scholarly journals Fundamentals and Physical Principles for Drilled Cuttings Transport—Cuttings Bed Sedimentation and Erosion

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 545
Author(s):  
Camilo Pedrosa ◽  
Arild Saasen ◽  
Jan David Ytrehus
Keyword(s):  
Fluid Velocity ◽  
Drilling Fluids ◽  
Transport Parameters ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Bed Height ◽  
Drilling Optimization ◽  
Rules Of Thumb ◽  
Cuttings Bed ◽  
Physical Principles

The increasing necessity of challenging wellbore structures and drilling optimization for improved hole cuttings cleaning has been growing along time. As a result, operator companies have been researching and applying different hole cleaning techniques. Some of these are applied as traditional rules of thumb but are not always suitable for the new and up-coming challenges. This may result in inefficient hole cleaning, non-productive times, pipe stocking and low rate of penetration (ROP), among other problems. Here are presented some results and improvements for hole cleaning optimization obtained by the different research groups. The different authors mainly focus on specific cuttings transport parameters and sometimes combination of some of them. For this reason, there has not been a study that takes into account all of the different factors at the same time to accurately predict the cuttings bed height, formation and erosion, critical fluid velocity and properties and other key parameters. Consequently, there is a lack of understanding about the relation between different factors, such as the cohesiveness of the drilled cuttings with the different interstitial drilling fluids within the cuttings-bed. This relation can be analyzed establishing a wet-granular approach to obtain more efficient cuttings transport mechanism in challenging conditions.

scholarly journals Wet Drilled Cuttings Bed Rheology

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1644
Author(s):  
Camilo Pedrosa ◽  
Arild Saasen ◽  
Bjørnar Lund ◽  
Jan David Ytrehus
Keyword(s):  
Drilling Fluid ◽  
Drilling Fluids ◽  
Parallel Plates ◽  
Single Particles ◽  
Cuttings Transport ◽  
Transport Studies ◽  
Water Based ◽  
Fluid Properties ◽  
External Forces ◽  
Cuttings Bed

The cuttings transport efficiency of various drilling fluids has been studied in several approaches. This is an important aspect, since hole cleaning is often a bottleneck in well construction. The studies so far have targeted the drilling fluid cuttings’ transport capability through experiments, simulations or field data. Observed differences in the efficiency due to changes in the drilling fluid properties and compositions have been reported but not always fully understood. In this study, the cuttings bed, wetted with a single drilling fluid, was evaluated. The experiments were performed with parallel plates in an Anton Paar Physica 301 rheometer. The results showed systematic differences in the internal friction behaviors between tests of beds with oil-based and beds with water-based fluids. The observations indicated that cutting beds wetted with a polymeric water-based fluid released clusters of particles when external forces overcame the bonding forces and the beds started to break up. Similarly, it was observed that an oil-based fluid wetted bed allowed particles to break free as single particles. These findings may explain the observed differences in previous cutting transport studies.

Development of Digital Twins for Drilling Fluids: Local Velocities for Hole Cleaning and Rheology Monitoring

2021 ◽  
Author(s):  
Mehrdad Gharib Shirangi ◽  
Roger Aragall ◽  
Reza Ettehadi ◽  
Roland May ◽  
Edward Furlong ◽  
...  
Keyword(s):  
Machine Learning ◽  
Rheological Properties ◽  
Drilling Fluid ◽  
Training Data ◽  
Drilling Fluids ◽  
Hole Cleaning ◽  
Digital Twins ◽  
Wide Range ◽  
Drilling Operations ◽  
Cuttings Bed

Abstract In this work, we present our advances to develop and apply digital twins for drilling fluids and associated wellbore phenomena during drilling operations. A drilling fluid digital twin is a series of interconnected models that incorporate the learning from the past historical data in a wide range of operational settings to determine the fluids properties in realtime operations. From several drilling fluid functionalities and operational parameters, we describe advancements to improve hole cleaning predictions and high-pressure high-temperature (HPHT) rheological properties monitoring. In the hole cleaning application, we consider the Clark and Bickham (1994) approach which requires the prediction of the local fluid velocity above the cuttings bed as a function of operating conditions. We develop accurate computational fluid dynamics (CFD) models to capture the effects of rotation, eccentricity and bed height on local fluid velocities above cuttings bed. We then run 55,000 CFD simulations for a wide range of operational settings to generate training data for machine learning. For rheology monitoring, thousands of lab experiment records are collected as training data for machine learning. In this case, the HPHT rheological properties are determined based on rheological measurement in the American Petroleum Institute (API) condition together with the fluid type and composition data. We compare the results of application of several machine learning algorithms to represent CFD simulations (for hole cleaning application) and lab experiments (for monitoring HPHT rheological properties). Rotating cross-validation method is applied to ensure accurate and robust results. In both cases, models from the Gradient Boosting and the Artificial Neural Network algorithms provided the highest accuracy (about 0.95 in terms of R-squared) for test datasets. With developments presented in this paper, the hole cleaning calculations can be performed more accurately in real-time, and the HPHT rheological properties of drilling fluids can be estimated at the rigsite before performing the lab experiments. These contributions advance digital transformation of drilling operations.

Prediction of Cuttings Transport Behavior under Drill String Rotation Conditions in High-Inclination Section

2020 ◽  
Vol 34 (10) ◽  
pp. 2059035
Author(s):  
Shihui Sun ◽  
Jinyu Feng ◽  
Zhaokai Hou ◽  
Guoqing Yu
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Drilling Fluid ◽  
Drill String ◽  
Additional Contribution ◽  
Fluid Viscosity ◽  
Fluid Flow Rate ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Cuttings Bed

Cuttings are likely to accumulate and eventually form a cuttings bed in the highly-deviated section, which usually lead to high friction and torque, slower rate of penetration, pipe stuck and other problems. It is therefore necessary to study cuttings transport mechanism and improve hole cleaning efficiency. In this study, the cuttings-transport behaviors with pipe rotation under turbulent flow conditions in the highly deviated eccentric section were numerically simulated based on Euler solid–fluid model and Realizable [Formula: see text]–[Formula: see text] model. The resulted numerical results were compared with available experimental data in reported literature to validate the algorithm, and good agreement was found. Under the conditions of drill string rotation, cuttings bed surface tilts in the direction of rotation and distributes asymmetrically in annulus. Drill string rotation, drilling fluid flow rate, cuttings diameter, cuttings injection concentration and drilling fluid viscosity affect the axial velocity of drilling fluid; whereas drilling fluid tangential velocity is mainly controlled by the rotational speed of drill string. Increase in value of drill string rotation, drilling fluid flow rate or hole inclination will increase cuttings migration velocity. Notably, drill string rotation reduces cuttings concentration and solid–fluid pressure loss, and their variations are dependent on inclination, cuttings injection concentration, cuttings diameter, drilling fluid velocity and viscosity. However, when a critical rotation speed is reached, no additional contribution is observed. The results can provide theoretical support for optimizing hole cleaning and realizing safety drilling of horizontal wells and extended reach wells.

scholarly journals Cuttings Transport In Horizontal And Highly Deviated Wellbores

2011 ◽  
pp. 1-14 ◽  
Author(s):  
Ali Piroozian ◽  
Issham Ismail
Keyword(s):  
Flow Regime ◽  
Removal Efficiency ◽  
Drilling Fluid ◽  
Fluid Velocity ◽  
Fluid Viscosity ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Drill Cuttings ◽  
Hole Cleaning ◽  
Positive Effect

Lencongan dari laluan tegak menyebabkan rincisan gerudi berkumpul pada bahagian bawah lubang telaga sehingga terbentuknya lapisan rincisan. Akibatnya, berlaku beberapa permasalahan operasi ketika berlangsungnya penggerudian. Daya seret dan kilas yang melampau, kesukaran yang dialami ketika penyorongan rentetan selongsong ke dalam lubang telaga, kesukaran untuk memperoleh operasi penyimenan yang baik, dan lekatan mekanikal paip gerudi adalah antara beberapa contoh lazim yang berkaitan dengan permasalahan terbabit. Sehubungan itu, pemahaman yang baik tentang parameter utama operasi yang mempengaruhi pembersihan lubang telaga adalah penting. Artikel ini mengetengahkan keputusan daripada kajian makmal yang telah dilaksanakan untuk menilai keberkesanan tiga jenis bendalir gerudi dalam menyingkir rincisan gerudi. Kajian makmal melibatkan penggunaan gelung legap aliran sepanjang 17 kaki dengan diameter 2 inci sebagai bahagian ujian. Bagi setiap uji kaji, prestasi pengangkutan rincisan (CTP - Cuttings Transport Performance) ditentukan menerusi pengukuran berat. Keputusan uji kaji dianalisis untuk memperoleh kesan menyeluruh ketiga-tiga parameter operasi, iaitu kelikatan bendalir gerudi, halaju bendalir, dan kecondongan lubang telaga. Kajian terkini membuktikan bahawa penggunaan bendalir gerudi berkelikatan tinggi berupaya meningkatkan CTP jika regim aliran adalah gelora. Walau bagaimanapun, peningkatan kelikatan dalam regim aliran peralihan atau laminar masing-masing mengurangkan CTP secara beransur atau mendadak. Kajian juga menunjukkan bahawa peningkatan sudut kecondongan dari 60° ke 90° memberikan kesan yang positif terhadap CTP. Parameter operasi yang memberikan kesan yang ketara dalam kajian ini ialah halaju aliran, dengan peningkatan kecil yang dialami oleh halaju aliran berjaya memberikan kesan positif yang nyata dalam pembersihan lubang telaga. Kata kunci: Kecekapan penyingkiran rincisan; prestasi pengangkutan rincisan; rincisan gerudi; bendalir gerudi; pembersihan lubang telaga Deviation from vertical path makes drill cuttings to accumulate on the lower side of the wellbore that induces the formation of cuttings bed. Subsequently, relative problems occur while drilling. Excessive torque and drag, difficulties in running casing in hole and accomplishing good cementing jobs and mechanical pipe sticking are few of the classical examples of such problems. Therefore, a comprehensive understanding of influential parameters on hole cleaning seems to be essential. This paper presents results of an experimental study that was carried out to evaluate cuttings removal efficiency of three types of drilling fluid. Experiments were conducted using a 17 feet long opaque flow loop of 2 inch diameter as test section. For each test, the amount of cuttings transport performance (CTP) was determined from weight measurements. Three operating parameters were considered, namely drilling fluid viscosity, fluid velocity, and hole inclination. It showed that the use of high-viscosity drilling fluid improved CTP if the flow regime was turbulent. However, increasing viscosity when flow regime was transient or laminar flow lessened CTP gradually or sharply respectively. It was also revealed that an incremental increase in hole inclination from 60° to 90° has a positive effect on CTP. The most influential parameter in this study was fluid velocity in which a small raise of fluid velocity resulted in a substantial positive effect on hole cleaning. Key words: Cuttings removal efficiency; cuttings transport performance; drill cuttings; drilling fluid; hole cleaning

Experimental Investigation of Friction and Hydraulics in Circular and Non-Circular Wellbores With Oil Based Drilling Fluids

2017 ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Operational Parameters ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Experimental Laboratory ◽  
Drilling Operations

Borehole hydraulics, hole cleaning and mechanical friction are important factors for well planning and drilling operations. Many studies aim to exploit and optimize the effect of different operational parameters. The effect of wellbore geometry on hole cleaning and mechanical friction has so far not received much attention. This paper presents results from experimental laboratory tests where hydraulics, hole cleaning and mechanical friction have been investigated for circular and non-circular wellbore geometries with a relevant oil-based field drilling fluid (OBM). The non-circular wellbore geometry was made by adding spiral grooves to the wellbore walls in order to investigate the effects on cuttings transport and mechanical friction. The study contributes to describe the function and ability of deliberately induced non-circular geometry in wellbores as means to achieve a more efficient drilling and well construction. Improving hole cleaning will improve drilling efficiency in general, and will in particular enable longer reach for ERD wells. Reduced mechanical friction may improve the drilling process and many operations during the completion phase. The laboratory experiments were performed in an advanced flow loop setup reproducing field-relevant flow conditions. The flow loop consists of a 10 m long 4” inner diameter borehole made of concrete. A free whirling rotational string with 2” diameter provides a realistic down hole annular geometry. A field-relevant oil based drilling fluid (OBM) was circulated through the test section at different flow rates. To represent the effect of rate of penetration, synthetic drilling cuttings (quartz sand particles) were injected at different rates through the annulus in the horizontal test section. The test results show that borehole hydraulics and cutting transport properties are significantly improved in the non-circular wellbore relative to the circular wellbore. The effect of the mechanical friction is more complex, yet significantly different for the two geometries.

scholarly journals Investigation: Cutting Transport Mechanism in Inclined Well Section under Pulsed Drilling Fluid Action

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2141
Author(s):  
Xiaohua Zhu ◽  
Keyu Shen ◽  
Bo Li
Keyword(s):  
Drilling Fluid ◽  
Drill Pipe ◽  
Friction Torque ◽  
Drilling Fluids ◽  
Cuttings Transport ◽  
Turbulent Dissipation ◽  
Duty Cycles ◽  
Transport Velocity ◽  
Cuttings Bed ◽  
Conventional Drilling

Due to gravity, drilling cuttings are easily accumulated in an inclined well section, ultimately forming a cuttings bed, which places the drill pipe under strong friction torque. In severe cases, this can cause dragging, stuck drills, and broken drill tools. Because conventional drilling fluids are difficult to prevent the formation of cuttings in inclined well sections, a method of carrying cuttings with the pulsed drilling fluid to improve wellbore cleanness is proposed. Experiments and numerical simulations are conducted to investigate the effects of cuttings bed transport velocity, cuttings size, cuttings height, drill pipe rotation speed, cuttings bed mass, and roughness height. The optimal pulse parameters are determined per their respective impact on cuttings transport concerning varied periods, amplitudes, and duty cycles of the pulsed drilling fluid. Compared to cuttings transport under the conventional drilling fluid flow rate, the pulsed drilling fluid produces the turbulent dissipation rate, increases cuttings transport velocity, and thus improves the wellbore clearance rate.

Experimental Investigation of Friction and Hydraulics in Circular and Non-Circular Wellbores With Oil Based Drilling Fluids

2016 ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Operational Parameters ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Experimental Laboratory ◽  
Drilling Operations

Borehole hydraulics, hole cleaning and mechanical friction are important factors for well planning and drilling operations. Many studies aim to exploit and optimize the effect of different operational parameters. The effect of wellbore geometry on hole cleaning and mechanical friction has so far not received much attention. This paper presents results from experimental laboratory tests where hydraulics, hole cleaning and mechanical friction have been investigated for circular and non-circular wellbore geometries with a relevant oil-based field drilling fluid (OBM). The non-circular wellbore geometry was made by adding spiral grooves to the wellbore walls in order to investigate the effects on cuttings transport and mechanical friction. The study contributes to describe the function and ability of deliberately induced non-circular geometry in wellbores as means to achieve a more efficient drilling and well construction. Improving hole cleaning will improve drilling efficiency in general, and will in particular enable longer reach for ERD wells. Reduced mechanical friction may improve the drilling process and many operations during the completion phase. The laboratory experiments were performed in an advanced flow loop setup reproducing field-relevant flow conditions. The flow loop consists of a 10 m long 4″ inner diameter borehole made of concrete. A free whirling rotational string with 2″ diameter provides a realistic down hole annular geometry. A field-relevant oil based drilling fluid (OBM) was circulated through the test section at different flow rates. To represent the effect of rate of penetration, synthetic drilling cuttings (quartz sand particles) were injected at different rates through the annulus in the horizontal test section. The test results show that borehole hydraulics and cutting transport properties are significantly improved in the non-circular wellbore relative to the circular wellbore. The effect of the mechanical friction is more complex, yet significantly different for the two geometries.

Experimental Study of Cuttings Transport Efficiency of Water Based Drilling Fluids

2014 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Benjamin Werner ◽  
Nils Opedal ◽  
...  
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Cleaning Performance ◽  
Water Based ◽  
Fluid Properties ◽  
Drilling Cost

One important requirement for a drilling fluid is the ability to transport the cuttings out of the borehole. Improved hole cleaning is a key to solve several challenges in the drilling industry and will allow both longer wells and improved quality of well construction. It has been observed, however, that drilling fluids with similar properties according to the API standard can have significantly different behavior with respect to hole cleaning performance. The reasons for this are not fully understood. This paper presents results from laboratory tests where water based drilling fluids with similar rheological properties according to API measurements have been tested for their hole cleaning capabilities in a full scale flow loop. Thorough investigation of the viscoelastic properties of the fluids were performed with, among other instruments, a Paar-Physica rheometer. Improved understanding of the fluid properties relevant to hole cleaning performance will help develop better models of wellbore hydraulics used in planning of well operations. Eventually this may lead to higher ROP with water based drilling fluids as obtained with oil based drilling fluids. This may ease cuttings handling in many operations and thereby significantly reduce the drilling cost using (normally) more environmentally friendly fluids. The experiments have been conducted as part of an industry-sponsored research project where understanding the hole cleaning performance of various oil and water based drilling fluids is the aim. The experiments have been performed under realistic conditions. The flow loop includes a 12 meter long test section with 2″ OD freely rotating drillstring inside a 4″ ID wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal position.

scholarly journals Cuttings Transport Using Pulsed Drilling Fluid in the Horizontal Section of the Slim-Hole: An Experimental and Numerical Simulation Study

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3939 ◽  
Author(s):  
Xiaohua Zhu ◽  
Keyu Shen ◽  
Bo Li ◽  
Yanxin Lv
Keyword(s):  
Numerical Simulation ◽  
Drilling Fluid ◽  
Fluid Velocity ◽  
Cuttings Transport ◽  
Safe Operation ◽  
Horizontal Section ◽  
Transport Distance ◽  
Cutting Velocity ◽  
Cuttings Bed ◽  
Transport Method

Poor transport of cuttings in horizontal sections of small-bore well holes leads to high torque and increases the risk of the drill becoming stuck, reducing its service life and posing a threat to safe operation. Because the conventional cuttings transport method cannot effectively remove the cuttings bed, a transport method using pulsed drilling fluid based on a shunt relay mechanism is proposed. A three-layer numerical simulation model of cuttings transport in horizontal small-bore wells is established. Using both experiments and numerical simulations, the cuttings transport is studied in terms of the moving cuttings velocity, cuttings concentration, and distance of movement of the cuttings bed. By varying the pulsed drilling fluid velocity cycle, amplitude, and duty cycle at the annulus inlet, their effects on cuttings transport are analyzed, and the optimal pulse parameters are determined. The results show that the use of pulsed drilling fluid can effectively enhance the moving cutting velocity and transport distance of the cuttings bed, reduce the cuttings concentration, and improve wellbore cleaning.

Effects of Oil-Based Drilling-Fluid Rheological Properties on Hole-Cleaning Performance

2016 ◽  
Author(s):  
Benjamin Werner ◽  
Velaug Myrseth ◽  
Bjørnar Lund ◽  
Arild Saasen ◽  
Zalpato Ibragimova ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Drilling Fluid ◽  
Drill String ◽  
Operating Conditions ◽  
Wellbore Stability ◽  
Drilling Fluids ◽  
Fluid Viscosity ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning

Drilling fluids play an important role in safe and efficient drilling operations. Wellbore stability, formation integrity, drill string lubrication, and cuttings transport are among their main requirements. The removal of a cuttings bed is one of the major difficulties while trying to keep up a steady drilling progress. Deviated and long horizontal wellbore sections provide challenges not only to the drilling equipment in use, but also to the fluids. Cuttings accumulate easily on the bottom of a wellbore section due to gravity and can therefore reduce hole cleaning efficiency. Cuttings transport is highly dependent on the properties of the drilling fluid. Viscosity, density and gel strength are among the key parameters. Drilling fluids have in general a complex composition with either water or oil as a base substance. Demanding operating conditions, for example high temperature difference from topside to the deep downhole sections or varying shear rates throughout the wellbore, also influence the properties of the fluids during operation. Drilling fluids have to be adapted to all these different drilling situations. The aim of the full project is to compare different water- and oil-based drilling fluids regarding their hole cleaning abilities. As part of the experimental study where drilling fluids are circulated in a 10 m long flow-loop test section with a free-whirling rotating inner drill string, rheological characterization with an Anton Paar MCR rheometer is performed. These measurements include determination of flow properties, yield stress and viscosity-temperature dependence. The results are correlated with the industry standard procedures for the testing of drilling-fluid properties with Fann 35 viscometers (API/ ISO standards). Measurements performed on viscometers at the oil rigs are done to receive fast results in order to control the drilling operation. In contrast, rheometer measurements provide the possibility of a deeper comprehension of the rheological properties of the drilling fluids due to the advanced measurement system. This work presents rheological properties for a typical oil-based drilling fluid commonly used on the Norwegian Continental Shelf, and includes a comparison with two other oil-based drilling fluids based on previously published work. The rheometer results are analyzed in relation to the flow loop experiments and to the viscosity data measured in accordance with the API/ISO specifications. The results from the rheological comparison together with the results from the flow-loop experiments are expected to make an influencing contribution to the question of why various drilling fluids perform so differently in terms of cuttings transport.

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