scholarly journals Numerical Simulation of Natural Gas Hydrate Exploitation in Complex Structure Wells: Productivity Improvement Analysis

Mathematics ◽  
2021 ◽  
Vol 9 (18) ◽  
pp. 2184
Author(s):  
Hongyu Ye ◽  
Xuezhen Wu ◽  
Dayong Li
Keyword(s):  
Natural Gas ◽  
Numerical Models ◽  
Complex Structure ◽  
Horizontal Wells ◽  
Gas Production ◽  
Productivity Improvement ◽  
Drilling Technology ◽  
Single Well ◽  
Complex Structural ◽  
Advanced Drilling

About 90% of the world’s natural gas hydrates (NGH) exist in deep-sea formations, a new energy source with great potential for exploitation. There is distance from the threshold of commercial exploitation based on the single well currently used. The complex structure well is an efficient and advanced drilling technology. The improvement of NGH productivity through various complex structure wells is unclear, and there is no more complete combing. Thus, in order to evaluate their gas production characteristics, we establish a mathematical model for exploitation of NGH, and then 13 sets of numerical models based on the geological parameters of the Nankai Trough in Japan are developed and designed, including a single vertical well, a single horizontal well, 1~4 branch vertical wells, 1~4 branch horizontal wells, and 2~4 branch cluster horizontal wells. The research results indicate that wells with complex structures represented by directional wells and multilateral wells can significantly increase the area of water and gas discharge, especially cluster wells, whose productivity can be increased by up to 2.2 times compared with single wells. Complex structural wells will play an irreplaceable role in the future industrialization of NGH.

Simultaneous Hydraulic Fracturing Improves Completion Efficiency and Lowers Costs Per Foot

2021 ◽  
Author(s):  
David Russell ◽  
Price Stark ◽  
Sean Owens ◽  
Awais Navaiz ◽  
Russell Lockman
Keyword(s):  
Hydraulic Fracturing ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Asset Returns ◽  
Gas Production ◽  
Well Performance ◽  
Additional Time ◽  
Oil And Gas Production ◽  
Single Well ◽  
Lateral Length

Abstract Reducing well costs in unconventional development while maintaining or improving production continues to be important to the success of operators. Generally, the primary drivers for oil and gas production are treatment fluid volume, proppant mass, and the number of stages or intervals along the well. Increasing these variables typically results in increased costs, causing additional time and complexity to complete these larger designs. Simultaneously completing two wells using the same volumes, rates, and number of stages as for any previous single well, allows for more lateral length or volume completed per day. This paper presents the necessary developments and outcomes of a completion technique utilizing a single hydraulic fracturing spread to simultaneously stimulate two or more horizontal wells. The goal of this technique is to increase operational efficiency, lower completion cost, and reduce the time from permitting a well to production of that well—without negatively impacting the primary drivers of well performance. To date this technique has been successfully performed in both the Bakken and Permian basins in more than 200 wells, proving its success can translate to other unconventional fields and operations. Ultimately, over 200 wells were successfully completed simultaneously, resulting in a 45% increase in completion speed and significant decrease in completion costs, while still maintaining equivalent well performance. This type of simultaneous completion scenario continues to be implemented and improved upon to improve asset returns.

Research and Application of Segmented Acid Fracturing Technology in Horizontal Wells of Ultra Deep Carbonate Gas Reservoirs in Southwest China

2021 ◽  
Author(s):  
Yang Wang ◽  
Changlin Zhou ◽  
Huali Zhang ◽  
Tingting He ◽  
Xinyuan Tang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Southwest China ◽  
Horizontal Wells ◽  
Gas Production ◽  
Reservoir Temperature ◽  
Fracturing Fluid ◽  
Gas Reservoir ◽  
Acid Rock ◽  
Acid Fracturing ◽  
Temporary Plugging Agent

Abstract The Shuangyu gas reservoir in Southwest China is a fracture ultra deep carbonate gas reservoir. Its reservoir buried depth is more than 7000m, and the reservoir temperature is about 160°C. In the early stage, the vertical well acid fracturing method was used to obtain the natural gas production, but the gas production decreased rapidly after acid fracturing, which is difficult to achieve economic and efficient development. Segmented acid fracturing of horizontal wells is an effective way to greatly increase gas production. However, segmented acid fracturing of horizontal wells in Shuangyu ultra deep carbonate gas reservoir faces the following problems: (1)High reservoir temperature, fast acid rock reaction speed and short length of acid corrosion fracture. (2) The diameter of horizontal well is small (114.3mm), packer and other tools can not be put into the wellbore. In this paper, through laboratory tests, an acid fracturing fluid with temperature resistance of 160 °C and friction resistance of 35% of water is developed. The fracturing fluid has the characteristics of high viscosity and high concentration of hydrogen ions, which can not only fracture the formation, but also carry out effective acid etching on the fracture during the injection process. Through the experiment, the temporary plugging agent which can meet the temperature of 160 °C and the combination of temporary plugging agent can form a sealing layer in the fracture with the width of 4mm, and the maximum sealing pressure can reach 20MPa. The research results have been successfully applied in well y616. After fracturing, the daily output of natural gas in well Y616 is 1 million cubic meters, which is more than three times that of the surrounding vertical wells.

scholarly journals Horizontal well workover technology present situation and development trend

2021 ◽  
Vol 261 ◽  
pp. 01049
Author(s):  
Guohui Zhang ◽  
Peng Wang ◽  
Rong Chen ◽  
Baoping Duan ◽  
Guowen Zhang ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Complex Structure ◽  
Horizontal Wells ◽  
Development Trend ◽  
Low Permeability ◽  
Drilling Technology ◽  
Combined Action ◽  
Axial Compressive Stress ◽  
High Level ◽  
Low Permeability Reservoirs

In the downhole operation of horizontal Wells, the pipe string is subjected to the combined action of many kinds of loads. The pipe string may bend sinusoidal or spiral under the action of axial compressive stress, which will also increase the friction between the pipe string and the wellbore wall. Because of the existence of friction, to the milling, salvage, unstuck, sand and other construction to bring adverse effects. This paper describes the characteristics of horizontal well in fishing, sand washing, unlocking and casing milling. The paper introduces the development of horizontal well application, such as drilling technology matching for complex structure wells, high-level completion of lateral Wells, radial lateral wells in low permeability reservoirs and supporting technology for completion and production of horizontal wells.

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