Experimental Study on the Wall Factor for Rod-Shaped Proppant Settling in Vertical Fracture

Author(s):  
Zhaopeng Zhu ◽  
Xianzhi Song ◽  
Xuezhe Yao ◽  
Shuo Zhu ◽  
Silin Jing

Abstract Hydraulic fracturing is an important technology to improve oil and gas production. In recent years, rod-shaped proppant has received increasing attention for its advantages in avoiding fracture closure and enhancing conductivity. Due to its special shape, the settling process in the fracture is more complicated than that of a spherical proppant. Accurate description of the wall factor of fracture on the settling rod-shaped proppant is pivotal in predicting the transport distance of rod-shaped proppant and improving the effect of fracturing. However, few researches have been reported about the fracture wall factor on the settling rod-shaped proppant. In this study, the transparent fracture model with different width and a high-speed camera were used to record the settling process of the rod-shaped proppant in the fracture. A total of 215 tests were carried out to analyze the effects of fluid properties, the equivalent dimensionless diameter, sphericity, and Reynolds number on the wall factor, involving the ranges of the equivalent dimensionless diameter and the particle Reynolds number are 0.03 to 1.47 and 0.03–1354.14, respectively. The settling processes of rod-shaped proppant under horizontal and vertical states were studied, and two wall factor models for the two states were established, respectively. The results show that the wall factor is a function of both the equivalent dimensionless diameter and Reynolds number. Finally, the prediction models of wall factor with the prediction error of 1.70 and 4.44% are established for these two Reynolds number regions, respectively. The results of this study can further improve the performance of rod-shaped proppant in hydraulic fracturing.

2014 ◽  
Vol 67 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Carlos Mouallem ◽  
Wilson Trigueiro de Sousa ◽  
Ivo Eyer Cabral ◽  
Adilson Curi

Hydraulic fracturing emerges currently, all over the world, as one of the more strategic techniques used by companies in the oil exploitation sector. This technique is characterized by its high productivity and profit in relation to conventional methods of hydrocarbon exploitation. However, in many countries, as is the case of Brazil, there are several divergences considering the employment of this methodology. Many renowned researchers attest that there are several irreversible environmental impacts generated by the use of this methodology. Among the main environmental impacts are the risk of groundwater level contamination, the risk of surface subsidence, and the risk of the environment contamination with fluids used in the process of the oil and gas extraction.


2021 ◽  
Author(s):  
David Russell ◽  
Price Stark ◽  
Sean Owens ◽  
Awais Navaiz ◽  
Russell Lockman

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.


Author(s):  
Steve Ingistov

This Paper describes the on-going efforts of finding the root-cause for the failures of high-energy (over 30,000 HP), high-pitch velocity (over 30,000 FPM) gear elements. These gear elements are presently operating in Oil and Gas Production Facilities. They are installed between the GT drivers and turbo-compressors. Turbo-compressors deliver high-pressure gas into the underground oil fields to enhance the oil production. The oldest Gas Compression Units were commissioned in 1995 and the latest in 1998. Since installation in 1995 at least 6 gear boxes experienced failures of the pinion (high speed gear) teeth. The Mean Time Between Failures (MTBF) of the pinion teeth was estimated around 34,000 operating hours. The costly shutdown of Gas Compression Units forced the management to seek advice within the company. The intent of this Paper is to share some field experiences and to present some corrective actions. The intent of this Paper is also to help Original Equipment Manufacturers (OEMs) in this case gear elements Manufacturers to develop better balance between cost, life and reliability. Sometimes the balance between these three parameters is difficult to maintain. Too often the gear elements Manufacturers are forced to compete on the price basis and as result the quality of the gear elements are sometimes compromised. In addition, several well-known gear elements Manufacturers stopped offering high energy, high-pitch velocity gear elements because they suffered serious failures of the gear elements on the test stand and also in the field.


Author(s):  
S. Ingistov

This Paper describes continuation of efforts to improve the low reliability of the high power, high pitch velocity gear boxes. These gear boxes are located in oil and gas production facilities (OAGPF) and serve to transmit the power from gas turbine drivers to large, two or three case turbo compressor trains. Life expectancy of these gear boxes did not meet predicted life expectancy of typical high speed, high energy gear boxes. This paper deals with various modifications of these gear boxes which were necessary to improve very low, initial 34% reliability. The series of modifications improved gear boxes life expectancies, however they never reached desired goal that is at least 10 years of continuous service without gear elements failures.


2020 ◽  
Vol 6 (8) ◽  
pp. eaav2110
Author(s):  
Daniel Raimi

Kondash et al. provide a valuable contribution to our understanding of water consumption and wastewater production from oil and gas production using hydraulic fracturing. Unfortunately, their claim that the water intensity of energy production using hydraulic fracturing has increased in all regions is incorrect. More comprehensive data show that, while the water intensity of production may have increased in regions such as the Permian basin, it has decreased by 74% in the Marcellus and by 19% in the Eagle Ford region. This error likely stems from an improper method for estimating energy production from wells: The authors use the median well to represent regional production, which systematically underestimates aggregate production volumes. Across all regions, aggregate data suggest that the water intensity of oil and natural gas production using hydraulic fracturing has increased by 19%. There also appears to be an error in estimates for water consumption in the Permian basin.


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