Proppant Transport in Hydraulic Fractures by Creating a Capillary Suspension

2021 ◽  
Author(s):  
Ayomikun Bello
Keyword(s):  
Hydraulic Fracturing ◽  
Significant Risk ◽  
High Viscosity ◽  
Hydraulic Fractures ◽  
Main Task ◽  
Low Viscosity ◽  
Fracturing Fluids ◽  
Geological Conditions ◽  
Fracture Development ◽  
The Impact

Abstract Slick water fracturing fluids with high viscosity and minimal friction pressure losses are commonly employed in hydraulic fracturing nowadays. At the same time, high injection rates can be used to perform hydraulic fracturing to get the calculated fracture sizes. The conventional algorithm for conducting a standard proppant hydraulic fracturing includes performing a pressure test using a linear gel without a trial proppant pack to determine the quality of communication with the formation and the initial parameters of the fracture; and performing a mini-hydraulic fracturing on a cross-linked gel with a trial proppant pack (1000 - 2000 kg) to assess the parameters of the fracture development used to correct the design of the main hydraulic fracturing operation. However, in complex geological conditions associated with the presence of small clay barriers between the target formation and above or below the water-saturated layers, as well as in low-productive formations, this conventional method of conducting hydraulic fracturing operations using high-viscosity fluids is not always suitable. Hydraulic fracturing in thin-layer formations is associated with a significant risk of the tightness established by the fracture being broken, as well as fluids contained in the underlying or overlying layers being involved in the drainage process. Hydraulic fracturing in low-productive formations creates fractures that are similar in shape to radial fractures, reducing the efficiency and profitability of the impact due to inefficient use of materials and reagents. The main task in this situation is to limit the height of the fracture development and increase their length. It is necessary to use low-viscosity fracturing fluids with a high ability to transfer proppants to reduce the specific pressure in the fracture and control the height of the rupture. The goal of this research is to develop such fluid.

On the Impact of Liquid Drops on Immiscible Liquids

2016 ◽  
Author(s):  
Eduardo Castillo-Orozco ◽  
Ashkan Davanlou ◽  
Pretam K. Choudhury ◽  
Ranganathan Kumar
Keyword(s):  
Oil Spills ◽  
Silicone Oil ◽  
Density Ratio ◽  
High Viscosity ◽  
Impact Behavior ◽  
Immiscible Fluid ◽  
Liquid Droplets ◽  
Liquid Drops ◽  
Low Viscosity ◽  
The Impact

The release of liquid hydrocarbons into the water is one of the environmental issues that have attracted more attention after deepwater horizon oil spill in Gulf of Mexico. The understanding of the interaction between liquid droplets impacting on an immiscible fluid is important for cleaning up oil spills as well as the demulsification process. Here we study the impact of low-viscosity liquid drops on high-viscosity liquid pools, e.g. water and ethanol droplets on a silicone oil 10cSt bath. We use an ultrafast camera and image processing to provide a detailed description of the impact phenomenon. Our observations suggest that viscosity and density ratio of the two media play a major role in the post-impact behavior. When the droplet density is larger than that of the pool, additional cavity is generated inside the pool. However, if the density of the droplet is lower than the pool, droplet momentary penetration may be facilitated by high impact velocities. In crown splash regime, the pool properties as well as drop properties play an important role. In addition, the appearance of the central jet is highly affected by the properties of the impacting droplet. In general, the size of generated daughter droplets as well as the thickness of the jet is reduced compared to the impact of droplets with the pool of an identical fluid.

scholarly journals Hydromechanical-Coupled Cohesive Interface Simulation of Complex Fracture Network Induced by Hydrofracturing with Low-Viscosity Supercritical CO2

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Xin Cai ◽  
Wei Liu
Keyword(s):  
Hydraulic Fracturing ◽  
Supercritical Co2 ◽  
Fracture Propagation ◽  
Zone Model ◽  
Hydraulic Pressure ◽  
Small Aperture ◽  
Complex Fracture ◽  
Low Viscosity ◽  
Fracturing Fluids ◽  
Low Viscosity Fluids

Abstract Hydraulic fracturing experiments with low-viscosity fluids, such as supercritical CO2, demonstrate the formation of complex fracture networks spread throughout the rocks. To study the influence of viscosity of the fracturing fluids on hydraulic fracture propagation, a hydromechanical-coupled cohesive zone model is proposed for the simulation of mechanical response of rock grains boundary separation. This simulation methodology considers the synergistic effects of unsteady flow in fracture and rock grain deformation induced by hydraulic pressure. The simulation results indicate a tendency of complex fracture propagation with more branches as the viscosity of fracturing fluids decrease, which is in accord with experimental results. The low-viscosity fluid can flow into the microfractures with extremely small aperture and create more shear failed fracture. This study confirms the possibility of effective well stimulations by hydraulic fracturing with low-viscosity fluids.

Experiments on the breakup of drop-impact crowns by Marangoni holes

2018 ◽  
Vol 844 ◽  
pp. 162-186 ◽  
Author(s):  
Abdulrahman B. Aljedaani ◽  
Chunliang Wang ◽  
Aditya Jetly ◽  
S. T. Thoroddsen
Keyword(s):  
Surface Tension ◽  
Lower Surface ◽  
High Viscosity ◽  
Solid Substrate ◽  
Immiscible Liquid ◽  
Hole Formation ◽  
Low Viscosity ◽  
Stress Changes ◽  
Lower Surface Tension ◽  
The Impact

We investigate experimentally the breakup of the Edgerton crown due to Marangoni instability when a highly viscous drop impacts on a thin film of lower-viscosity liquid, which also has different surface tension than the drop liquid. The presence of this low-viscosity film modifies the boundary condition, giving effective slip to the drop along the solid substrate. This allows the high-viscosity drop to form a regular bowl-shaped crown, which rises vertically away from the solid and subsequently breaks up through the formation of a multitude of Marangoni holes. Previous experiments have proposed that the breakup of the crown results from a spray of fine droplets ejected from the thin low-viscosity film on the solid, e.g. Thoroddsen et al. (J. Fluid Mech., vol. 557, 2006, pp. 63–72). These droplets can hit the inner side of the crown forming spots with lower surface tension, which drives a thinning patch leading to the hole formation. We test the validity of this assumption with close-up imaging to identify individual spray droplets, to show how they hit the crown and their lower surface tension drive the hole formation. The experiments indicate that every Marangoni-driven patch/hole is promoted by the impact of such a microdroplet. Surprisingly, in experiments with pools of higher surface tension, we also see hole formation. Here the Marangoni stress changes direction and the hole formation looks qualitatively different, with holes and ruptures forming in a repeatable fashion at the centre of each spray droplet impact. Impacts onto films of the same liquid, or onto an immiscible liquid, do not in general form holes. We furthermore characterize the effects of drop viscosity and substrate-film thickness on the overall evolution of the crown. We also measure the three characteristic velocities associated with the hole formation: i.e. the Marangoni-driven growth of the thinning patches, the rupture speed of the resulting thin films inside these patches and finally the growth rate of the fully formed holes in the crown wall.

Is High Viscosity a Requirement for Fracturing Fluids?

2022 ◽  
Author(s):  
John E. Busteed ◽  
Jesus Arroyo ◽  
Francisco Morales ◽  
Mohammed Omer ◽  
Francisco E. Fragachan
Keyword(s):  
Injection Pressure ◽  
Fracture Network ◽  
High Viscosity ◽  
Network Simulator ◽  
Well Performance ◽  
Field Case ◽  
Temperature Conditions ◽  
Low Viscosity ◽  
Fracturing Fluids ◽  
Fracture Closure

Abstract Uniformly distributing proppant inside fractures with low damage on fracture conductivity is the most important index of successful fracturing fluids. However, due to very low proppant suspension capacity of slickwater and friction reducers fracturing fluids and longer fracture closure time in nano & pico darcies formations, proppants settles quickly and accumulates near wellbore resulting in worse-than-expected well performance, as the fracture full capacity is not open and contributing to production. Traditionally, cross-linked polymer fluid systems are capable to suspend and transport high loading of proppants into a hydraulically generated fracture. Nevertheless, amount of unbroken cross-linked polymers is usually left in fractures causing damage to fracture proppant conductivity, depending on polymer loading. To mitigate these challenges, a low viscosity-engineered-fluid with excellent proppantcarrying capacity and suspension-in excess of 30 hours at static formation temperature conditions - has been designed, enhancing proppant placement and distribution within developed fractures, with a 98% plus retained conductivity. In this work experimental and numerical tests are presented together with the path followed in developing a network of packed structures from polymer associations providing low viscosity and maximum proppant suspension. Challenges encountered during field injection with friction are discussed together with the problem understanding characterized via extensive friction loop tests. Suspension tests performed with up to 8-10 PPA of proppant concentration at temperature conditions are shared, together with slot tests performed. Physics-based model results from a 3D Discrete Fracture Network simulator that computes viscosity, and elastic parameters based on shear rate, allows to estimate pressure losses along the flow path from surface lines, tubular goods, perforations, and fracture. This work will demonstrate the advanced capabilities and performance of the engineered fluid over conventional fracturing fluids and its benefits. Additionally, this paper will present field injection pressure analysis performed during the development of this fluid, together with a field case including production results after 8 months of treatment. The field case production decline observed after fracture treatment demonstrates the value of this system in sustaining well production and adding additional reserves.

scholarly journals Methodological approach to optimal geological and technological characteristics determining when planning hydraulic fracturing at multilayer facilities

2021 ◽  
pp. 182-191
Author(s):  
V. A. Grishchenko ◽  
◽  
R. U. Rabaev ◽  
I. N. Asylgareev ◽  
V. Sh. Mukhametshin ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Methodological Approach ◽  
Oil Fields ◽  
Hydraulic Fractures ◽  
Reservoir Properties ◽  
Effective Power ◽  
Stage Of Development ◽  
Technological Characteristics ◽  
Specific Loading ◽  
Geological Conditions

The paper considers the issue of increasing the hydraulic fracturing efficiency in a multilayer facility at the final stage of development with an uneven degree of reserves development along the section. Based on the results of the analysis, it was found that the upper layers, which have the worst filtration-reservoir properties, are less developed in comparison with the highly productive lower ones. When hydraulic fracturing was carried out in the upper formations, some of the operations had low success due to the breakthrough of hydraulic fractures into the lower depleted formations. On the basis of the revealed dependencies, the work determined the optimal specific loading of proppant per meter of effective power, depending on the geological conditions, and maps of the prospects for hydraulic fracturing are built. Keywords: oil fields development; hydraulic fracturing; hydraulic fracturing optimization; multilayer facilities.

Deformation, heating and melting of solids in high-speed friction

1961 ◽  
Vol 260 (1303) ◽  
pp. 433-458 ◽  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Frictional Heating ◽  
Vertical Axis ◽  
High Viscosity ◽  
Molten Material ◽  
General Behaviour ◽  
Low Viscosity ◽  
Heavy Loads ◽  
The Impact

An experimental study has been made of the effects of frictional heating on the deformation of solids rubbing at very high speeds and at reasonably heavy loads. A new method for measuring the friction under these conditions is described. A steel ball, rapidly spinning round its vertical axis, is allowed to fall a short distance and to bounce off an inclined flat solid surface. The friction of steel on various solids in a vacuum of ca . 10 -4 mm Hg, at sliding speeds up to 700 m/s, is determined from the measured direction of the ball’s horizontal velocity after the impact. In addition, separate piezo-electric measurements are made of the load and the friction force. Again the coefficient of friction is found to decrease with increasing sliding speed. The general behaviour is similar to that observed at light loads but there are important differences. With heavy loads the deformation of the solids appears to be primarily plastic. Within a very short time after being brought into contact with a fast-moving surface, solids with a sufficiently low melting point melt on a large scale so that a continuous film of molten material is developed over the area of contact. The resistance to motion is determined primarily by this liquid film so that it may now increase as the speed rises. The heating due to the shearing of this film causes the solid to melt away rapidly, and as a result the wear rate of such solids usually becomes great at high sliding speeds. Certain polymers, however, exhibit a greater wear resistance than metals and other solids which possess a low viscosity in the molten state. Calculations indicate that in these polymers, owing to their high viscosity, the temperature of the sheared film may be considerably higher than the melting temperature. As a consequence, a larger proportion of the heat developed by the shearing may be absorbed in the already molten material, and less heat will be available for further melting. Gas liberated by thermal decomposition may also reduce the friction and wear.

scholarly journals Investigation of the Fracturing Effect Induced by the Disturbing Stress of Hydrofracturing Using the Bonded-Particle Model

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Xin Zhang ◽  
Yuqi Zhang ◽  
Bingxiang Huang
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Fracture Zone ◽  
Fracture Propagation ◽  
Bedding Plane ◽  
Particle Model ◽  
Hydraulic Fractures ◽  
Bedding Planes ◽  
Geological Conditions ◽  
Hydraulic Fracture Propagation

Hydraulic fracturing applications have shown a stress disturbance effect during hydraulic fracture propagation, which is often ignored. Using laboratory and discrete element numerical simulation tests, hydraulic fracture propagation under this stress disturbance is systematically studied. The results show that during hydraulic fracturing, the bedding plane is damaged by the stress disturbance, forming a bedding fracture zone (BFZ). The nonlinear fracture characteristics of the formation process of the disturbed fracture zone are revealed, and two indexes (the number of fractures in the disturbed fracture zone and the size of the disturbed fracture zone) are proposed to evaluate the fracturing effect of the stress disturbance. Based on these indexes, multifactor sensitivity tests are conducted under different geological conditions and operational factors. When the principal stress ( σ 1 ) difference is large, the number of hydraulic fractures gradually decreases from many to one, and the direction of the hydraulic fractures gradually approaches the vertical direction of σ 3 , but the change in the in situ stress condition has no obvious effect on the stress disturbance effect. The weaker the bonding strength of the bedding plane, the more significant the stress disturbance effect is, and the easier it is for the fractures to expand along the bedding plane. With increasing injection rate, the stress disturbance effect first increases and then decreases, and the hydraulic fracture propagates from along the bedding plane to cross the bedding plane. With increasing relative distance between the injection hole and bedding plane, the stress disturbance effect presents a linearly increasing trend, and the hydraulic fractures along the bedding planes extend. Based on the experimental results, the relationship between the fracturing effect of the stress disturbance and the extension mode of the hydraulic fracture is determined, and an optimization method for hydraulic fracturing in composite rock reservoirs is given. The research results can provide a theoretical basis for controlling the formation of complex fracture networks in composite rock reservoirs.

scholarly journals An Analytical Model for Fracture Initiation from a Particular Radial Borehole in Hydraulic Fracturing Guided by Multiradial Boreholes

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yuxin Chen ◽  
Yunhong Ding ◽  
Chong Liang ◽  
Dawei Zhu ◽  
Yu Bai ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Analytical Model ◽  
Fracture Initiation ◽  
Hydraulic Fractures ◽  
Large Radius ◽  
Intersection Angle ◽  
Biot Coefficient ◽  
Depth Difference ◽  
Wellbore Pressure ◽  
The Impact

Radial drilling-fracturing, the combination of the hydraulic fracturing and radial borehole, is a technology that can guide the hydraulic fractures to directionally propagate and efficiently develop low permeability reservoir. In this paper, an analytical model of two radial boreholes (a basic research unit) is established to predict fracture initiation pressure (FIP) from one particular radial borehole and the interference between radial boreholes when the hydraulic fracturing is guided by multi-radial boreholes. The model is based on the stress superposition principle and the maximum tensile stress criterion. The effects of in situ stress, wellbore pressure, and fracturing fluid percolation are considered. Then, sensitivity analysis is performed by examining the impact of the intersection angle between radial boreholes, the depth difference between radial boreholes, the radius of radial boreholes, Biot coefficient, and the number of radial boreholes. The results show that FIP declines with the increase of radial boreholes number and the decrease of intersection angle and depth difference between radial boreholes. Meanwhile, the increase of radial borehole number and the reduction of intersection angle and depth difference strengthen the interference between radial boreholes, which conduce to the formation of the fracture network connecting radial boreholes. Besides, FIP declines with the increase of radial borehole radius and the decrease of Biot coefficient. Large radius and low Biot coefficient can enlarge the influence range of additional stress field produced by radial boreholes, enhance the mutual interference between radial boreholes, and guide fracture growth between radial boreholes. In hydraulic fracturing design, in order to reduce FIP and strengthen the interference between radial boreholes, the optimization design can be carried out by lowering intersection angle, increasing radius and number of boreholes, and reducing the depth difference between boreholes when the conditions permit. The research clarifies the interference between radial boreholes and provides the theoretical basis for optimizing radial boreholes layout in hydraulic fracturing guided by multi-radial boreholes.

scholarly journals Advances in Laboratory-Scale Hydraulic Fracturing Experiments

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Yelin Qian ◽  
Panpan Guo ◽  
Yixian Wang ◽  
Yanlin Zhao ◽  
Hang Lin ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Laboratory Scale ◽  
Future Research ◽  
Accurate Estimation ◽  
Hydraulic Fractures ◽  
Scaling Analysis ◽  
Research Attention ◽  
Complete Control ◽  
Geological Conditions ◽  
Fracturing Experiments

Hydraulic fracturing has been widely applied to stimulate the natural gas and oil production from unconventional reservoirs. To optimize the design of hydraulic fracturing in this application, an accurate estimation of the initiation and propagation of hydraulic fractures is indispensable. However, it still remains challenging as a result of the complex stress state and geological conditions. On account of their ability to complete control some significant factors and efficient observation of fracture geometry, laboratory-scale hydraulic fracturing experiments have received abundant research attention in recent years. This paper presents a review of the state of the art of laboratory-scale hydraulic fracturing experiments, focusing on the scaling analysis, experimental setup, fracturing fluids, and sample preparation. A discussion of the directions for future research is also provided with the intention of stimulating the development of the experimental technique for investigating hydraulic fracturing.

scholarly journals Analysis Study Of The Effect In Selecting Combination Of Fracturing Fluid Types And Proppant Sizes On Folds Of Increase (FOI) To Improve Well Productivity

2020 ◽  
Vol 1 (2) ◽  
pp. 92
Author(s):  
Dimas Ramadhan ◽  
Hidayat Tulloh ◽  
Cahyadi Julianto
Keyword(s):  
Hydraulic Fracturing ◽  
High Viscosity ◽  
Test Method ◽  
Fracturing Fluid ◽  
Fracturing Fluids ◽  
Lower Viscosity ◽  
Pump Rate ◽  
Fracturing Process ◽  
Fractured Well ◽  
Selection Of

As fracturing materials, fracturing fluid and proppant are two very important parameters in doing hydraulic fracturing design. The combination of fractuirng fluid and proppant selection is the main focus and determinant of success in the hydraulic fracturing process. The high viscosity of the fracturing fluid will make it easier for the proppant to enter to fill the fractured parts, so that the conductivity of the fractured well will be better and can increase the folds of increase (FOI) compared to fracturing fluid with lower viscosity (Economides, 2000). This research was conducted by using the sensitivity test method on the selection of fracturing fluid combinations carried out at the TX-01 well with various sizes of proppants (namely; 12/18, 16/20, and 20/40 mesh) with the proppant selected being ceramic proppant type carbolite performed using the FracCADE simulator. Fracturing fluid was selected based on its viscosity, namely YF240OD and PrimeFRAC20 fluids with viscosity value of 4.123 cp and 171.1 cp, with a fixed pump rate of 14 bpm. The results showed that the combination of high-viscosity fluids (PrimeFRAC20) and 16/20 mesh proppant size resulted in a greater incremental fold (FOI) between the choice of another combination fracturing fluids and proppant sizes, namely 6.25.

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