scholarly journals Comparative Studies on Hydraulic Fracturing Fluids for High-Temperature and High-Salt Oil Reservoirs: Synthetic Polymer versus Guar Gum

ACS Omega ◽  
2021 ◽  
Author(s):  
Xiaoqin Cao ◽  
Yiwen Shi ◽  
Wenzhi Li ◽  
Peiyun Zeng ◽  
Zhuo Zheng ◽  
...  
Keyword(s):  
High Temperature ◽  
Hydraulic Fracturing ◽  
Comparative Studies ◽  
Guar Gum ◽  
Synthetic Polymer ◽  
High Salt ◽  
Oil Reservoirs ◽  
Fracturing Fluids

scholarly journals Laboratory Testing of Fracture Conductivity Damage by Foam-Based Fracturing Fluids in Low Permeability Tight Gas Formations

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1783
Author(s):  
Klaudia Wilk-Zajdel ◽  
Piotr Kasza ◽  
Mateusz Masłowski
Keyword(s):  
Hydraulic Fracturing ◽  
Guar Gum ◽  
Polymer Concentration ◽  
Laboratory Research ◽  
Damage Effect ◽  
Tight Gas ◽  
Fracturing Fluid ◽  
Fracture Conductivity ◽  
Fracturing Fluids ◽  
Sandstone Rock

In the case of fracturing of the reservoirs using fracturing fluids, the size of damage to the proppant conductivity caused by treatment fluids is significant, which greatly influence the effective execution of hydraulic fracturing operations. The fracturing fluid should be characterized by the minimum damage to the conductivity of a fracture filled with proppant. A laboratory research procedure has been developed to study the damage effect caused by foamed and non-foamed fracturing fluids in the fractures filled with proppant material. The paper discusses the results for high quality foamed guar-based linear gels, which is an innovative aspect of the work compared to the non-foamed frac described in most of the studies and simulations. The tests were performed for the fracturing fluid based on a linear polymer (HPG—hydroxypropyl guar, in liquid and powder form). The rheology of nitrogen foamed-based fracturing fluids (FF) with a quality of 70% was investigated. The quartz sand and ceramic light proppant LCP proppant was placed between two Ohio sandstone rock slabs and subjected to a given compressive stress of 4000–6000 psi, at a temperature of 60 °C for 5 h. A significant reduction in damage to the quartz proppant was observed for the foamed fluid compared to that damaged by the 7.5 L/m3 natural polymer-based non-foamed linear fluid. The damage was 72.3% for the non-foamed fluid and 31.5% for the 70% foamed fluid, which are superior to the guar gum non-foamed fracturing fluid system. For tests based on a polymer concentration of 4.88 g/L, the damage to the fracture conductivity by the non-foamed fluid was 64.8%, and 26.3% for the foamed fluid. These results lead to the conclusion that foamed fluids could damage the fracture filled with proppant much less during hydraulic fracturing treatment. At the same time, when using foamed fluids, the viscosity coefficient increases a few times compared to the use of non-foamed fluids, which is necessary for proppant carrying capacities and properly conducted stimulation treatment. The research results can be beneficial for optimizing the type and performance of fracturing fluid for hydraulic fracturing in tight gas formations.

Poly(oxyalkylene) grafts to guar gum with applications in hydraulic fracturing fluids

2006 ◽  
Vol 17 (9-10) ◽  
pp. 679-681 ◽  
Author(s):  
Ahmad Bahamdan ◽  
William H. Daly
Keyword(s):  
Hydraulic Fracturing ◽  
Guar Gum ◽  
Fracturing Fluids

Chemically Modified Natural Gum for Use in Well Stimulation

1977 ◽  
Vol 17 (01) ◽  
pp. 5-10 ◽  
Author(s):  
C.J. Githens ◽  
J.W. Burnham
Keyword(s):  
Hydraulic Fracturing ◽  
Apparent Viscosity ◽  
Guar Gum ◽  
Gelling Agent ◽  
Polymer Emulsion ◽  
Gelling Agents ◽  
Chemically Modified ◽  
Well Stimulation ◽  
Fracturing Fluids ◽  
New Material

Abstract A new polymer gelling agent has been developed to help satisfy the growing demand for "clean" hydraulic fracturing fluids. This polymer is a guar derivative that exhibits the desirable characteristics of conventional guar and that leaves low residue upon breaking. The derivatized guar was evaluated for its ability to function as a fracturing-fluid gelling agent in comparison with both a conventional guar and a nonionic cellulose derivative. The guar derivative possesses a number of advantages over both the conventional guar and the cellulose derivative. Laboratory experimental data and field results are presented. Introduction Hydraulic fracturing has been used successfully for oil- and gas-well stimulation for about 27 years. During this time the size of the treatments has grown from the original "tank of oil and sack of sand" to the current massive hydraulic fracturing treatments, entailing several hundred thousand gallons of fluid and large amounts of sand. These massive treatments have become routine in some areas of this country. Although many types of fluids have been used successfully, aqueous fluids have been preferred recently. Because of economic and safety considerations, aqueous fluids will likely continue to be preferred. Treatment designs usually require that the fluids possess a particular apparent viscosity. These stipulated viscosities are particular apparent viscosity. These stipulated viscosities are often many times higher than that of the base fluid in its natural state. The increased apparent viscosities are generally attained by the addition of hydrophilic polymeric "gelling agents." A variety of gelling agents for aqueous fluids is available. Each gelling agent possesses inherent chemical properties that often make it particularly applicable for a special function. These properties are a direct result of the chemical structure and stereochemistry of the repeating unit of the polymer, and the resulting conformation or macrostructure that the polymer assumes in the fluid. Polysaccharides, such as the guar polymer, possess many of the properties desired of a gelling agent. However, the relatively high percentage of insolubles (residue) present in commercial guar has been a matter of serious concern. Many believe that guar-gum residue can contribute to permanent formation and fracture conductivity damage. Because of the complexity of the situation, experimental evaluation of the over-all effect of this residue on the formation permeability and fracture flow capacity is difficult. However, there should be no question that the presence of the residue could result in damage to the formation and the proppant system, and that a reduction in the amount of residue proppant system, and that a reduction in the amount of residue present diminishes this possibility. present diminishes this possibility. A new low-residue, derivatized-guar (derivatized polysaccharide) gelling agent has been developed. This chemically polysaccharide) gelling agent has been developed. This chemically modified guar results in an 85-percent reduction in inherent residue over conventional guar gum, yet retains the desirable properties of the guar polymer. In addition, it provides an properties of the guar polymer. In addition, it provides an extension of guar chemistry and versatility into several new approaches for designing hydraulic fracturing fluids. This versatile polymer has application in most aqueous and polymer-emulsion hydraulic fracturing processes. polymer-emulsion hydraulic fracturing processes. In addition to possessing the obvious advantage of low residue, this new material can be dispersed controllably in aqueous fluids, thereby effectively reducing gel lumping tendencies. The result is a smooth, lump-free gel. It yields equivalent or slightly higher apparent viscosity values in fresh water and the usual brines compared with the old, conventional, guar-gum gelling agents. Alcohol tolerance of this new material is good, and it is readily complexed or crosslinked in water or alcohol-water mixtures with crosslinking agents. Fluids prepared with this new polymer may be manipulated to achieve temperature stability surpassing that of any gelled-water fracturing fluid containing the polysaccharides we have used in the past. SPEJ P. 5

Improve the Temperature Resistance of Guar Gum by Silanization

2011 ◽  
Vol 415-417 ◽  
pp. 652-655
Author(s):  
Jie Zhang ◽  
Gang Chen
Keyword(s):  
High Temperature ◽  
Reaction Time ◽  
Hydraulic Fracturing ◽  
Reaction Temperature ◽  
Guar Gum ◽  
Molar Ratio ◽  
Fracturing Fluid ◽  
Reaction Conditions ◽  
Temperature Resistance ◽  
Optimized Conditions

For gelating agent in hydraulic fracturing fluid, the temperature resistance is required. To improve the temperature resistance of Guar gum (GG), it was modified by silanization. The reaction conditions were investigated, and the optimized conditions were as following: the reaction temperature of 85°C, 5: 1 molar ratio of guar gum to TMS-Cl and 4-6 h of reaction time. The viscosity of silanized guar gum (SGG) aqueous gel was greatly improved even high temperature at 80°C.

scholarly journals A Novel Hydraulic Fracturing Method Based on the Coupled CFD-DEM Numerical Simulation Study

2020 ◽  
Vol 10 (9) ◽  
pp. 3027
Author(s):  
Cong Lu ◽  
Li Ma ◽  
Zhili Li ◽  
Fenglan Huang ◽  
Chuhao Huang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Hydraulic Fracturing ◽  
Variable Viscosity ◽  
Oil Reservoirs ◽  
Fluid Viscosity ◽  
Low Density ◽  
Fracturing Fluid ◽  
Proppant Transport ◽  
Fracturing Fluids ◽  
Transport Experiment

For the development of tight oil reservoirs, hydraulic fracturing employing variable fluid viscosity and proppant density is essential for addressing the problems of uneven placement of proppants in fractures and low propping efficiency. However, the influence mechanisms of fracturing fluid viscosity and proppant density on proppant transport in fractures remain unclear. Based on computational fluid dynamics (CFD) and the discrete element method (DEM), a proppant transport model with fluid–particle two-phase coupling is established in this study. In addition, a novel large-scale visual fracture simulation device was developed to realize the online visual monitoring of proppant transport, and a proppant transport experiment under the condition of variable viscosity fracturing fluid and proppant density was conducted. By comparing the experimental results and the numerical simulation results, the accuracy of the proppant transport numerical model was verified. Subsequently, through a proppant transport numerical simulation, the effects of fracturing fluid viscosity and proppant density on proppant transport were analyzed. The results show that as the viscosity of the fracturing fluid increases, the length of the “no proppant zone” at the front end of the fracture increases, and proppant particles can be transported further. When alternately injecting fracturing fluids of different viscosities, the viscosity ratio of the fracturing fluids should be adjusted between 2 and 5 to form optimal proppant placement. During the process of variable proppant density fracturing, when high-density proppant was pumped after low-density proppant, proppants of different densities laid fractures evenly and vertically. Conversely, when low-density proppant was pumped after high-density proppant, the low-density proppant could be transported farther into the fracture to form a longer sandbank. Based on the abovementioned observations, a novel hydraulic fracturing method is proposed to optimize the placement of proppants in fractures by adjusting the fracturing fluid viscosity and proppant density. This method has been successfully applied to more than 10 oil wells of the Bohai Bay Basin in Eastern China, and the average daily oil production per well increased by 7.4 t, significantly improving the functioning of fracturing. The proppant settlement and transport laws of proppant in fractures during variable viscosity and density fracturing can be efficiently revealed through a visualized proppant transport experiment and numerical simulation study. The novel fracturing method proposed in this study can significantly improve the hydraulic fracturing effect in tight oil reservoirs.

Mechanism and Prevention Method of Producing Hydrogen Sulfide in High Temperature Hydraulic Fracturing Well

2021 ◽  
Author(s):  
Zebo Yuan ◽  
Xiaoqiang Wang ◽  
Lizhi Zhou ◽  
Huifeng Liu ◽  
Xu Li ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
High Temperature ◽  
Hydraulic Fracturing ◽  
Sodium Thiosulfate ◽  
Ammonium Persulfate ◽  
Gas Reservoir ◽  
Fracturing Fluids ◽  
Series Of Experiments ◽  
Prevention Method ◽  
Fractured Well

Abstract For a successful hydraulic fracturing operation, shear recovery and thermal stability are critical in terms of successful fracture creation and proppant placement. Sodium thiosulfate is one of the most commonly used gel stabilizers in fracturing gel. This paper reported a well in sulfur-free gas reservoir produced hydrogen sulfide as much as 20000ppm after hydraulic fracturing operation. A series of experiments were carried out to reveal the mechanism of hydrogen sulfide production. Results showed that in solution with PH less than 6.5, when the temperature is higher than 119 degrees Celsius, sodium thiosulfate will react with hydrogen ions to generate hydrogen sulfide. In this complex reaction, there is also precipitation of elemental sulfur, which may block the pores of the reservoir and thence counteract the effect of hydraulic fracturing. The acidic solution in a fractured well is from (1) Spent acid left downhole due to pre-acid used to reduce fracturing pressure, and (2) Sulfuric acid produced by the decomposition of ammonium persulfate which is used as gel breaker at high temperature. This paper proposed two solutions to the problem of high-temperature fracturing fluids,one is to use a sulfur-free temperature stabilizer,and the other is to create a non-acid downhole environment. The opinions provided by this paper can help the operators reduce the risk of the damage of hydrogen sulfide and protect the integrity of the well of high temperature fracturing wells.

scholarly journals New insights into hydraulic fracturing fluids used for high-temperature wells

Petroleum ◽  
2020 ◽  
Author(s):  
Tariq Almubarak ◽  
Leiming Li ◽  
Jun Hong Ng ◽  
Hisham Nasr-El-Din ◽  
Mohammed AlKhaldi
Keyword(s):  
High Temperature ◽  
Hydraulic Fracturing ◽  
Fracturing Fluids

scholarly journals Research Progress of High Temperature Resistant Fracturing Fluid System

2021 ◽  
Vol 2076 (1) ◽  
pp. 012039
Author(s):  
Ke Xu ◽  
Yongjun Lu ◽  
Jin Chang ◽  
Yang Li
Keyword(s):  
High Temperature ◽  
Oil And Gas ◽  
Guar Gum ◽  
Crosslinking Agent ◽  
Research Progress ◽  
Fracturing Fluid ◽  
Fluid System ◽  
Fracturing Fluids ◽  
Ultra High Temperature ◽  
Exploration And Development

Abstract China has made significant progress in the efficient exploration and development of deep-seated oil and gas wells. Reservoir reformation, as the core tool of high-temperature deep-seated exploration and development, puts forward a strong demand for fracturing fluids. The ultra-high temperature fracturing fluid system developed in my country is mainly divided into two types: ultra-high temperature guar gum fracturing fluid and ultra-high temperature synthetic polyacrylamide fracturing fluid. The high temperature resistant fracturing fluid system is mainly composed of high temperature resistant thickener, high temperature resistant crosslinking agent and temperature stabilizing additives and other additives. Based on indoor research and a large amount of literature, this article summarizes the research and application of high temperature resistant fracturing fluid system, high temperature resistant thickener, high temperature resistant crosslinking agent and temperature stabilizing additives in my country in recent years, and pointed out the shortcomings and limitations of the high-temperature fracturing fluid, the technical direction of the development of high-temperature resistant fracturing fluid technology is proposed.

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