Tubular String Characterization in High Temperature High Pressure Oil and Gas Wells

2018 ◽  
Author(s):  
Jiuping Xu ◽  
Zezhong Wu
SPE Journal ◽  
2018 ◽  
Vol 24 (05) ◽  
pp. 2033-2046 ◽  
Author(s):  
Hu Jia ◽  
Yao–Xi Hu ◽  
Shan–Jie Zhao ◽  
Jin–Zhou Zhao

Summary Many oil and gas resources in deep–sea environments worldwide are often located in high–temperature/high–pressure (HT/HP) and low–permeability reservoirs. The reservoir–pressure coefficient usually exceeds 1.6, with formation temperature greater than 180°C. Challenges are faced for well drilling and completion in these HT/HP reservoirs. A solid–free well–completion fluid with safety density greater than 1.8 g/cm3 and excellent thermal endurance is strongly needed in the industry. Because of high cost and/or corrosion and toxicity problems, the application of available solid–free well–completion fluids such as cesium formate brines, bromine brines, and zinc brines is limited in some cases. In this paper, novel potassium–based phosphate well–completion fluids were developed. Results show that the fluid can reach the maximum density of 1.815 g/cm3 at room temperature, which makes a breakthrough on the density limit of normal potassium–based phosphate brine. The corrosion rate of N80 steel after the interaction with the target phosphate brine at a high temperature of 180°C is approximately 0.1853 mm/a, and the regained–permeability recovery of the treated sand core can reach up to 86.51%. Scanning–electron–microscope (SEM) pictures also support the corrosion–evaluation results. The phosphate brine shows favorable compatibility with the formation water. The biological toxicity–determination result reveals that it is only slightly toxic and is environmentally acceptable. In addition, phosphate brine is highly effective in inhibiting the performance of clay minerals. The cost of phosphate brine is approximately 44 to 66% less than that of conventional cesium formate, bromine brine, and zinc brine. This study suggests that the phosphate brine can serve as an alternative high–density solid–free well–completion fluid during well drilling and completion in HT/HP reservoirs.


2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Mohamed Mahmoud

The well clean-up process involves the removal of impermeable filter cake from the formation face. This process is essential to allow the formation fluids to flow from the reservoir to the wellbore. Different types of drilling fluids such as oil- and water-based drilling fluids are used to drill oil and gas wells. These drilling fluids are weighted with different weighting materials such as bentonite, calcium carbonate, and barite. The filter cake that forms on the formation face consists mainly of the drilling fluid weighting materials (around 90%), and the rest is other additives such as polymers or oil in the case of oil-base drilling fluids. The process of filter cake removal is very complicated because it involves more than one stage due to the compatibility issues of the fluids used to remove the filter cake. Different formulations were used to remove different types of filter cake, but the problem with these methods is the removal efficiency or the compatibility. In this paper, a new method was developed to remove different types of filter cakes and to clean-up oil and gas wells after drilling operations. Thermochemical fluids that consist of two inert salts when mixed together will generate very high pressure and high temperature in addition to hot water and hot nitrogen. These fluids are sodium nitrate and ammonium chloride. The filter cake was formed using barite and calcite water- and oil-based drilling fluids at high pressure and high temperature. The removal process started by injecting 500 ml of the two salts and left for different time periods from 6 to 24 h. The results of this study showed that the newly developed method of thermochemical removed the filter cake after 6 h with a removal efficiency of 89 wt% for the barite filter cake in the water-based drilling fluid. The mechanisms of removal using the combined solution of thermochemical fluid and ethylenediamine tetra-acetic acid (EDTA) chelating agent were explained by the generation of a strong pressure pulse that disturbed the filter cake and the generation of the high temperature that enhanced the barite dissolution and polymer degradation. This solution for filter cake removal works for reservoir temperatures greater than 100 °C.


2013 ◽  
Vol 703 ◽  
pp. 143-146
Author(s):  
Ling Feng Li

Analysis on casing size and steel grade and application in high-temperature high-pressure gas wells are important in natural gas production engineering. This paper presents the standard casing size series, casing steel grade standard and code, types of casing steel grade, main problems in high-temperature high-pressure gas wells, using casing material suitable as solving means for high-temperature high-pressure gas well and application. For application, the study above is good and easy for on-the-spot application.


2021 ◽  
Vol 329 ◽  
pp. 01076
Author(s):  
Qilin Liu ◽  
Jian Yang ◽  
Lang Du ◽  
Jianxun Jiang ◽  
Dan Ni ◽  
...  

According to the formation and handling situation of hydrate in ultra-deep high-pressure sulfurcontaining gas wells in northwest Sichuan, the formation conditions of natural gas hydrate was studied based on previous studies on hydrate, the molecular dynamics of natural gas hydrate and the multiphase flow law of high-temperature high-pressure high-sulfur-containing gas wellbore were combined, and the pressure prediction model with high-temperature high-pressure sulfur-containing gas wells as the target was built. The chemical and physical control methods of wellbore hydrate plugging were discussed to provide the scientific theoretical basis for the prediction and control of hydrate in high-temperature high-pressure high-sulfurcontaining gas wells.


2021 ◽  
Author(s):  
Lei Wang ◽  
Jin Yang ◽  
Zhengkang Li ◽  
Xinyue He ◽  
Lei Li ◽  
...  

Abstract With the strengthening of exploration and development of deep strata and offshore oil and gas resources, more and more deep wells and deep-water wells have put forward higher requirements for drilling fluid performance. The high-temperature high-pressure of deep well and the low temperature environment of deep well have important influence on the rheology and density of drilling fluid. A new method for calculating the rheology and density of high -temperature high-pressure (HTHP) drilling fluid is proposed and studied in this paper. In this paper, the HTHP rheological data are used to predict the shear stress under different shear rates, and then the wellbore rheological parameters are predicted and analyzed. For the calculation of drilling fluid density, the classical component method static density calculation model established by Hoberock model based on drilling fluid components is analyzed and improved in this paper. The obtained model predicts that the maximum absolute error of drilling fluid density under different temperature and pressure is 0.02 g/cm3, and the absolute error is controlled within 2 %.


2011 ◽  
Vol 29 (2) ◽  
pp. 132-148 ◽  
Author(s):  
Z. Wu ◽  
J. Xu ◽  
X. Wang ◽  
K. Chen ◽  
X. Li ◽  
...  

2019 ◽  
Vol 12 (17) ◽  
Author(s):  
Nahid Shaikh ◽  
Karan Patel ◽  
Sivakumar Pandian ◽  
Manan Shah ◽  
Anirbid Sircar

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