present value has been achieved. The problems in the Oligocene reservoir are too low production rate due to high reservoir depth, high closure pressure up to 7,700 psi, low reservoir permeability, low porosity and geological structure with heterogeneous reservoir, high temperature, resulting in low conductivity. To deal with these problems, fracturing technique is the best choice to stimulate this reservoir. The study focuses on optimizing fracturing parameters by applying the CCD and RSM...
2009
Hydraulic fracturing is a process applied to boreholes to improve the ability of uids (such as oil and gas) to ow to the hole and be recovered. Recent investigation has shown that fractures can play a major role in the productivity of low permeability formations. The Ahwaz oil eld is one of the largest in South West Iran. The Bangestan reservoir in this eld, with a suitable amount of oil in place and good rock reservoirs, has been selected for the present research work. The pressure pro le has been calculated in tight reservoirs in a few wells, for the purpose of hydraulic fracturing operation studies. In this work, the pore pressure was calculated by using the available eld data in the carbonated reservoir of the Ahwaz eld. The results indicate that the Ilam formation could be a good candidate for hydraulic fracturing.
Effects of Fracture Properties on Oil Recovery in Tight Reservoirs
Journal of Petroleum Engineering & Technology , 2016
Unconventional reservoirs, characterized by low permeability are gradually becoming a force to reckon with in today’s world owing to the rapid depletion of conventional resources. However, low oil production from tight reservoirs can be mitigated by implementing hydraulic fracturing. In this study, Schlumberger’s eclipse-100 simulator was used to simulate various scenarios in order to determine the best fracture geometry and the effects of fracture properties on oil recovery. The properties considered were fracture half-length, width and number. Oil recovery from the tight reservoir was found to be 0.47% OIP and the application of hydraulic fracturing increased the recovery to 4.78%. OIP sensitivity analysis was carried out by varying well trajectory, porosity, permeability and wettability. It was found out that, fracture geometry of 300 ft halflength, 1 inch width and a fracture number of 15 is ideal for this reservoir, both technically and economically. An increase in the fracture number affected the spacing greatly. As the number increased, initial production from the reservoir increased. However, cumulative production declined with continued increase in fracture number as spacing decreased. The fracture half-length had a more significant impact on the early time behavior as a result of the fractures reaching further into the reservoir. Increase in fracture width impacted on the late time production behavior of the well by maintaining production for a longer duration. Variations in the reservoir properties after obtaining the optimum case show that hydraulic fracturing is applicable to tight reservoirs.
Analysis on the effect of different fracture geometries on the productivity of tight gas reservoirs
Malaysian Journal of Fundamental and Applied Sciences, 2020
Tight gas reservoirs are unconventional reservoir assets which have been the focus of major research in the petroleum industry owing to the global decline in conventional reservoirs. They are widely unlocked by creating hydraulic fractures in the formation to increase the flow capacity and productivity. The objective of this paper is to analyze different fracture geometries and their effect on tight gas production. The reservoir simulation model of the tight gas reservoir has been built with single porosity approach. A single vertical well with a single stage fracture has been used in the model to predict the behavior of fracture geometry. The major parameters of fracture geometry studied are fracture half-length, fracture width, and fracture height. Four sensitivities are run over different fracture geometry that is constant height and constant width, constant height and changing width, changing height and constant width, and changing height and changing width, while increasing the fracture half-length from 100 ft to 500 ft in each case. Sensitivity analysis exhibited that keeping the hydraulic fracture at constant height and constant width while increasing the fracture half-length resulted in enhanced tight gas productivity i.e. 11.63%, 14.14%, 16.06%, 17.48%, and 18.89% at hydraulic fracture half-lengths of 100 ft, 200 ft, 300 ft, 400 ft, and 500 ft, respectively, compared to other types of fracture geometry.
Petroleum Science and Technology, 2010
Worldwide there are vast reserves of natural gas trapped in tight sandstone formation and due to the low viscosity of natural gas it can be easily recovered. To produce this huge amount of reserve from low permeability formation economically, hydraulic fracturing can be applied. Therefore, the objective of hydraulic fracturing for well stimulation is to increase well productivity by creating a highly conductive path (compared to reservoir permeability) a distance away from the wellbore into the formation. The post treatment performance provides a good indication of stimulation success, whereas, pressure transient (PTA) and production data analysis for hydraulically fractured vertical well remains the most applied method to determine the reservoir and fracture parameters. Therefore, this analysis is a key element for optimization of hydraulic fracturing process and forecasting well performance. This paper discus the analysis of pressure and production data from hydraulically fractured vertical well in low permeability sandstone reservoir. Whereas, Pressure transient analysis is used to evaluate the effective fracture parameters such as fracture half-length, fracture conductivity and reservoir properties. Field example of application of production data analysis for vertical fractured well are presented. The aim of this study is to evaluate the gas well productivity as a result of hydraulic fracturing treatments compared to the pre fracturing productivity and to estimate the petrophysical properties of the gas well from MIT testing data. Moreover, a discussion of how significant the increment in gas productivity was achieved with a very high propped fracture treatment success rate, is also presented. Furthermore, a view of how the correct design of fracture treatments can enhance reservoir performance and the recovery rate is discussed in details.
Optimization Of Multi-Zone Unconventional (Shale) Gas Reservoir Using Hydraulic Fracturing Technique
2015
Hydraulic fracturing is one of the most important stimulation techniques available to the petroleum engineer to extract hydrocarbons in tight gas sandstones. It allows more oil and gas production in tight reservoirs as compared to conventional means. The main aim of the study is to optimize the hydraulic fracturing as technique and for this purpose three multi-zones layer formation is considered and fractured contemporaneously. The three zones are named as Zone1 (upper zone), Zone2 (middle zone) and Zone3 (lower zone) respectively and they all occur in shale rock. Simulation was performed with Mfrac integrated software which gives a variety of 3D fracture options. This simulation process yielded an average fracture efficiency of 93.8%for the three respective zones and an increase of the average permeability of the rock system. An average fracture length of 909 ft with net height (propped height) of 210 ft (average) was achieved. Optimum fracturing results was also achieved with maxi...
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.
An analitical study of hydraulic fracturing optimization for tight shale formation
21th International Petroleum and Natural Gas Congress and Exhibition of Turkey, 2023
Hydraulic fracturing optimization is a critical aspect of improving the recovery of unconventional shale formation. This paper discusses the use of different types of proppants, rate optimization, and proppant amount optimization to improve hydraulic fracturing techniques. The paper begins with a discussion of proppant selection, which is a critical aspect of hydraulic fracturing. The authors highlight the importance of proppant endurance in holding the fracture opening and provide a range of proppants suitable for different confining pressures. Tables and charts are included to illustrate the permeability values of various proppants under different closure stress values. This section also emphasizes the significance of proppant shape in creating a more conductive path in the fracture. The next section of the paper discusses the methodology used in the study, including the Fracpro software simulation parameters. The authors then delve into the optimization of proppant specific gravity and the results of their experiments with five different types of proppants. The paper highlights the impact of proppant specific gravity on fracture width and dimensionless conductivity (FCD). The authors also focus on the optimization of pumping rate, which is an essential parameter of hydraulic fracturing operations. The paper includes simulation studies conducted to determine the effects of pumping rate on fracture parameters such as propped length and propped height. The authors highlight the relationship between rate and FCD and how it is affected by permeability values of the proppant. Finally, the paper discusses proppant amount optimization, which is a critical point of hydraulic fracturing optimization. The authors provide an overview of the results of the experiments conducted to determine the optimal amount of proppant required for different hydraulic fracturing operations. Overall, this paper provides valuable insights for researchers and engineers working to improve hydraulic fracturing techniques for tight shales formation. The authors use a combination of theory, experiments, and charts to provide a comprehensive overview of the various aspects of hydraulic fracturing optimization.