Experimental Investigation of Fracturing-Fluid Migration Caused by Spontaneous Imbibition in Fractured Low-Permeability Sands

2014 ◽  
Vol 17 (01) ◽  
pp. 74-81 ◽  
Author(s):  
R.. Dutta ◽  
C.-H.. -H. Lee ◽  
S.. Odumabo ◽  
P.. Ye ◽  
S.C.. C. Walker ◽  
...  
Keyword(s):  
Capillary Forces ◽  
Spontaneous Imbibition ◽  
Low Permeability ◽  
Driving Mechanism ◽  
Fluid Migration ◽  
High Permeability ◽  
Fracturing Fluid ◽  
X Ray ◽  
Fracturing Fluids ◽  
Water Based

Summary During hydraulic-fracturing operations in low-permeability formations, spontaneous imbibition of fracturing fluid into the rock matrix is believed to have a significant impact on the retention of water-based fracturing fluids in the neighborhood of the induced fracture. This may affect the post-fracturing productivity of the well. However, there is lack of direct experimental and visual evidence of the extent of fluid retention, evolution of the resulting imbibing-fluid front, and how they relate to potential productivity hindrance. In this paper, laboratory experiments have been carefully designed to represent the vicinity of a hydraulic fracture. The evolution of fracturing fluid leakoff is monitored as a function of space and time by use of X-ray computed tomography (CT). The X-ray CT imaging technique allows us to map saturations at controlled time intervals to monitor the migration of fracturing fluid into the reservoir formation. It is generally expected for low-permeability formations (5 to 10 md) to show strong capillary forces because of their small characteristic pore radii, but this driving mechanism is in competition with the low permeability and spatial heterogeneities found in low-permeability sands. The relevance of capillarity as a driver of fluid migration and retention in a low-permeability sand sample is interpreted visually and quantified and compared with high-permeability Berea sandstone in our experiments. It is seen that although low-permeability sands are subject to strong capillary forces, the effect can be suppressed by the low permeability of the formation and the heterogeneous nature of the sample. Nevertheless, saturation values attained as a result of spontaneous imbibition are comparable with those obtained for high-permeability samples. Leakoff of fracturing fluids during the shut-in period of a well can result in delayed gas flowback and can hinder gas production. Results from this investigation are expected to provide fundamental insight regarding critical variables affecting the retention and migration of water-based fracturing fluids in the neighborhood of hydraulic fractures, and consequently affecting the post-fracturing productivity of the well.

Leak-Off Coefficient Analysis in Stimulation Treatment Design

2014 ◽  
Vol 933 ◽  
pp. 202-205
Author(s):  
Bo Cai ◽  
Yun Hong Ding ◽  
Yong Jun Lu ◽  
Chun Ming He ◽  
Gui Fu Duan
Keyword(s):  
Hydraulic Fracturing ◽  
Field Method ◽  
Oil Field ◽  
Low Permeability ◽  
Analysis Model ◽  
Fracturing Fluid ◽  
Real Time Analysis ◽  
Fracturing Fluids ◽  
Common Technique ◽  
Treatment Design

Hydraulic fracturing was first used in the late 1940s and has become a common technique to enhance the production of low-permeability formations.Hydraulic fracturing treatments were pumped into permeable formations with permeable fluids. This means that as the fracturing fluid was being pumped into the formation, a certain proportion of this fluid will being lost into formation as fluid leak-off. Therefore, leak-off coefficient is the most leading parameters of fracturing fluids. The accurate understanding of leak-off coefficient of fracturing fluid is an important guidance to hydraulic fracturing industry design. In this paper, a new field method of leak-off coefficient real time analysis model was presented based on instantaneous shut-in pressure (ISIP). More than 100 wells were fractured using this method in oil field. The results show that average liquid rates of post-fracturing was 22m3/d which double improvement compared with the past treatment wells. It had an important role for hydraulic fracturing stimulation treatment design in low permeability reservoirs and was proven that the new model for hydraulic fracturing treatment is greatly improved.

scholarly journals Modeling Hydraulic Fracturing Using Natural Gas Foam as Fracturing Fluids

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7645
Author(s):  
Shuang Zheng ◽  
Mukul M. Sharma
Keyword(s):  
Equation Of State ◽  
Natural Gas ◽  
Hydraulic Fracturing ◽  
Gas Emission ◽  
Fracturing Fluid ◽  
Fracturing Fluids ◽  
Water Based ◽  
Simulation Results ◽  
The Cost ◽  
Stranded Gas

Stranded gas emission from the field production because of the limitations in the pipeline infrastructure has become one of the major contributors to the greenhouse effects. How to handle the stranded gas is a troublesome problem under the background of global “net-zero” emission efforts. On the other hand, the cost of water for hydraulic fracturing is high and water is not accessible in some areas. The idea of using stranded gas in replace of the water-based fracturing fluid can reduce the gas emission and the cost. This paper presents some novel numerical studies on the feasibility of using stranded natural gas as fracturing fluids. Differences in the fracture creating, proppant placement, and oil/gas/water flowback are compared between natural gas fracturing fluids and water-based fracturing fluids. A fully integrated equation of state compositional hydraulic fracturing and reservoir simulator is used in this paper. Public datasets for the Permian Basin rock and fluid properties and natural gas foam properties are collected to set up simulation cases. The reservoir hydrocarbon fluid and natural gas fracturing fluids phase behavior is modeled using the Peng-Robinson equation of state. The evolving of created fracture geometry, conductivity and flowback performance during the lifecycle of the well (injection, shut-in, and production) are analyzed for the gas and water fracturing fluids. Simulation results show that natural gas and foam fracturing fluids are better than water-based fracturing fluids in terms of lower breakdown pressure, lower water leakoff into the reservoir, and higher cluster efficiency. NG foams tend to create better propped fractures with shorter length and larger width, because of their high viscosity. NG foam is also found to create better stimulated rock volume (SRV) permeability, better fracturing fluid flowback with a large water usage reduction, and high natural gas consumption. The simulation results presented in this paper are helpful to the operators in reducing natural gas emission while reducing the cost of hydraulic fracturing operation.

scholarly journals FORMATION HYDRAULIC FRACTURING FLUID BASED ON CARBOXYMETHYL CELLULOSE: ITS ADVANTAGES AND LIMITATIONS, APPLICATION PROSPECTS

2016 ◽  
pp. 49-57
Author(s):  
V. R. Kalinin
Keyword(s):  
Hydraulic Fracturing ◽  
Carboxymethyl Cellulose ◽  
Low Cost ◽  
Low Permeability ◽  
Laboratory Studies ◽  
Fracturing Fluid ◽  
Fracturing Fluids ◽  
Low Permeability Reservoirs ◽  
Manufacturing Features ◽  
Hydraulic Fracturing Fluid

The article considers the advantages and limitations of hydraulic fracturing fluid based on carboxymethyl cellulose determined as a result of laboratory studies. As a result of testing the studied fluid manufacturing features compared with similar fracturing fluids it was determined that the fluid of interest can be effectively used as a fluid for formation hydraulic fracturing especially in low permeability reservoirs. This fluid is widely available and has a low cost. It can easily replace the foreign analogues.

scholarly journals Experimental and Simulation Studies of Energized Fracturing Fluid Efficiency in Tight Gas Formations

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4465
Author(s):  
Klaudia Wilk
Keyword(s):  
Clay Minerals ◽  
Guar Gum ◽  
Laboratory Data ◽  
Good Alternative ◽  
Rheological Parameters ◽  
Fracturing Fluid ◽  
Additional Energy ◽  
Negative Results ◽  
Fracturing Fluids ◽  
Water Based

The use of water-based fracturing fluids during fracturing treatment can be a problem in water-sensitive formations due to the permeability damage hazard caused by clay minerals swelling. The article includes laboratory tests, analyses and simulations for nitrogen foamed fracturing fluids. The rheology and filtration coefficients of foamed fracturing fluids were examined and compared to the properties of conventional water-based fracturing fluid. Laboratory results provided the input for numerical simulation of the fractures geometry for water-based fracturing fluids and 50% N2 foamed fluids, with addition of natural, fast hydrating guar gum. The results show that the foamed fluids were able to create shorter and thinner fractures compared to the fractures induced by the non-foamed fluid. The simulation proved that the concentration of proppant in the fracture and its conductivity are similar or slightly higher when using the foamed fluid. The foamed fluids, when injected to the reservoir, provide additional energy that allows for more effective flowback, and maintain the proper fracture geometry and proppant placing. The results of laboratory work in combination with the 3D simulation showed that the foamed fluids have suitable viscosity which allows opening the fracture, and transport the proppant into the fracture, providing successful fracturing operation. The analysis of laboratory data and the performed computer simulations indicated that fracturing fluids foamed by nitrogen are a good alternative to non-foamed fluids. The N2-foamed fluids exhibit good rheological parameters and proppant-carrying capacity. Simulated fracture of water-based fracturing fluid is slightly longer and higher compared to foamed fluid. At the same time, when using a fluid with a gas additive, the water content in fracturing fluid is reduced which means the minimization of the negative results of the clay minerals swelling.

scholarly journals Mathematical Model for the Fluid-Gas Spontaneous Displacement in Nanoscale Porous Media considering the Slippage and Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kang Liu ◽  
Zhongyue Lin ◽  
Daiyong Cao ◽  
Yingchun Wei
Keyword(s):  
Porous Media ◽  
Fluid Transport ◽  
Slip Length ◽  
Gas Production ◽  
Spontaneous Imbibition ◽  
Experimental Result ◽  
Fracturing Fluid ◽  
Fracturing Fluids ◽  
Fracturing Process ◽  
Displacement Model

The fracturing fluid-gas spontaneous displacement during the fracturing process is important to investigate the shale gas production and formation damage. Temperature and slippage are the major mechanisms underlying fluid transport in the micro-/nanomatrix in shale, as reported in the previous studies. We built a fracturing fluid-gas spontaneous displacement model for the porous media with micro-/nanopores, considering two major mechanisms. Then, our spontaneous displacement model was verified by the experimental result of the typical shale samples and fracturing fluids. Finally, the influences of temperature, slip length, and pore size distribution on the spontaneous imbibition process were discussed. Slippage and temperature significantly influenced the imbibition process. Lower viscosity, higher temperature, and longer slip length increased the imbibition speed. Ignoring the temperature change and slippage will lead to significant underestimation of the imbibition process.

Improved Gelation Performance of an Acidic Low-Polymer Loading Zirconium Cross-Linked CMHPG Fracturing Fluid by Surface Functionalized 1T-Phase Molybdenum Disulfide Nanosheets

2021 ◽  
Author(s):  
Kaiyu Zhang ◽  
Jirui Hou ◽  
Zhuojing Li
Keyword(s):  
Electron Microscopy ◽  
Molybdenum Disulfide ◽  
Guar Gum ◽  
Mos2 Nanosheets ◽  
Fracturing Fluid ◽  
X Ray ◽  
Hydroxypropyl Guar ◽  
Fracturing Fluids ◽  
Cross Linker ◽  
Hydroxypropyl Guar Gum

Abstract The low and ultra-low permeability reservoirs in China, such as the Changqing, Jidong, and Daqing peripheral oil fields, often apply CO2 as a flooding medium to enhance oil recovery. A serial of water-rock interactions will be occurred among the CO2, formation rock, and formation water under the HT/HP conditions. The pH value of the formation will be converted to acidity accordingly. As a side effect, the traditional guar-based fracturing fluids in an alkaline range, such as the borate cross-linked hydroxypropyl guar gum (HPG), cannot result in an effective hydrofracturing operation due to the incompatibility. Consequently, developing an acidic fracturing fluid system with a satisfactory performance is an imperative. Acidic fracturing fluids, such as the zirconium cross-linked carboxymethyl hydroxypropyl guar gum (CMHPG), can protect the formation during the hydrofracturing process from the damage arising from the swelling and migration of the clay particles. However, the shortcomings of the uncontrollable viscosity growth and the irreversible shear-thinning behavior limit the large-scale use of the acidic fracturing fluids. In this work, a novel organic zirconium cross-linker synthesized in the laboratory was applied to control and delay the cross-link reaction under the acidic condition. The ligands coordinated to the zirconium center were the L-lactate and ethylene glycol. The thickener used was the CMHPG at a low loading of 0.3% (approximately 25 pptg). Meanwhile, the surface functionalized metallic phase (1T-phase) molybdenum disulfide (MoS2) nanosheets were employed to improve the rheological performance of the zirconium cross-linked CMHPG fracturing fluid. The modification reagent utilized was the L-cysteine. The morphology, structure, and property of the fabricated functionalized 1T-MoS2 (Cys-1T-MoS2) nanosheets were systematically characterized using the transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) measurements. The results of the characterization tests demonstrated a successful functionalization of the 1T-MoS2 nanosheets with L-cysteine. Then, the effects of this new nanosheet-enhanced zirconium cross-linked CMHPG fracturing fluid systems with different cross-linker and nanosheet loadings on gelation performance were systematically assessed employing the Sydansk bottle testing method combined with a rheometer under the controlled-stress or controlled-rate modes. The results indicated that the nanosheet-enhanced fracturing fluid had a desirable delayed property. Compared with the blank fracturing fluid (without nanosheets), the nanosheet-enhanced fracturing fluid had a much better shear-tolerant and shear-recovery performance.

Quantification of Fracturing Fluid Migration due to Spontaneous Imbibition in Fractured Tight Formations

2012 ◽  
Author(s):  
Riteja Dutta ◽  
Chung-hao Lee ◽  
Sijuola Odumabo ◽  
Peng Ye ◽  
Stacey C. Walker ◽  
...  
Keyword(s):  
Spontaneous Imbibition ◽  
Fluid Migration ◽  
Fracturing Fluid ◽  
Tight Formations

scholarly journals Design of facile technology for the efficient removal of hydroxypropyl guar gum from fracturing fluid

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247948
Author(s):  
Shiliang Xu ◽  
Mengke Cui ◽  
Renjie Chen ◽  
Qiaoqing Qiu ◽  
Jiacai Xie ◽  
...  
Keyword(s):  
Guar Gum ◽  
Low Cost ◽  
High Viscosity ◽  
Fracturing Fluid ◽  
X Ray ◽  
Practical Applications ◽  
Hydroxypropyl Guar ◽  
Fracturing Fluids ◽  
Removal Technologies ◽  
Hydroxypropyl Guar Gum

With the increasing demand for energy, fracturing technology is widely used in oilfield operations over the last decades. Typically, fracturing fluids contain various additives such as cross linkers, thickeners and proppants, and so forth, which makes it possess the properties of considerably complicated components and difficult processing procedure. There are still some difficult points needing to be explored and resolved in the hydroxypropyl guar gum (HPG) removal process, e.g., high viscosity and removal of macromolecular organic compounds. Our works provided a facile and economical HPG removal technology for fracturing fluids by designing a series of processes including gel-breaking, coagulation and precipitation according to the diffusion double layer theory. After this treatment process, the fracturing fluid can meet the requirements of reinjection, and the whole process was environment friendly without secondary pollution characteristics. In this work, the fracturing fluid were characterized by scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy technologies, etc. Further, the micro-stabilization and destabilization mechanisms of HPG in fracturing fluid were carefully investigated. This study maybe opens up new perspective for HPG removal technologies, exhibiting a low cost and strong applicability in both fundamental research and practical applications.

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