An Integrated Approach to Efficient Drilling through Unstable Coal Intervals Using Different Types of Mud in the Yamal Region

2021 ◽  
Author(s):  
Alexander Viktorovich Kabanov ◽  
Aydar Ramilevich Galimkhanov ◽  
Andrey Borisovich Kharitonov ◽  
Alexander Mikhailovich Matsera ◽  
Valery Viktorovich Pogurets ◽  
...  

Abstract This article is a description of an integrated engineering approach to solutions selection for efficient and safe drilling of unstable intervals represented by interbedded coal and argillite layers. Due to specific features of these formations, any significant mechanical stress, as well as penetration of drilling fluid filtrate, may lead to wellbore instability regardless of the drilling mud type used. The paper presents a description of the features of drilling in unstable intervals with various types of drilling muds (WBM/OBM) in Yamalo-Nenets Autonomous Okrug (YNAO). Experience has shown that drilling through coal intervals prone to instability may cause significant non-productive time (NPT). Such wells should be designed with an integrated engineering approach, which covers the entire cycle: starting with the well path planning, casing setting depths selection, BHA design and drilling regimes of the risk interval. No less important, detailed development of solutions for drilling muds. During the study the main causes of issues in wells drilled through the interbedded formations of coal and argillites in two fields were identified. As a result, a set of measures was developed to minimize risks for each type of mud (OBM and WBM): – Revision of the initial well design solutions. Selection of optimal mud weight based on the experience gained and the geomechanical model – Revision of chemicals concentrations together with the use of additional additives – Placement of stabilizing pills across unstable intervals – Well path optimization – Development of safe drilling procedures. The measures developed for various types of drilling muds allowed minimizing the NPT and successfully completing the wells on time. The experience gained formed the basis for recommendations to prevent issues associated with the coal layers instability in the region.

2021 ◽  
Author(s):  
Anna Vladimirovna Norkina ◽  
Sergey Mihailovich Karpukhin ◽  
Konstantin Urjevich Ruban ◽  
Yuriy Anatoljevich Petrakov ◽  
Alexey Evgenjevich Sobolev

Abstract The design features and the need to use a water-based solution make the task of ensuring trouble-free drilling of vertical wells non-trivial. This work is an example of an interdisciplinary approach to the analysis of the mechanisms of instability of the wellbore. Instability can be caused by a complex of reasons, in this case, standard geomechanical calculations are not enough to solve the problem. Engineering calculations and laboratory chemical studies are integrated into the process of geomechanical modeling. The recommendations developed in all three areas are interdependent and inseparable from each other. To achieve good results, it is necessary to comply with a set of measures at the same time. The key tasks of the project were: determination of drilling density, tripping the pipe conditions, parameters of the drilling fluid rheology, selection of a system for the best inhibition of clay swelling.


2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Osei H

High demand for oil and gas has led to exploration of more petroleum resources even at remote areas. The petroleum resources are found in deeper subsurface formations and drilling into such formations requires a well-designed drilling mud with suitable rheological properties in order to avoid or reduce associated drilling problems. This is because rheological properties of drilling muds have considerable effect on the drilling operation and cleaning of the wellbore. Mud engineers therefore use mud additives to influence the properties and functions of the drilling fluid to obtain the desired drilling mud properties especially rheological properties. This study investigated and compared the impact of barite and hematite as weighting agents for water-based drilling muds and their influence on the rheology. Water-based muds of different concentrations of weighting agents (5%, 10%, 15% and 20% of the total weight of the drilling mud) were prepared and their rheological properties determined at an ambient temperature of 24ᵒC to check their impact on drilling operation. The results found hematite to produce higher mud density, plastic viscosity, gel strength and yield point when compared to barite at the same weighting concentrations. The higher performance of the hematite-based muds might be attributed to it having higher specific gravity, better particle distribution and lower particle attrition rate and more importantly being free from contaminants. The water-based muds with hematite will therefore be more promising drilling muds with higher drilling and hole cleaning efficiency than those having barite.


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6246
Author(s):  
Borivoje Pašić ◽  
Nediljka Gaurina-Međimurec ◽  
Petar Mijić ◽  
Igor Medved

The drilling of clay-rich formations, such as shale, is an extremely demanding technical and technological process. Shale consists of mixed clay minerals in different ratios and in contact with water from drilling mud. It tends to swell and cause different wellbore instability problems. Usually, the petroleum industry uses various types of salt and/or polymers as shale hydration inhibitors. The aim of this research was to determine whether nanoparticles can be used as shale swelling inhibitors because due to their small size they can enter the shale nanopores, plug them and stop further penetration of mud filtrate into the shale formation. Swelling of bentonite-calcium carbonate pellets after 2 and 24 h in water and drilling mud (water, bentonite, PAC and NaOH) without nanoparticles and with addition of TiO2 (0.5, 1 and 1.5 wt%) and SiO2 (0.5, 1 and 1.5 wt%) nanoparticles was measured using a linear swell meter. Additionally, granulometric analyses of bentonite as well as the zeta potential of tested muds containing nanoparticles were performed. Based on the laboratory research, it can generally be concluded that the addition of SiO2 and TiO2 nanoparticles in water and base drilling mud reduces the swelling of pellets up to 40.06%.


1986 ◽  
Vol 86 ◽  
Author(s):  
George M. Deeley ◽  
Larry W. Canter ◽  
Joakim G. Laguros

Water based drilling muds typically contain clays, barite, lime, caustic soda and other chemicals, such as polymers. Land disposal of these wastes raises the possibility of groundwater pollution which can be abated if the waste is stabilized either by chemical reaction or by solidification through some form of cementation. Many ASTM high-calcium (Class C) fly ashes are cementitious and thus may be useful in stabilization of drilling mud. The basic idea is to stabilize the clay-containing muds using the model of soil and roadbed stabilization with high-calcium fly ash [1]. Fly ash that is not utilized is considered to be a solid waste, so this application would would actually constitute codisposal of two wastes.


1983 ◽  
Vol 23 (01) ◽  
pp. 11-20 ◽  
Author(s):  
Syed M. Hussaini ◽  
Jamal J. Azar

Abstract Experiments are conducted with actual drilling muds to study the behavior of drilled cuttings in a vertical annulus. The effect of parameters such as particle size, flow rate, apparent viscosity, and yield point to plastic viscosity ratio on mud-carrying capacity are studied. The applicability of a semiempirical transport model developed by Zeidler also is investigated. It has been shown that in vertical annuluses, the fluid annular velocity has a major effect on the carrying capacity of muds, while the other parameters have an effect only at low to medium fluid annular velocities. We also conclude that Zeidler's semiempirical formulations for the prediction of drilled cuttings behavior are valid with certain limitations. Introduction One of the most important functions of a drilling fluid is to transpose the drilled particles (cuttings) generated by the drill bit to the surface through the wellbore annulus. This commonly is called the "carrying capacity" of drilling mud. Factors affecting the ability of drilling muds to lift cuttings arefluid rheological properties and flow rate,particle settling velocities,particle size and size distribution, geometry, orientation, and concentration,penetration rate of drill bits,rotary speed of drillstring,fluid density.annulus inclination, anddrillpipe position in the wellbore (eccentricity) and axially varying flow geometry. With the advent of deeper drilling and better bit designs, the demand for expending most of the energy at the bit has made it necessary to minimize the pressure losses in the annulus. These pressure losses depend on the fluid velocity, fluid density, and particle concentration. By control of these factors, pressure losses can be minimized. The particle slip velocity is an important factor and is defined as the velocity at which a particle tends to settle in a fluid because of is own weight. The velocity depends on the particle size, its geometry, its specific weight, and fluid rheological properties. The carrying capacity of muds also is affected by the velocity profile in the annulus. With all these variables acting simultaneously, the determination of carrying capacity of a mud becomes a complicated problem. An optimal drilling fluid is expected to lift the cuttings from the wellbore, suspend them when circulation is stopped, and drop them at the surface. Failure to achieve this performance often leads to problems that are costly and performance often leads to problems that are costly and time-consuming to solve. To avoid such problems, the previously mentioned parameters are to be considered in previously mentioned parameters are to be considered in the design of an optimal drilling fluid. Previous Investigations Previous Investigations SPEJ P. 11


Author(s):  
Winarto S. ◽  
Sugiatmo Kasmungin

<em>In the process of drilling for oil and gas wells the use of appropriate drilling mud can reduce the negative impacts during ongoing drilling and post-drilling operations (production). In general, one of the drilling muds that are often used is conventional mud type with weighting agent barite, but the use of this type of mud often results in skin that is difficult to clean. Therefore in this laboratory research an experiment was carried out using a CaCO3 weigting agent called Mud DS-01. CaCO3 is widely used as a material for Lost Circulation Material so that it is expected that using CaCO3 mud will have little effect on formation damage or at least easily cleaned by acidizing. The aim of this research is to obtain a formula of mud with CaCO3 which at least gives formation damage. Laboratory experiments on this drilling mud using several mud samples adjusted to the property specifications of the mud program. Mud sample consists of 4, namely using super fine, fine, medium, and conventional CaCO3. First measuring mud properties in each sample then testing the filter cake breaker, testing the initial flow rate using 200 ml of distilled water and a 20 micron filter disk inserted in a 500 ml HPHT cell then assembled in a PPA jacket and injecting a pressure of 100 psi. The acidification test was then performed using 15% HCL and then pressured 100 psi for 3 hours to let the acid work to remove the cake attached to the filter disk (acidizing). Laboratory studies are expected which of these samples will minimize the formation damage caused by drilling fluids.</em>


Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 327
Author(s):  
Ekaterina Leusheva ◽  
Nataliia Brovkina ◽  
Valentin Morenov

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.


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%.


Author(s):  
Jonathan Kühne ◽  
Frederic Güth ◽  
Heike Strauß ◽  
Yvonne Joseph ◽  
Pál Árki

Modern drill strings for the exploration of oil and gas are equipped with a variety of sensor carrying devices such as Measurement While Drilling (MWD), Logging While Drilling (LWD), and Formation Testing While Drilling (FTWD). These devices generate a large amount of downhole data, such as the orientation of the well, drilling parameters e.g. weight on bit and torque, and formation properties. Appropriate telemetry systems are included in the drill string to transfer relevant downhole data in real time to the surface. Other data is stored in memories downhole for subsequent evaluation. However, drilling fluid properties are still monitored at the surface and their behavior under borehole conditions is predicted with hydraulic models. Commercial solutions for a direct downhole measurement of various drilling fluid parameters are rare, though they would increase drilling process safety and the knowledge about the behavior of drilling fluids under real bottomhole conditions. The pH has a significant influence on the properties of water-based muds and plays a role in the chemistry of oil-based muds as the water cut in the emulsion increases. Commercial pH-sensing devices, such as the glass electrode, and optical sensors are not appropriate for the pH measurement under bottomhole conditions. Fragility, the insufficient degree of miniaturization, the low temperature and pressure resistance due to the liquid reference electrolyte, and phenomena such as the alkaline error are certain drawbacks of glass electrodes. Often optical sensors often will not capture the whole pH scale and require the medium to be at least slightly transparent for light. The usage of pH-sensors based on EIS (electrolyte-isolator-semiconductor) structures is a possible application of chemical sensors for drilling fluid monitoring under in situ borehole conditions. This paper presents results from a study on the behavior of an EIS structure as a pH sensitive electrode measured vs. a commercial Ag/AgCl reference electrode in comparison with a commercial glass electrode. EIS structures are capacitive pH sensors where the sensing layer is generally a metal oxide on a semiconductor substrate. Measurements in basic drilling muds were conducted under constant temperature and atmospheric pressure while the drilling mud was steadily stirred. The mud was titrated from alkaline to acidic conditions with hydrochloric acid and the pH was measured after potential equilibration at the electrodes. The results show a general feasibility for the usage of the proposed sensor. There are still certain challenges to be overcome in the development of a robust and reliable pH-sensing device for complex fluids, such as drilling muds under high pressure/high temperature (HP/HT) conditions.


Author(s):  
Mesfin Belayneh ◽  
Bernt S. Aadnøy

Drilling fluid plays a key role in an efficient drilling operation to minimize problems such as wellbore collapse, circulation losses and stuck pipe. Well instability problems are costly as they increase the non-productive time and the overall budget (1) (2). Well instability problems controlled by designing appropriate mud density and fluid properties that controls the well. The fracture sealing ability of a drilling fluid is one very important of the drilling mud. This paper presents design of water-based drilling fluids and results from laboratory experiments to quantify the loss circulation performance of drilling fluids. Because it is preferable to use oil-based muds in some well sections, the paper will also include a recent study on how to minimize losses when using oil based muds. Here uses of micro/nanoparticles have shown to reduce filtrate losses and to build barriers that are more efficient during circulation loss events. All the tests presented are at low temperature, which is suitable for Artic environments.


Sign in / Sign up

Export Citation Format

Share Document