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.

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.

Experimental Investigation of Mechanical Friction and Hydraulics for Liner Drilling and Liner Running

2016 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Knud Richard Gyland ◽  
Arild Saasen
Keyword(s):  
Experimental Investigation ◽  
Friction Coefficient ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Transport Efficiency ◽  
Sand Particles ◽  
Norwegian Continental Shelf

The mechanical friction of liner operations is investigated and compared to what is expected for a conventional drill pipe. In addition the cuttings transport efficiency for realistic conditions is studied. The work is also relevant for running completion strings. This article is based on results from laboratory scale flow loop for drilling applications. Sand particles were injected while circulating the drilling fluid through the test section in some of the tests. The procedures used to conduct the experiments are explained and experimental results and observations are discussed. The drilling fluids and additives in these experiments are similar to those used in in fields on the Norwegian Continental Shelf (NCS). Friction coefficient is calculated from the measured torque for different flow velocities and rotational velocities and the force perpendicular to the surface caused by the buoyed weight of the string.

Cuttings Transport with Foam in Highly Inclined Wells at Simulated Downhole Conditions / Transport urobku wiertniczego przy użyciu piany w silnie nachylonych otworach w symulowanych warunkach w otworze

2013 ◽  
Vol 58 (2) ◽  
pp. 481-494 ◽  
Author(s):  
Jiafu Xu ◽  
Evren Ozbayoglu ◽  
Stefan Z. Miska ◽  
Mengjiao Yu ◽  
Nicholas Takach
Keyword(s):  
Shale Gas ◽  
Drilling Fluid ◽  
Polymer Concentration ◽  
Drill Pipe ◽  
Elevated Pressure ◽  
Drilling Fluids ◽  
Cuttings Transport ◽  
Pressure Losses ◽  
Significant Difference ◽  
Rotary Speed

Along with the rapidly growing demand and development activities in unconventional resources, is the growth of environmental awareness and concerns among the public. Foam, as an alternative to traditional drilling fluid, is gaining more and more momentum in the drilling industry. Drilling with foam can minimize formation damage, water usage, and drag and torque. Foam also costs less and leaves a much smaller environmental footprint than other commonly used drilling fluids, such as synthetic oil-based fluids, when developing vulnerable formations such as shale gas. As drilling in horizontal and near horizontal sections has become very common, and the need for such sections is increasing, it is very important to understand cuttings transport and hole cleaning issues when drilling with foam in such sections. A team from University of Tulsa Drilling Research Projects (TUDRP) conducted a series of experiments focused on studying the effects of change in hole inclination angle from 90 degrees to 70 degrees on cuttings transport with foam under Elevated Pressure and Elevated Temperature (EPET) conditions. This experimental and theoretical study also includes other influential parameters such as foam quality, foam flow rate, polymer concentration and drill pipe rotary speed. We have observed that there is no significant difference in cuttings concentration and frictional pressure losses as inclination changes from 70 to 90 degrees. Also, an increase in superficial foam velocity reduces cuttings concentration within the annulus. Pipe rotation influences cuttings concentration and frictional pressure losses for low quality foams, but does not have a significant effect on high quality foams. A correlation for the cuttings bed area and a computer simulator are developed for practical design and field applications. The predicted results are compared with experimental results from this study and previous studies. The comparison shows good agreement. We believe that the findings of this paper will help designers with the choice of optimal drilling fluid for drilling horizontal wells in unconventional (shale) gas/oil reservoirs.

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.

scholarly journals Simulation of steady-state cuttings transport through a horizontal annulus channel

2019 ◽  
Vol 196 ◽  
pp. 00011 ◽  
Author(s):  
Yaroslav Ignatenko ◽  
Andrey Gavrilov ◽  
Oleg Bocharov ◽  
Roland May
Keyword(s):  
Steady State ◽  
Pressure Gradient ◽  
Yield Stress ◽  
Cross Section ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Axial Flow ◽  
Cuttings Transport ◽  
Rigid Spheres ◽  
Pipe Rotation

The current study is devoted to simulating cuttings transport by drilling fluid through a horizontal section of borehole with an annular cross section. Drill pipe rotates in fixed eccentric position. Steady-state flow is considered. Cuttings are rigid spheres with equal diameters. The carrying fluid is drilling mud with Herschel-Bulkley rheology. Suspension rheology depends on local shear rate and particles concentration. Continuous mixture model with algebraic equation for particles slipping velocity is used. Two hydrodynamic regimes are considered: axial flow without drill pipe rotation and with drill pipe rotation. In the case of axial flow was shown that increasing of power index n and consistency factor k increases pressure gradient and decreases cuttings concentration. Increasing of yield stress leads to increasing of pressure gradient and cuttings concentration. Cuttings concentration achieves constant value for high yield stress and not depends on it. Rotation of the drill pipe significantly changes the flow structure: pressure loss occurs and particles concentration decreases in the cross section. Two basic regimes of rotational flow are observed: domination of primary vortex around drill pipe and domination secondary vorticity structures. Transition between regimes leads to significant changes of flow integral parameters.

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.

New Approaches for Drilling Highly Depleted Reservoir in Deep Water Wells

2021 ◽  
Author(s):  
Ola Mohamed Balbaa ◽  
Hesham Mohamed ◽  
Sherif Mohamed Elkholy ◽  
Mohamed ElRashidy ◽  
Robert Munger ◽  
...  
Keyword(s):  
Deep Water ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Cost Effective ◽  
Drill String ◽  
Drilling Fluids ◽  
Prevention Measures ◽  
Enabling Factors ◽  
Design Changes ◽  
The Mediterranean

Abstract While drilling highly depleted gas reservoirs with a very narrow drilling window, Common drilling methods like utilizing loss of circulation pills, wellbore strengthening materials and managed pressure drilling (MPD) are being used in several reservoirs, yet it cannot be successful or cost effective if applied in a traditional manner. Innovative approaches to enable drilling wells in highly depleted reservoir in the Mediterranean deep water were adopted. The approaches incorporated design changes to the well and Bottom hole assembly (BHA), optimized drilling practices, and unconventional use of MPD while drilling and cementing production liner. Well design change in comparison to offset wells to allow drilling the reservoir in one hole section. Several design changes were considered in the BHA and drilling fluids to prevent as well as mitigate losses and differential sticking risks. From the BHA viewpoint, one of the key successful prevention measures was maximizing the standoff to reduce the contact area with the formation, this was achieved through utilizing spiral heavy wall drill pipe (HWDP) instead of drill collars in addition to a modeled placement of stabilizers and roller reamers. While on the drilling fluid side, Calcium carbonate material was added to strengthen wellbore, prevent losses and avoid formation damage. Particle size up to 1000 micron and concentration up to 40ppb was used to strengthen the depleted sands dynamically while drilling. Furthermore, as mitigation to stuck pipe, Jar and accelerator placement was simulated to achieve optimum impulse and impact force while maintaining the Jar above potential sticking zone. Whereas to address the consequence of a stuck pipe event, disconnect subs were placed in BHA to allow for recovering the drill string efficiently. MPD was first introduced in the Mediterranean in 2007 and continued to develop this well-known technique to mitigate various drilling challenges. For this well, MPD was one of the key enabling factors to safely drill, run and cement the production liner. Surface back pressure MPD allowed using the lowest possible mud weight in the hole and maintaining downhole pressure constant in order to manage the narrow drilling window between the formation pressure and fracture pressure (less than 0.4 ppg). MPD was also applied for the first time for running and cementing the production liner to prevent losses and achieve good cement quality which is a key to successful well production.

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 OIL-BASED DRILLING FLUID'S CUTTINGS BED REMOVAL PROPERTIES FOR DEVIATED WELLBORES

2021 ◽  
pp. 1-9
Author(s):  
Jan David Ytrehus ◽  
Bjørnar Lund ◽  
Mohammad Ali Taghipour ◽  
Luca Carazza ◽  
Knud Richard Gyland ◽  
...  
Keyword(s):  
Test Section ◽  
Field Experience ◽  
Drilling Fluid ◽  
Drill String ◽  
Field Application ◽  
Viscous Fluids ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Frictional Pressure Drop

Abstract Results from cuttings transport tests in laboratory using different field applied oil-based drilling fluids with similar weight and varying viscosities are presented in this paper. The fluids are designed for highly deviated wells, and the cuttings transport performance at relevant wellbore inclinations was investigated. The experiments have been performed in a flow loop that consists of a 10 meters long test section with 50.4 mm (2″) diameter freely rotating steel drill string inside a 100 mm (≈4″) diameter wellbore made of cement. Sand particles were injected while circulating the drilling fluid through the test section. Experiments were performed at three wellbore inclinations: 48, 60 and 90 degrees from vertical. The applied flow loop dimensions are designed so that the results are scalable to field applications; especially for the 12 ¼” and 8 ½″ sections. The selected setup provides correct shear rate ranges and similar Reynolds numbers to the field application when the same fluids are applied. Results show that hole cleaning abilities of the tested fluids vary significantly with well angle, drill string rotation and flow rate. Results support field experience showing that low viscous fluids are more efficient than viscous fluids at higher flow rates and low drill string rotation. As well as per field experience more viscous fluids are efficient in combination with high drill string rotation rates. The results show the effect of cuttings transport efficiency as function of hydraulic frictional pressure drop, demonstrating methods to achieve more optimal hydraulic design in the tested conditions. The key findings have direct relevance to drilling operations.

Steady-State Cuttings Transport Simulation in Horizontal Borehole Annulus

2018 ◽  
Author(s):  
Yaroslav Ignatenko ◽  
Oleg Bocharov ◽  
Andrey Gavrilov ◽  
Roland May
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Flow Structure ◽  
Structural Changes ◽  
Drilling Fluid ◽  
Drill String ◽  
Cuttings Transport ◽  
Horizontal Drilling ◽  
Fluid Properties ◽  
Cuttings Bed

The paper presents the results of modeling the steady-state flow of drilling fluid with cuttings in an annulus for the flow regimes typical for horizontal drilling. The studied parameters include effects like fluid rheology, drillstring rotation and eccentricity on flow regime, pressure drop and cuttings bed. It has been demonstrated that increasing the drilling fluid’s effective viscosity increases the pressure drop, but it decreases the cuttings bed area, while drillstring rotation significantly changes the flow structure, improving cuttings transport and reducing the pressure drop. The considered flow structure can change abruptly due to changed drill string positioning and rheological fluid properties. Such structural changes are followed by abrupt changes in the pressure drop and cuttings bed area.

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