scholarly journals Reduction of Breakdown Pressure by Filter Cake Removal Using Thermochemical Fluids and Solvents: Experimental and Numerical Studies

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4407
Author(s):  
Zeeshan Tariq ◽  
Murtada Saleh Aljawad ◽  
Mohamed Mahmoud ◽  
Olalekan Alade ◽  
Muhammad Shahzad Kamal ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Chelating Agents ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Thermochemical Treatment ◽  
Chelating Agent ◽  
Scratch Test ◽  
Breakdown Pressure ◽  
Cake Formation ◽  
The Face

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.

Well Clean-Up Using a Combined Thermochemical/Chelating Agent Fluids

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Mohamed Mahmoud
Keyword(s):  
High Temperature ◽  
Filter Cake ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Chelating Agent ◽  
Drilling Fluids ◽  
Gas Wells ◽  
Oil And Gas Wells ◽  
Different Types ◽  
Cake Removal

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.

scholarly journals Application of Microemulsion Systems in the Formulation of Biodegradable Pre-Flush Fluid for Primary Cementing

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4683
Author(s):  
Elayne A. Araújo ◽  
Thaine T. Caminha ◽  
Evanice M. Paiva ◽  
Raphael R. Silva ◽  
Júlio Cézar O. Freitas ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Xrd Analysis ◽  
Oil Well ◽  
Cement Slurry ◽  
Removal Time ◽  
Primary Cementing ◽  
Flush Fluid ◽  
Cake Removal

Oil well cleanup fluids (pre-flushes) are intermediate fluids pumped ahead of the cement slurry; they are able to clean the well walls by removing the filter cake formed by the drilling fluid, and leave the surface water-wet. This work’s main objective was to use biodegradable microemulsion systems as cleanup fluids in order to reduce the environmental impact. Three microemulsion systems were formulated, each composed of an oil phase, a surfactant and three different aqueous phases: glycerol, glycerol:water (mass ratio 1:1), and fresh water. The results show that all microemulsion systems were effective with 100% filter cake removal, with a removal time of less than 60 s. The wettability test and fluid compatibility analyses exhibited advantageous performances, without phase separation, variations in viscosity, gelation, or flocculation. The compressive strength and X-ray diffractometry (XRD) analysis showed the influence of the glycerol on the cement slurry properties, with the compressive strength resistance ranging from 8.0 to 10.7 MPa, and resulted in the formation of portlandite.

The effect of filter cake deposition on the hydraulic conductivity of boreholes

2021 ◽  
Author(s):  
Rein Nijhof ◽  
Jan van Lopik ◽  
Martin Bloemendal
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Short Circuit ◽  
Small Diameter ◽  
Unconsolidated Sediments ◽  
Direct Result ◽  
Sealing Capacity ◽  
Cake Formation

<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>

Validation of a CFD Non-Newtonian Eulerian-Eulerian Model for Predicting Wellbore Filter Cake Formation

2016 ◽  
Vol 819 ◽  
pp. 376-381
Author(s):  
Ali I. Shehata ◽  
Mohamed Shokry ◽  
Khalid M. Saqr ◽  
Mohamed Shehadeh
Keyword(s):  
Filter Cake ◽  
Drilling Fluid ◽  
Drilling Process ◽  
Eulerian Model ◽  
Two Phase ◽  
Cake Formation ◽  
Fluid Particles ◽  
Drilling Conditions ◽  
Phase Fluid ◽  
Drilling Bit

During oil wellbore drilling processes, filter cake is formed on the sidewalls of the well hole due to filtration of drilling fluid particles. The filter cake is crucial to the drilling process, since it helps to maintain the wellbore hole, protects the drilling bit from jamming and facilitates the subsequent phases of the well development. The most important parameter for filter cake formation is its thickness and its variation due to drilling conditions. In this paper, the drilling fluid particles filtration process was simulated at conditions mimicking deep wellbore drilling. The drilling fluid was simulated as a non-Newtonian two-phase fluid of liquid and particles, utilizing an Eulerian-Eulerian approach. The model successfully predicted a filter cake thickness which agrees well with measurements and previous CFD work.

scholarly journals Study on the Behavior and Removal of Cadmium and Zinc Using Taraxacum officinale and Gazania under the Application of Biodegradable Chelating Agents

2021 ◽  
Vol 11 (4) ◽  
pp. 1557
Author(s):  
Naoki Kano ◽  
Takumi Hori ◽  
Haixin Zhang ◽  
Naoto Miyamoto ◽  
David Eva Vanessa Anak ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Chelating Agents ◽  
Environmental Control ◽  
Chelating Agent ◽  
Taraxacum Officinale ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Experimental Treatments ◽  
The One

The removal of cadmium (Cd) and zinc (Zn) from soil by phytoremediation was investigated using Taraxacum officinale and Gazania. A plant environmental control system was used to cultivate the plants. The effects of different biodegradable chelating agents (i.e., EDDS, HIDS, and GLDA), relative humidity, and other competitive metals on the adsorption of Cd and Zn were also studied. In addition, the approach for metal recovery was explored by extraction of metals from plants after phytoremediation using Gazania. The concentrations of Cd and Zn were determined by inductively coupled plasma mass spectrometry (ICP-MS). In addition, one-way analysis of variance (ANOVA) tests were performed.to determine significant differences between the experimental treatments adopted in this work. Consequently, the following main conclusions were obtained: (1) In the case of Taraxacum officinale, Cd and Zn could be removed even under the presence of other heavy metals. (2) By adding a chelating agent, the amount absorbed by the shoot generally increased. (3) In the case of Gazania, the concentration of Cd was higher in root than that in shoot, whereas the concentration of Zn was higher in the shoot than that in the root. (4) Taraxacum officinale was more suitable for phytoremediation of Cd than Gazania. (5) Cd and Zn could be extracted from plants by adding a low concentration of nitric acid. (6) The one-way ANOVA tests showed no statistically significant differences among the experimental treatments.

Granular-bed filtration assisted by filter-cake formation

2005 ◽  
Vol 155 (1) ◽  
pp. 5-16 ◽  
Author(s):  
K.-C. Lee ◽  
R. Pfeffer ◽  
A.M. Squires
Keyword(s):  
Filter Cake ◽  
Granular Bed ◽  
Cake Formation

Low ECD High Performance Invert Emulsion Drilling Fluids: Lab Development and Field Deployment

2021 ◽  
Author(s):  
Vikrant Wagle ◽  
Abdullah Yami ◽  
Michael Onoriode ◽  
Jacques Butcher ◽  
Nivika Gupta
Keyword(s):  
High Performance ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Field Performance ◽  
Superior Performance ◽  
Core Material ◽  
Drilling Fluids ◽  
Invert Emulsion ◽  
Field Deployment ◽  
Permeability Studies

Abstract The present paper describes the results of the formulation of an acid-soluble low ECD organoclay-free invert emulsion drilling fluid formulated with acid soluble manganese tetroxide and a specially designed bridging package. The paper also presents a short summary of field applications to date. The novel, non-damaging fluid has superior rheology resulting in lower ECD, excellent suspension properties for effective hole cleaning and barite-sag resistance while also reducing the risk of stuck pipe in high over balance applications. 95pcf high performance invert emulsion fluid (HPIEF) was formulated using an engineered bridging package comprising of acid-soluble bridging agents and an acid-soluble weighting agent viz. manganese tetroxide. The paper describes the filtration and rheological properties of the HPIEF after hot rolling at 300oF. Different tests such as contamination testing, sag-factor analysis, high temperature-high pressure rheology measurements and filter-cake breaking studies at 300oF were performed on the HPIEF. The 95pcf fluid was also subjected to particle plugging experiments to determine the invasion characteristics and the non-damaging nature of the fluids. The 95pcf HPIEF exhibited optimal filtration properties at high overbalance conditions. The low PV values and rheological profile support low ECDs while drilling. The static aging tests performed on the 95pcf HPIEF resulted in a sag factor of less than 0.53, qualifying the inherent stability for expected downhole conditions. The HPIEF demonstrated resilience to contamination testing with negligible change in properties. Filter-cake breaking experiments performed using a specially designed breaker fluid system gave high filter-cake breaking efficiency. Return permeability studies were performed with the HPIEF against synthetic core material, results of which confirmed the non-damaging design of the fluid. The paper thus demonstrates the superior performance of the HPIEF in achieving the desired lab and field performance.

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