Successfull Drilling of Oil and Gas Wells by Optimisation of Drilling Fluid Solids Control- A Practical and Theoretical Evaluation.

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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Potential use of basidiomycota Trametes hirsuta MT-17.24 in biodegradation of polyanionic cellulose

Proceedings of universities Applied chemistry and biotechnology ◽

10.21285/2227-2925-2021-11-3-472-480 ◽

2021 ◽

Vol 11 (3) ◽

pp. 472-480

Author(s):

A. V. Zubchenko ◽

E. Yu. Kozhevnikova ◽

A. V. Barkov ◽

Yu. A. Topolyuk ◽

A. V. Shnyreva ◽

...

Keyword(s):

Enzyme Preparation ◽

Oil And Gas ◽

Drilling Fluid ◽

Schizophyllum Commune ◽

Cellulase Activity ◽

Drilling Fluids ◽

Gas Wells ◽

Trametes Hirsuta ◽

Enzyme Preparations ◽

Oil And Gas Wells

Abstract: Despite their efficiency, existing methods to dispose of drilling fluids used in the construction of oil and gas wells (chemical treatment of spent solutions, thermal method, thickening) are often expensive and unsustainable. Basidiomycota are natural xylotroph destructors that process lignocellulosic substrate – one of the most stable biopolymers in nature. Prospects for using enzyme preparations based on Basidiomycota as biodestructors of organic substances are evident due to the high efficiency and zero-waste production. The aim was to obtain an enzyme preparation based on the Trametes hirsute MT-17.24 Basidiomycota strain and evaluate its ability to biodegrade polyanionic cellulose, used as a viscosifier for drilling fluids in the construction and repair of oil and gas wells. Screening of cellulase activity of the following strains was carried out: Fomitopsis pinicola MT-5.21, Fomes fomentarius MT-4.05, Lactarius necator, Schizophyllum commune MT-33.01, Trametes versicolor It-1, Trametes hirsute MT-17.24, Trametes hirsuta MT-24.24. To obtain the enzyme preparation, the T. hirsuta MT-17.24 strain was selected, which demonstrated the highest coefficient of cellulase activity (10.9). A medium for solid-phase cultivation of this strain was selected. Enzymatic activity of the enzyme preparation was studied on a model drilling fluid. A 10-hour experiment showed that the use of a 1% enzyme preparation leads to a decrease in the plastic viscosity of the drilling fluid from 16 to 8 mPa·s. The research results demonstrate the efficiency of enzyme preparations based on Basidiomycota in the biodestruction of polyanionic cellulose.

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Experiments on Fluid Placement in a Confined Pipe: Fluid Mechanics Analysis for Plug and Abandonment Applications

Volume 11: Petroleum Technology ◽

10.1115/omae2020-18077 ◽

2020 ◽

Author(s):

Soheil Akbari ◽

Seyed Mohammad Taghavi

Keyword(s):

Oil And Gas ◽

Drilling Fluid ◽

Heavy Fluid ◽

Cement Slurry ◽

Gas Wells ◽

Inflow Velocity ◽

Operation Conditions ◽

Oil And Gas Wells ◽

Cement Plug

Abstract Plug and abandonment (P&A) of oil and gas wells is an essential process to prevent the oil and gas reservoir fluids migration over time and possibly contaminating other formations and also fresh water resources. In order to plug and abandon a well, a high quality cement plug placement is required. One of the most common methods of cement plug placement is the dump bailing method. In this method, a fixed volume of cement is dumped using a bailer on a mechanical plug in the wellbore. The cement slurry occupies the wellbore and also the annular region outside the dump bailer. In the processes of cement slurry placement, an extensive range of Newtonian or non-Newtonian fluids is used to remove the in-situ fluid (drilling fluid or water) in the wellbore. Based on the large number of parameters such as the density and viscosity differences between the fluids, the geometry type (pipe, annulus, etc.), the operation conditions (velocity, geometry inclination, dumping height), various kinds of placement and mixing flows can occur, and different flow regimes (e.g. inertial, viscous) can develop. In this paper, we experimentally study the placement of a heavy fluid to replace an in-situ light fluid in an inclined closed-end pipe (representative of the dump bailing method). The two fluids are Newtonian and miscible, and they have the same viscosity. We investigate the effects of some of the flow parameters such as the dumping height, the pipe inclination, and the inflow velocity of the heavy fluid on the degree of mixing and the placement quality and efficiency. Our results show that the the most efficient displacement happens with the shortest dumping height and at lower inclination from vertical. Also, a high inflow velocity displaces the light fluid promptly with more mixing in comparison with a low inflow rate. The results can help us to develop strategies for improving the dump bailing method in the P&A of the oil and gas wells.

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Specially Formulated Drilling Fluid Prevents Differential Sticking, Mud Losses, and Wellbore Instability in Oil and Gas Wells in Saudi Arabia

10.2118/124087-ms ◽

2009 ◽

Author(s):

Adel Abdulaziz Al-Ansari ◽

Mohammed Hasan Kilani

Keyword(s):

Saudi Arabia ◽

Oil And Gas ◽

Drilling Fluid ◽

Gas Wells ◽

Wellbore Instability ◽

Oil And Gas Wells

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Investigation of Non-Linear Rheological Characteristics of Barite-Free Drilling Fluids

Fluids ◽

10.3390/fluids6090327 ◽

2021 ◽

Vol 6 (9) ◽

pp. 327

Author(s):

Ekaterina Leusheva ◽

Nataliia Brovkina ◽

Valentin Morenov

Keyword(s):

Oil And Gas ◽

Drilling Fluid ◽

Rheological Parameters ◽

Drilling Fluids ◽

Drilling Mud ◽

Gas Wells ◽

Oil And Gas Wells ◽

Fluid Properties ◽

Hydrolyzed Polyacrylamide ◽

Drilling Muds

Drilling fluids play an important role in the construction of oil and gas wells. Furthermore, drilling of oil and gas wells at offshore fields is an even more complex task that requires application of specialized drilling muds, which are non-Newtonian and complex fluids. With regard to fluid properties, it is necessary to manage the equivalent circulation density because its high values can lead to fracture in the formation, loss of circulation and wellbore instability. Thus, rheology of the used drilling mud has a significant impact on the equivalent circulation density. The aim of the present research is to develop compositions of drilling muds with a low solids load based on salts of formate acid and improve their rheological parameters for wells with a narrow drilling fluid density range. Partially hydrolyzed polyacrylamide of different molecular weights was proposed as a replacement for hydrolized polyacrylamide. The experiment was conducted on a Fann rotary viscometer. The article presents experimentally obtained data of indicators such as plastic viscosity, yield point, nonlinearity index and consistency coefficient. Experimental data were analyzed by the method of approximation. Analysis is performed in order to determine the most suitable rheological model, which describes the investigated fluids’ flow with the least error.

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