scholarly journals One-Stage Calcium Carbonate Oil-Based Filter Cake Removal Using a New Biodegradable Acid System

2019 ◽  
Vol 11 (20) ◽  
pp. 5715 ◽  
Author(s):  
Salaheldin Elkatatny
Keyword(s):  
Calcium Carbonate ◽  
Removal Efficiency ◽  
Filter Cake ◽  
Acid System ◽  
Berea Sandstone ◽  
Core Samples ◽  
One Stage ◽  
Removal Experiments ◽  
Indiana Limestone ◽  
Cake Removal

Removal of the oil-based filter cake is a complex task especially in horizontal and multilateral wells. The presence of oil makes the removal process more challenging because the oil coats the weighting materials and prevents acid–filter cake interaction. Therefore, different additives are required to change the wettability of the filter cake to enhance the removal efficiency. This paper introduces a new biodegradable acid system (NBAS) that can efficiently remove oil-based filter cake in horizontal and multilateral wells where calcium carbonate is used as a weighting agent. The new biodegradable acid system (NBAS) consists of 50 vol.% biodegradable acid and 5 vol.% mutual solvent, and the remaining percent is deionized water. High-pressure high-temperature (HPHT) filtration experiments were performed to evaluate the filter cake removal efficiency and the retained permeability. The filtration and removal experiments were conducted using real core samples (Indiana limestone and Berea sandstone) at a temperature of 212 °F and 300 psi differential pressure. Afterward, the NBAS was evaluated by measuring physical properties and conducting corrosion, compatibility, and thermal stability studies. The obtained results showed that the NBAS was compatible and thermally stable for more than 48 h at 212 °F and 300 psi. The NBAS has a density of 1.05 g/cm3, viscosity of 1.47 cP, and surface tension of 32 dynes/cm at room temperature. The corrosion rate of the developed system was 0.03 lb/ft2, which is acceptable according to oil and gas industry best practices. Removal experiments showed that the filter cake was completely removed from the core samples. For Berea sandstone, 100% of the permeability was regained, while the retained permeability for Indiana limestone was 122.5%, confirming the complete removal of external and internal filter cake as well as core samples stimulation. The new acid system can be considered as an efficient solution for oil-based filter cake removal that is biodegradable and cost-effective, where the reservoir permeability can be regained in one-stage only.

A New Method of Evaluating the Filter-Cake Removal Efficiency

2002 ◽  
Author(s):  
C.R. Miranda ◽  
J.C. Leite ◽  
R.T. Lopes ◽  
L.F. Oliveira
Keyword(s):  
Removal Efficiency ◽  
Filter Cake ◽  
New Method ◽  
Cake Removal

scholarly journals Novel Cake Washer for Removing Oil-Based Calcium Carbonate Filter Cake in Horizontal Wells

2020 ◽  
Vol 12 (8) ◽  
pp. 3427
Author(s):  
Osama Siddig ◽  
Saad Al-Afnan ◽  
Salaheldin Elkatatny ◽  
Mohamed Bahgat
Keyword(s):  
Calcium Carbonate ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Butyl Ether ◽  
Drilling Technique ◽  
Impermeable Layer ◽  
Calcium Carbonate Dissolution ◽  
Emulsion Oil ◽  
Cake Removal

An impermeable layer “filter cake” usually forms during the overbalanced drilling technique. Even though it helps in protecting the formation from a further invasion of drilling fluids, the removal of this layer is essential for a proper cement job and to avoid any reduction in wellbore deliverability. The design of the removal process is complicated and depends on the filter cake composition and homogeneity. This paper presents an experimental evaluation on the usage of a novel cake washer (NCW) in the removal of a filter cake formed by an invert emulsion oil-based drilling fluid that contains calcium carbonate as a weighting material while drilling a horizontal reservoir. The proposed NCW is a mixture of organic acid, mutual solvent and nonionic surfactant. It is designed to enable restored wellbore permeability for a sustainable production. Since the filter cake mainly consists of the weighting material, the solubility of calcium carbonate in NCW at different ranges of temperature, duration and concentration was investigated. An actual casing joint was used to test the corrosion possibility of the treating solution. High-pressure and high-temperature (HPHT) filtration tests on ceramic discs and Berea sandstone core samples were conducted to measure the efficiency of the filter cake removal and the retained permeability. Ethylene glycol mono butyl ether (EGMBE) was used as a mutual solvent and the solubility was higher compared to when the mutual solvent was not used in the washer formulation. A significant increase in calcium carbonate dissolution with time was observed for a duration of 24 h. The solubility was found to be proportional to the concentration of NCW with optimum results of 99% removal at a temperature of around 212 °F. At those conditions, no major corrosion problems were detected. Permeability of the core retained its pristine value after the treatment.

scholarly journals Removal of Calcium Carbonate Water-Based Filter Cake Using a Green Biodegradable Acid

2020 ◽  
Vol 12 (3) ◽  
pp. 994 ◽  
Author(s):  
Abdelmjeed Mohamed ◽  
Salaheldin Elkatatny ◽  
Abdulaziz Al-Majed
Keyword(s):  
Calcium Carbonate ◽  
Corrosion Rate ◽  
Removal Efficiency ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Ceramic Filter ◽  
Carbonate Water ◽  
Filter Disc ◽  
Water Based ◽  
Acid Formulation

The filter cake is a very thin layer of solid particles deposited from the drilling fluid onto the surface of the drilled formation. This is essential during the drilling process as it reduces fluid filtrate invasion, contributing for the well’s integrity. When the drilling processes are over, this formation must be removed efficiently to allow for the primary cement jobs to be conducted efficiently, and for hydrocarbons to be produced without any restrictions. The removal process of the filter cake is challenging and requires specific techniques, depending on several factors including the filter cake homogeneity, drilling fluid components, weight of materials used, and the continuous phase of the drilling fluid (i.e., water or oil). This study evaluates the use of green biodegradable removal acid (GBRA) to dissolve calcium carbonate water-based filter cake. The removal efficiency of this new acid was analyzed using filtration and removal tests, conducted on a ceramic filter disc and real core samples at 212 °F. Then, the new formulation was subjected to physical properties measurements and biodegradation and corrosion tests. Furthermore, the performance of the new acid formulation was compared with 10 wt.% hydrochloric acid (HCl) to ensure its efficiency. The obtained results showed that the new acid formulation was effective at removing the filter cake, with a removal efficiency greater than 90%. The retained permeability was 100% and 94% with the ceramic filter disc and the real limestone core sample, respectively, confirming the good removal performance of the new acid formulation. The corrosion rate of GBRA (50 wt.%) at 212 °F was 0.032 lb/ft2, which was within the acceptable range according to oil industry practices (i.e., less than 0.05 lb/ft2 if the temperature is less than 250 °F), while HCl (10 wt.%) yielded a high corrosion rate of 0.68 lb/ft2.

scholarly journals Pellet Softening Process for the Removal of the Groundwater Hardness; Modelling and Experimentation

2019 ◽  
Vol 12 (3) ◽  
pp. 135-143 ◽  
Author(s):  
Fatin Abdul_kareem Ashoor ◽  
Amer D. Zmat ◽  
Muthanna H. AlDahhan
Keyword(s):  
Calcium Carbonate ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Solution Flow Rate ◽  
Pellet Size ◽  
Solution Flow ◽  
Bed Height ◽  
Naoh Solution ◽  
Softening Process ◽  
Calcium And Magnesium Ions

A lab scale pellet reactor (PR) was designed and fabricated to carry out extensive investigations on the removal efficiency of the hardness of groundwater.  The groundwater of 2200 – 2600 mg/L hardness was collected from Abdulla Ibnalhassan wells area located at the west desert of Al-Shinafiyah district (70 km to the southwest of Al-Dewaniyah city, Iraq). Both hydrodynamic parameters of the pellet reactor (porosity and fluidized bed height) and the parameters of calcium carbonate crystallization process (calcium carbonate equilibrium, pellet size, and density) were modeled and compared with the experimental results of the lab scale pellet reactor. The comparison showed that fair agreement between modeled and measured results was observed. The removal efficiency of both calcium and magnesium ions were 62.5-99% and 83-99% respectively. The removal efficiency was found to be strongly dependent on pH and the ratio of NaOH solution flow rate to the groundwater flow rate in the pellet reactor.

Filter Cake Cleanup Using HCl/Glycolic Acid System

2013 ◽  
Author(s):  
S. M. Elkatatny ◽  
A. M. Al Moajil ◽  
H. A. Nasr-El-Din
Keyword(s):  
Glycolic Acid ◽  
Filter Cake ◽  
Acid System
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