scholarly journals INFLUENCE OF CNT-NANOPARTICLES IN THE FILTRATE CHARACTERISTICS AND FILTER CAKE FORMATION OF A WATER-BASED DRILLING FLUID

Author(s):  
Anoop Kanjirakat ◽  
Arnel Carvero ◽  
Reza Sadr ◽  
Mahmood Amani
2021 ◽  
Author(s):  
Rein Nijhof ◽  
Jan van Lopik ◽  
Martin Bloemendal

<p>Efficient construction and operation of borehole heat exchangers (BHEs) are essential in its contribution to the energy transition. In practice, implementation of BHE at larger scale requires low construction costs and high production rates. This requires small diameter drillings to reduce drilling and backfilling material costs, in which achieving a proper backfilling is a challenge. At present, there is an urgent need to improve the available techniques with more effectively and efficiently backfill methods for BHEs. In current Dutch practice, sealing (to prevent short-circuit flow between penetrated aquifers) is achieved by using either clay or grouts as backfilling materials, both have their pro’s and con’s. In optimisation of applying backfilling materials and methods, the filter cake, formed during the drilling procedure, also has a sealing capacity and is overlooked in addressing the sealing of the borehole.</p><p> </p><p>In this study the effect of filter cake formation on sealing capacity in unconsolidated sediments is quantified. Filter cake formation in unconsolidated porous formations (aquifers) is a complex process, which is affected by pressure differences between the borehole and the aquifer, aquifer characteristics (e.g. grain size distribution, porosity and permeability) and drilling mud/fluid properties.</p><p>A laboratory configuration is designed to stimulate different scenarios during the construction of a BHE. Consequently, the effectiveness, in terms of hydraulic conductivity, of the formed filter cake is determined by falling head tests.</p><p>Uniform aquifers with the smallest grain size tested (D50 = 0.22 mm) show a two order of magnitude reduction in hydraulic conductivity, as a direct result of filter cake formation. In contrast, filter cake formation is absent in uniform more coarse sands (D50 ≥ 0.65 mm). This demonstrates that filter cake deposition is highly variable with the grain size of the aquifer penetrated. Moreover, the experiments performed indicate that the deposition of a filter cake is not limited by additive concentrations in the drilling fluid or the duration of drilling fluid exposure to the formation.</p><p>This preliminary study creates the foundation for further research, since the experiments demonstrate the potential of filter cakes to significantly contribute to the sealing capacity within a borehole.</p>


2014 ◽  
Vol 262 ◽  
pp. 51-61 ◽  
Author(s):  
Rugang Yao ◽  
Guancheng Jiang ◽  
Wei Li ◽  
Tianqing Deng ◽  
Hongxia Zhang

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4407
Author(s):  
Zeeshan Tariq ◽  
Murtada Saleh Aljawad ◽  
Mohamed Mahmoud ◽  
Olalekan Alade ◽  
Muhammad Shahzad Kamal ◽  
...  

The process of well cleanup involves the removal of an impermeable layer of filter cake from the face of the formation. The inefficient removal of the filter cake imposes difficulty on fracturing operations. Filter cake’s impermeable features increase the required pressure to fracture the formation. In this study, a novel method is introduced to reduce the required breakdown pressure to fracture the formation containing the water-based drilling fluid filter cake. The breakdown pressure was tested for five samples of similar properties using different solutions. A simulated borehole was drilled in the core samples. An impermeable filter cake using barite-weighted drilling fluid was built on the face of the drilled hole of each sample. The breakdown pressure for the virgin sample without damage (filter cake) was 6.9 MPa. The breakdown pressure increased to 26.7 MPa after the formation of an impermeable filter cake. Partial removal of filter cake by chelating agent reduced the breakdown pressure to 17.9 MPa. Complete dissolution of the filter cake with chelating agents resulted in the breakdown pressure approximately equivalent to the virgin rock breakdown pressure, i.e., 6.8 MPa. The combined thermochemical and chelating agent solution removed the filter cake and reduced the breakdown pressure to 3.8 MPa. Post-treatment analysis was carried out using nuclear magnetic resonance (NMR) and scratch test. NMR showed the pore size redistributions with good communication between different pores after the thermochemical removal of filter cake. At the same time, there was no communication between the different pores due to permeability impairment after filter cake formation. The diffusion coupling through NMR scans confirmed the higher interconnectivity between different pores systems after the combined thermochemical and chelating agent treatment. Compressive strength was measured from the scratch test, confirming that filter cake formation caused added strength to the rock that impacts the rock breakdown pressure. The average compressive strength of the original specimen was 44.5 MPa that increased to 73.5 MPa after the formation of filter cake. When the filter cake was partially removed, the strength was reduced to 61.7 MPa. Complete removal with chelating agents removed the extra strength that was added due to the filter cake presence. Thermochemical and chelating agents resulted in a significantly lower compressive strength of 25.3 MPa. A numerical model was created to observe the reduction in breakdown pressure due to the thermochemical treatment of the filter cake. The result presented in this study showed the engineering applications of thermochemical treatment for filter cake removal.


2021 ◽  
Vol 5 (2) ◽  
pp. 1-14
Author(s):  
Mahmoud O

The increasing demand for deeper drilling and more complicated wells fastens the way for improved drilling fluid (mud) technologies and promising additives. Several studies have shown numerous improvements in mud characteristics upon using ilmenite compared to the commonly used weighting materials. This study aims at investigating the removal of filter cake deposited by ilmenite water-based drilling fluid under harsh conditions using low-concentration (7.5 wt%) of hydrochloric acid (HCl) and chelating agent (HEDTA) to prevent iron precipitation during reaction. API filter press was used to conduct the filtration tests and generate the filter cake at a pressure ~ 300 psi and temperature ~ 250°F. Different sandstone cores of 2.5-in. diameter and 1-in. thickness were used to simulate the formation during filtration. Filtrate fluids were collected for 30 minutes as per API procedures and computerized tomography (CT) scan was used to characterize the cores with the deposited filter cakes. The filter cakes were soaked with HCl–chelate solution for six hours. Cores with the remaining filter cakes were CT scanned again. Effluent solutions resulting from the aforementioned soaking process were analyzed using inductively coupled plasma (ICP). Scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS) was used to analyze the dried filter cakes and remaining residue. CT scan and SEM-EDS showed two layers of the filter cake with different densities but similar elemental composition. Using 7.5 wt% of HCl can partially remove the filter cake generated by ilmenite water-based drilling fluids. Adding the chelate showed minimal impact on the filter cake removal-efficiency; however, it helped nullify the corrosion issues during the treatment. This study provides a step forward on the way to chemically remove ilmenite-based filter cake using low acid concentration and virtually overcome corrosion issues encountered while acidizing.


2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Jimoh K. Adewole ◽  
Musa O. Najimu

This study investigates the effect of using date seed-based additive on the performance of water-based drilling fluids (WBDFs). Specifically, the effects of date pit (DP) fat content, particle size, and DP loading on the drilling fluids density, rheological properties, filtration properties, and thermal stability were investigated. The results showed that dispersion of particles less than 75 μm DP into the WBDFs enhanced the rheological as well as fluid loss control properties. Optimum fluid loss and filter cake thickness can be achieved by addition of 15–20 wt % DP loading to drilling fluid formulation.


Author(s):  
Petar Mijić ◽  
Nediljka Gaurina-Međimurec ◽  
Borivoje Pašić

About 75% of all formations drilled worldwide are shale formations and 90% of all wellbore instability problems occur in shale formations. This increases the overall cost of drilling. Therefore, drilling through shale formations, which have nanosized pores with nanodarcy permeability still need better solutions since the additives used in the conventional drilling fluids are too large to plug them. One of the solutions to drilling problems can be adjusting drilling fluid properties by adding nanoparticles. Drilling mud with nanoparticles can physically plug nanosized pores in shale formations and thus reduce the shale permeability, which results in reducing the pressure transmission and improving wellbore stability. Furthermore, the drilling fluid with nanoparticles, creates a very thin, low permeability filter cake resulting in the reduction of the filtrate penetration into the shale. This thin filter cake implies high potential for reducing the differential pressure sticking. In addition, borehole problems such as too high drag and torque can be reduced by adding nanoparticles to drilling fluids. This paper presents the results of laboratory examination of the influence of commercially available nanoparticles of SiO2 (dry SiO2 and water-based dispersion of 30 wt% of silica), and TiO2 (water-based dispersion of 40 wt% of titania) in concentrations of 0.5 wt% and 1 wt% on the properties of water-based fluids. Special emphasis is put on the determination of lubricating properties of the water-based drilling fluids. Nanoparticles added to the base mud without any lubricant do not improve its lubricity performance, regardless of their concentrations and type. However, by adding 0.5 wt% SiO2-disp to the base mud with lubricant, its lubricity coefficient is reduced by 4.6%, and by adding 1 wt% TiO2-disp to the base mud with lubricant, its lubricity coefficient is reduced by 14.3%.


2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Salaheldin Elkatatny ◽  
Mohamed Mahmoud ◽  
Hisham A. Nasr-El-Din

Previous studies considered the water-based drilling fluid filter cake as homogenous, containing one layer with an average porosity and permeability. The filter cake was recently proved to be heterogeneous, containing two layers with different properties (thickness, porosity and permeability). Heterogeneity of the filter cake plays a key role in the design of chemical treatments needed to remove the filter cake. The objectives of this study are to describe filter cake buildup under static and dynamic conditions, determine change in the filter medium properties, and obtain the local filtration properties for each layer in the filter cake. A high pressure high temperature (HPHT) filter press was used to perform the filtration process at 225 °F and 300 psi. A CT (computed tomography) scanner was used to measure the thickness and porosity of the filter cake. The results obtained from the CT scan showed that under static conditions, the formation of filter cake changed from compression to buildup; while under dynamic conditions, the filter cake was formed under continuous buildup. The CT results explained the changes in the thickness and porosity of each layer of the filter cake with time. The CT scans showed the change in the properties of the ceramic disk, such as porosity and permeability, which affect the calculation of the filter cake permeability. The change of the properties of the filter medium was ignored in previous studies.


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