A Low-Viscosity Retarded Acid System for Stimulation of High-Temperature Deep Wells

Author(s):  
Mohammed Sayed ◽  
Amy J. Cairns ◽  
Bashayer S. Aldakkan ◽  
Ahmed M. Gomaa ◽  
Khalid R. Alnoaimi



2021 ◽  
Vol 687 (1) ◽  
pp. 012148
Author(s):  
Qiao Xin ◽  
Luo Pandeng ◽  
Qu Zhanqing ◽  
Guo Tiankui


Author(s):  
Peerzada Mosir Shah ◽  
Mohammad Shafi Mir

The purpose of this study aims at investigating the impact of multi-walled carbon nanotubes (MWCNT’s) on the properties of low viscosity grade asphalt binder. Asphalt binder with viscosity grade-10 is selected as the control binder and later it is modified with different percentages of MWCNT’s (0.5–2.5%). Penetration, softening point, ductility and rotational viscosity test were employed for evaluating the effect of MWCNT’s on basic physical properties of modified asphalt binder. Dynamic Shear Rheometer (DSR) is used for evaluating the rheological properties of the base and modified bitumen, for both aged and unaged bitumen. Based on the conventional and basic rheological tests, it was seen that the addition of MWCNT’s improved the high-temperature performance of modified bitumen. Multiple Stress Creep and Recovery (MSCR) test results revealed that the addition of MWCNT’s improved the creep and recovery of modified binders for both stress intensities (0.1 kPa and 3.2 kPa) which confirms that the modified binder is more rut resistant. Moreover, it was observed that there was a significant improvement in the aging resistance of the asphalt binder due to addition of MWCNTs. However low temperature performance of MWCNTs was not encouraging. Also, MWCNTs addition to asphalt binder was found to be stable under high-temperature storage condition. Overall, there is a significant amount of improvement using MWCNTs in the base asphalt binder.



2021 ◽  
Vol 6 (3(62)) ◽  
pp. 11-14
Author(s):  
Oleh Zimin

The object of research in this work is the intensification of hydrocarbon production. The most problematic task of the study is the efficiency of intensification of compacted high-temperature carbonate reservoirs. Despite the gradual transition to renewable energy sources, natural gas and oil will play a dominant role in the world's energy balance in the next 20–30 years. Carbonate rocks have significant mining potential, but low filtration properties require intensification to improve reservoir permeability. High temperatures and pressures at great depths require the improvement of existing hydrocarbon production technologies. The most popular method for treating reservoirs containing carbonates is acid treatments in different variations, but for effective treatment it is necessary to achieve deep penetration of the solution into the formation. The study solves the problem of selection of effective carrier liquids for the preparation of acid solutions for the treatment of compacted high-temperature reservoirs with high carbonate content. To ensure quality treatment, acid solutions must have low viscosity and surface tension coefficient, low reaction rate, their chemical properties must ensure the absence of insoluble precipitates in the process of reactions with fluids and rocks, as well as be environmentally friendly. To select the most optimal carrier liquid, experiments were conducted to determine which candidate liquids provide the minimum reaction rate of acidic solutions with carbonates. Based on the analysis of industrial application data and literature sources, water, nephras, methanol, ethyl acetate, and methyl acetate were selected for further research. Widely studied acetic acid was chosen as the basic acid. Studies have shown that methyl acetate has a number of advantages, namely low reaction rate, low viscosity and surface tension coefficient. As well as the possibility of hydrolysis in the formation with the release of acetic acid, which significantly prolongs the reaction time of the solution with the rock and the depth of penetration of the active solution into the formation.



2002 ◽  
Vol 66 (2) ◽  
pp. 253-259 ◽  
Author(s):  
K. A. Rodgers ◽  
R. Greatrex ◽  
M. Hyland ◽  
S. F. Simmons ◽  
P. R. L. Browne

AbstractTeruggite is the dominant phase in a soft, off-white, poorly-layered and weakly-cemented surface crust, 10–15 mm thick, occurring in the high-temperature El Tatio geothermal field of Chile. Other minerals present include halite, which is present throughout but also forms a thin (<0.5 mm), brittle, cratered surface to the deposit, nobleite, ulexite and opal-A, with possible traces of illite-smectite and at least one unidentified phase. With the exception of ulexite, none of the minerals associated with teruggite at El Tatio has been reported from other occurrences of this mineral, nor do they occur with nobleite in its sole other known occurrence in Death Valley. EDS and XPS analyses of the main mass of the deposit show the presence of Ca, As, B, Na, and Cl, consistent with the identified mineral assemblage, but with elevated concentrations in Ca and Cl that are presumably associated with a further phase. Little Mg is present and the El Tatio teruggite appears deficient in this element, with Ca presumably replacing Mg in the structure. Unlike earlier documented occurrences of teruggite, that at El Tatio is evaporitic, modern and surficial. It is located some 50 m from the nearest hot (~50°C) pool and there is no evidence of association with fluid discharge. As such, the deposit has presumably derived from a fluid moving in the uppermost levels of the El Tatio field; perhaps a heavily modified version of the brines found in the deep wells.



2016 ◽  
Vol 847 ◽  
pp. 485-489
Author(s):  
Xing Cai Zhang ◽  
Xiao Wei Cheng ◽  
Xiao Yang Guo

With the exploration of oil and gas in depth, shallow wells already can’t satisfy the requirement, therefore to explore and develop deep reservoirs is necessary. In the case of deep wells the loop temperature of bottom can reach to 150°C-200°C, which put forward a higher requirement for the high temperature resistance property of cement slurry. At present, many problems existed in the most of high temperature cement slurry. For example, high temperature resistance is not well, cement thickening time can’t adjust easily, mega-thermal sedimentation stability is unsatisfactory, and ultra-retarding phenomenon appeared for the top prone. After research indoors, we developed the ultra-high temperature slurry system by means of the investigation on cementing additives and select proper materials from high temperature resistant fluid loss additives, retarders, flowable agent at the same time. This system needs a lots of properties, such as, adjustable slurry thickening time below 200°C, great slurry sedimentation stability, API loss can be controlled at the range of 0-50ml, insensitive to temperature and density, could be used in low-density and conventional density cement etc. This system be used successfully in the well that loop temperature of bottom reaches to 185°C and get a good effect finally.



2020 ◽  
Vol 993 ◽  
pp. 1341-1350
Author(s):  
Xiu Jian Xia ◽  
Yong Jin Yu ◽  
Jian Zhou Jin ◽  
Shuo Qiong Liu ◽  
Ming Xu ◽  
...  

The conventional oil-well cement dispersant has the characteristics of poor dispersion at high temperature, poor compatibility with other additives, and environmental pollution during the production process. In this article, with ultra-early strong polyether monomer, acrylic acid, 2-acrylamine-2-methylpropyl sulfonic acid, sodium methacrylate as copolymer monomers, an environmentally friendly polycarboxylic acid dispersant, DRPC-1L, was prepared by the aqueous solution free-radical polymerization. The chemical composition and thermal stability of the synthetic copolymer were characterized by FTIR and TGA techniques. The evaluation results show that DRPC-1L has a wide temperature range (30~210 °C), good salt-resistance and dispersing effect. It can significantly improve the rheological performance of cement slurry, and it is well matched with oil-well cement additives such as fluid loss agent, retarder and so on. Moreover, it is beneficial to the mechanical strength development of set cement, especially the early compressive strength. It can also inhibit the abnormal gelation phenomenon of cement slurry, flash set, that occurs during high temperature thickening experiments, which plays an important role in enhancing the comprehensive performance of cement slurry. Consequently, the novel polycarboxylic acid dispersant has good application prospects in deep and ultra-deep wells cementing.



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