scholarly journals Experimental Investigation of the Effects of Drilling Fluid Activity on the Hydration Behavior of Shale Reservoirs in Northwestern Hunan, China

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3151 ◽  
Author(s):  
Han Cao ◽  
Zheng Zhang ◽  
Ting Bao ◽  
Pinghe Sun ◽  
Tianyi Wang ◽  
...  

The interaction between drilling fluid and shale has a significant impact on wellbore stability during shale oil and gas drilling operations. This paper investigates the effects of the drilling fluid activity on the surface and osmotic hydration characteristics of shale. Experiments were conducted to measure the influence of drilling fluid activity on surface wettability by monitoring the evolution of fluid-shale contact angles. The relationship between drilling fluid activity and shale swelling ratio was determined to investigate the osmotic hydration behavior. The results indicate that, with increasing drilling fluid activity, the fluid–shale contact angles gradually increase—the higher the activity, the faster the adsorption rate; and the stronger the inhibition ability, the weaker the surface hydration action. The surface adsorption rate of the shale with a KCl drilling fluid was found to be the highest. Regarding the osmotic hydration action on the shale, the negative extreme swelling ratio (b) of the shale was found to be: bKCl < bCTAB < bSDBS. Moreover, based on the relationship between the shale swelling ratio and drilling fluid activity, shale hydration can be divided into complete dehydration, weak dehydration, surface hydration, and osmotic hydration, which contributes to the choice of drilling fluids to improve wellbore stability.

Author(s):  
Bunyami Shafie ◽  
Lee Huei Hong ◽  
Phene Neoh Pei Nee ◽  
Fatin Hana Naning ◽  
Tze Jin Wong ◽  
...  

Drilling mud is a dense, viscous fluid mixture used in oil and gas drilling operations to bring rock cuttings to the earth's surface from the boreholes as well as to lubricate and cool the drill bit. Water-based mud is commonly used due to its relatively inexpensive and easy to dispose of. However, several components and additives in the muds become increasingly cautious and restricted. Starch was introduced as a safe and biodegradable additive into the water-based drilling fluid, in line with an environmental health concern. In this study, the suitability of four local rice flours and their heat moistures derivatives to be incorporated in the formulation of water-based drilling fluid was investigated. They were selected due to their natural amylose contents (waxy, low, intermediate, and high). They were also heat moisture treated to increase their amylose contents. Results showed that the addition of the rice flours into water-based mud significantly reduced the density, viscosity, and filtrate volume. However, the gel strength of the mud was increased. The rice flours, either native or heat moisture treated, could serve as additives to provide a variety of low cost and environmentally friendly drilling fluids to be incorporated and fitted into different drilling activity.


2017 ◽  
Vol 899 ◽  
pp. 469-473 ◽  
Author(s):  
Irineu Petri Jr. ◽  
Jéssika Marina dos Santos ◽  
Arley Silva Rossi ◽  
Marina Seixas Pereira ◽  
Claudio Roberto Duarte ◽  
...  

Drill cuttings generated by oil and gas drilling process are incorporated into the drilling fluid to ensure an efficient drilling and solids removal. The drilling rigs have a separation system accountable for separating drill cuttings and drilling fluids. Microwave drying is a new technology of separation that has been studied as an alternative to the currently drill cuttings dryer used. The results obtained in preliminary studies showed that this microwave drying is sensitive to different oxides presents into the rock. Thus, this study aimed to describe the microwave heating kinetics of some rocks in order to verify the interaction of oxides with electromagnetic waves. For this, the oxide contents of the rocks were determined by X-ray Fluorescence and different rocks were heated in a microwave heating unit. The results showed that the relationship between the temperature and heating time is exponential and depends on the rock oxide contents. It was found that the iron oxides may be unstable at microwave and rocks with high levels of magnesium oxides and sulfates tend to be good absorbers of microwave. Rocks containing high levels of calcium, silicon, titanium, barium and chloride (NaCl) are not good absorbers of microwave. It was also noted that faster solid heating, lesser the efficiency of microwave drying.


2021 ◽  
Author(s):  
Sercan Gul

Abstract Drilling fluid (mud) serves various purposes in drilling operations, the most important being the primary well control barrier to prevent kicks and blowouts. Other duties include, but not limited to, maintaining wellbore stability, removing and transporting formation cuttings to the surface, cooling and lubricating downhole tools, and transmitting hydraulic energy to the drill bit. Mud quality is therefore related to most of the problems in drilling operations either directly or indirectly. The physics-based models used in the industry with drilling fluid information (i.e., cuttings transport, well hydraulics, event detection) are computationally expensive, difficult to integrate for real-time analysis, and not always applicable for all drilling conditions. For this reason, researchers have shown extensive interest in machine learning (ML) approaches to alleviate their fluid-related problems. In this study, a comprehensive review of the abundant literature on the various applications of ML in oil and gas operations, concentrating mainly on drilling fluids, is presented. It was shown that leveraging state-of-the-art supervised and unsupervised ML methods can help predict or eliminate most fluid-related issues in drilling. The review discusses various ML methods, their theory, applications, limitations, and achievements.


2021 ◽  
Author(s):  
Jiafeng Jin ◽  
Kaihe Lv ◽  
Jinsheng Sun ◽  
Yingrui Bai ◽  
Jingping Liu ◽  
...  

Abstract The ever-mounting drilling operations of the petroleum industry has been accompanied by tremendous wasted drilling fluid, Polycyclic Aromatic Hydrocarbons (PAHs) in which pose a huge threat to the health of human and ecosystem. Varying approaches have been proposed to remediate the damage caused by wasted drilling fluid, among which photocatalysis has been one of the most promising approaches for organic contaminants removal. The latest investigation shows that Bi2WO6 decorated on hydrophobic CNT can remove up to 80 % organic contaminant within a short time, exhibiting a preferable photocatalytic performance. Moreover, this hydrophobic CNT can play a vital role in stabilizing the wellbore due to its excellent water repellent. The objective of the study was to find out the effect of Bi2WO6 modified hydrophobic CNT on the PAHs photodegradation and wellbore stability in the process of drilling. Bi2WO6 as a near-infrared driven photocatalyst has attracted worldwide attention due to its preferable oxygen vacancy and quantum efficiency. However, the application of Bi2WO6 was impeded by the low migration efficiency of photo-generated carriers. The combination of Bi2WO6 and composite with good conductivity has been an effective method to resolve this problem. The instability of wellbore caused by shale hydration during oil and gas drilling operations also brings a huge challenge. In this study, a photocatalyst with wellbore stabilization capacity is achieved by hydrophobic CNT modified via Bi2WO6 sheet with nano-size. The fluid loss and wettability property were measured to evaluate the wellbore stabilization capacity of this novel agent. Meanwhile, photodegradation experiments and pathway analysis were conducted to evaluate the effect of photodegradation by Bi2WO6/CNT on the organic contaminants. Data of photodegradation indicated that the PAHs can be degraded up to 80% after treated by Bi2WO6/CNT, the migration efficiency of photogenerated carriers improved significantly. A slight decrease in fluid loss and distinctive increase in viscosity can be observed after treated with 0.3% Bi2WO6/CNT solution. The results of the rheology test verified that the photocatalyst has little effect on the rheological properties of drilling fluid. The result of SEM indicated that this novel Bi2WO6/CNT composite with a bombax structure can absorb preferentially organic contaminants, which is good at in-situ photodegradation and prevention of water invasion. To sum up, PAHs in wasted drilling fluids can be photodegraded by the novel Bi2WO6 nano-sheet modified CNT, and the stability of wellbore can also be significantly enhanced due to wettability alteration.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chuanliang Yan ◽  
Jingen Deng ◽  
Baohua Yu

Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale hydration is measured with the downhole temperature and pressure condition, then the penetration migrate law of drilling fluid filtrate around the wellbore is calculated. Furthermore, the changing rules of shale mechanical properties affected by hydration and water absorption are studied through experiments. The relationships between shale mechanical parameters and the water content are established. The wellbore stability model chemical-mechanical coupling is obtained based on the experimental results. Under the action of drilling fluid, hydration makes the shale formation softened and produced the swelling strain after drilling. This will lead to the collapse pressure increases after drilling. The study results provide a reference for studying hydration collapse period of shale.


2021 ◽  
Vol 881 ◽  
pp. 33-37
Author(s):  
Wei Na Di

The application of nanomaterials in oil and gas fields development has solved many problems and pushed forward the development of petroleum engineering technology. Nanomaterials have also been used in wellbore fluids. Nanomaterials with special properties can play an important role in improving the strength and flexibility of mud cake, reducing friction between the drill string and wellbore and maintaining wellbore stability. Adding nanomaterials into the cement slurry can eliminate gas channeling through excellent zonal isolation and improve the cementing strength of cement stone, thereby facilitating the protection and discovery of reservoirs and enhancing the oil and gas recovery. This paper tracks the application progress of nanomaterials in wellbore fluids in oil and gas fields in recent years, including drilling fluids, cement slurries. Through the tracking and analysis of this paper, it is concluded that the applications of nanomaterials in wellbore fluids in oil and gas fields show a huge potential and can improve the performance of wellbore fluids.


Author(s):  
E.A. Flik ◽  
◽  
Y.E. Kolodyazhnaya

The article assesses the environmental safety of drilling fluids that are currently widely used in the oil and gas industry. It shows active development of water-based drilling fluid systems using xanthan biopolymer.


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.


2020 ◽  
Vol 7 (2) ◽  
pp. 191230
Author(s):  
Yuhuan Bu ◽  
Rui Ma ◽  
Jiapei Du ◽  
Shenglai Guo ◽  
Huajie Liu ◽  
...  

This research work designed a novel mud-cake solidification method to improve the zonal isolation of oil and gas wells. The calculation methodology of mud-cake compressive strength was proposed. The optimal formula of activator and solid precursors, the proper activating time and the best activator concentration were determined by the compressive strength test. The effects of solid precursors on the properties of drilling fluid were evaluated. Test results show that the respective percentage of bentonite, metakaolin, slag and activator is 1 : 1 : 0.3 : 0.8, as well as the optimum ratio of Na 2 SiO 3 /NaOH is 40 : 1. The optimum concentration of activator is 0.21 and the activating time should be more than 10 min. The solid precursors did not show any bad influence on the rheological property of drilling fluids. Even though the compressive strength decreased when the solid precursors blended with barite, the strength values can still achieve 8 MPa. The reaction of metakaolin and activator formed cross-link structure in the mud-cake matrix, which enhanced the connection of the loose bentonite particles, lead to the significant enhancement of shear bonding strength and hydraulic bonding strength. This mud-cake solidification method provides a new approach to improve the quality of zonal isolation.


2020 ◽  
Author(s):  
Xian-Bin Huang ◽  
Jin-Sheng Sun ◽  
Yi Huang ◽  
Bang-Chuan Yan ◽  
Xiao-Dong Dong ◽  
...  

Abstract High-performance water-based drilling fluids (HPWBFs) are essential to wellbore stability in shale gas exploration and development. Laponite is a synthetic hectorite clay composed of disk-shaped nanoparticles. This paper analyzed the application potential of laponite in HPWBFs by evaluating its shale inhibition, plugging and lubrication performances. Shale inhibition performance was studied by linear swelling test and shale recovery test. Plugging performance was analyzed by nitrogen adsorption experiment and scanning electron microscope (SEM) observation. Extreme pressure lubricity test was used to evaluate the lubrication property. Experimental results show that laponite has good shale inhibition property, which is better than commonly used shale inhibitors, such as polyamine and KCl. Laponite can effectively plug shale pores. It considerably decreases the surface area and pore volume of shale, and SEM results show that it can reduce the porosity of shale and form a seamless nanofilm. Laponite is beneficial to increase lubricating property of drilling fluid by enhancing the drill pipes/wellbore interface smoothness and isolating the direct contact between wellbore and drill string. Besides, laponite can reduce the fluid loss volume. According to mechanism analysis, the good performance of laponite nanoparticles is mainly attributed to the disk-like nanostructure and the charged surfaces.


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