An Experimental Investigation of Drilling-Fluid Filter-Cake Removal by Acid Jetting

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.

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A New Technique to Characterize Drilling Fluid Filter Cake

10.2118/144098-ms ◽

2011 ◽

Cited By ~ 4

Author(s):

Salaheldin Elkatatny ◽

Mohamed Ahmednasreldin Mahmoud ◽

Hisham A. Nasr-El-Din

Keyword(s):

Filter Cake ◽

Drilling Fluid ◽

New Technique ◽

Fluid Filter ◽

A New Technique

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Failure modes of drilling fluid filter cake

Géotechnique ◽

10.1680/geot.2001.51.9.777 ◽

2001 ◽

Vol 51 (9) ◽

pp. 777-785 ◽

Cited By ~ 4

Author(s):

P. Cerasi ◽

K. Soga

Keyword(s):

Filter Cake ◽

Failure Modes ◽

Drilling Fluid ◽

Fluid Filter

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

Energies ◽

10.3390/en13184683 ◽

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.

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A simple NMR methodology for evaluating filter cake properties and drilling fluid-induced formation damage

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-019-00786-3 ◽

2019 ◽

Vol 10 (4) ◽

pp. 1643-1655 ◽

Cited By ~ 6

Author(s):

Abdulrauf R. Adebayo ◽

Badr S. Bageri

Keyword(s):

Filter Cake ◽

Rock Sample ◽

Drilling Fluid ◽

Material Balance ◽

Cumulative Distribution ◽

Fluid Loss ◽

Secondary Damage ◽

Volume Porosity ◽

Filtration Loss ◽

Cake Removal

Abstract An efficient drilling fluid will form a filter cake that will minimize the drilling fluid invasion into any drilled formation. Drilling fluid must therefore be adequately evaluated in the laboratory prior to field trial. Filter cake properties such as thickness, porosity, permeability, and pore structure are frequently evaluated using several techniques such as CT scan, SEM, and XRF. However, each of these techniques can evaluate only one or two filter cake properties. This paper presents a simple but novel NMR technique to evaluate filter cake properties such as thickness, pore volume, porosity, and possibly permeability. Furthermore, the amount and particle size distribution of solids that invaded a given rock sample can be obtained using the same technique. The full procedure was tested and verified using four identical rock samples. Drilling fluid invasion and filter cake deposition experiments were conducted on each of the samples, using the same drilling fluid but four different concentrations of fluid loss additive. NMR T2 relaxation measurements were taken at three different stages of each rock sample: before filter cake deposition; after fluid invasion and filter cake deposition; and after filter cake removal. A material balance analysis of the probability density function and cumulative distribution function of the measured T2 profile at the different stages of each sample yielded multiple filtration loss properties of the filter cake. The results obtained showed high accuracy of the NMR versus the current techniques. Moreover, this current method evaluated the majority of the filter cake properties at the same time and in situ hence eliminated the need of using multi-procedures that disturb the sample state. Finally, the presented method can also be used to evaluate secondary damage associated with filter cake removal process.

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