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.

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 Hydraulics and Cuttings Transport in Circular and Non-Circular Wellbores

2013 ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus ◽  
Pål Skalle
Keyword(s):  
Experimental Study ◽  
Test Section ◽  
Drilling Fluid ◽  
Test Results ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Custom Made ◽  
Experimental Laboratory ◽  
Drilling Operations

Cuttings transport is one of the most important aspects to control during drilling operations, but the effect of wellbore geometry on hole cleaning is not fully understood. This paper presents results from experimental laboratory tests where hydraulics and hole cleaning have been investigated for two different wellbore geometries; circular and a non-circular, where spiral grooves have been deliberately added to the wellbore wall in order to improve cuttings transport. Improving hole cleaning will improve drilling efficiency in general, and will in particular enable longer reach for ERD wells. The experiments have been conducted as part of a research project where friction and hydraulics in non-circular wellbores for more efficient drilling and well construction is the aim. The experiments have been performed under realistic conditions. The flow loop includes a 12 meter long test section with 2″ diameter freely rotating drillstring inside a 4″ diameter wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal and 30° inclined positions. The test results show that borehole hydraulics and cuttings transport can be significantly improved in a non-circular wellbore relative to a circular wellbore. Investigating the cutting transport in non-circular wellbores with available models is even more complex than for circular wellbores. Most drilling models assume circular wellbores, but in reality the situation is often different. Also, it may be possible to create non-circular wellbores on purpose, as in the present study. Such a comparative, experimental study of hole cleaning in different wellbore geometries has to our knowledge previously never been performed, and the results were obtained in a custom-made and unique experimental flow loop. The results and the experimental approach could therefore be of value for any one working with drilling.

Experimental Study of Hydraulics and Cuttings Transport in Circular and Noncircular Wellbores

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus ◽  
Pål Skalle ◽  
Arild Saasen ◽  
...  
Keyword(s):  
Experimental Study ◽  
Test Section ◽  
Drilling Fluid ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Custom Made ◽  
Experimental Laboratory ◽  
Drilling Operations ◽  
Extended Reach Drilling

Cuttings transport is one of the most important aspects to control during drilling operations, but the effect of wellbore geometry on hole cleaning is not fully understood. This paper presents results from experimental laboratory tests where hydraulics and hole cleaning have been investigated for two different wellbore geometries; circular and a noncircular, where spiral grooves have been deliberately added to the wellbore wall in order to improve cuttings transport. Improving hole cleaning will improve drilling efficiency in general, and will, in particular, enable longer reach for extended reach drilling (ERD) wells. The experiments have been conducted as part of a research project, where friction and hydraulics in noncircular wellbores for more efficient drilling and well construction are the aim. The experiments have been performed under realistic conditions. The flow loop includes a 12 m long test section with 2" diameter freely rotating drillstring inside a 4" diameter wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal and 30 deg inclined positions. The test results show that borehole hydraulics and cuttings transport can be significantly improved in a noncircular wellbore relative to a circular wellbore. Investigating the cutting transport in noncircular wellbores with available models is even more complex than for circular wellbores. Most drilling models assume circular wellbores, but in reality the situation is often different. Also, it may be possible to create noncircular wellbores on purpose, as in the present study. Such a comparative, experimental study of hole cleaning in different wellbore geometries has to our knowledge previously never been performed, and the results were obtained in a custom-made and unique experimental flow loop. The results and the experimental approach could therefore be of value for any one working with drilling.

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.

Experimental Investigation of Cuttings Transport With Oil Based Drilling Fluids

2016 ◽  
Author(s):  
Sneha Sayindla ◽  
Bjørnar Lund ◽  
Ali Taghipour ◽  
Benjamin Werner ◽  
Arild Saasen ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Test Section ◽  
Drilling Fluid ◽  
Drill String ◽  
Drilling Fluids ◽  
Atmospheric Conditions ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Flow Rates ◽  
Hole Cleaning

Drilling fluids are very complex and are essential for safe and efficient drilling operations. It is vital for the drilling operator to be able to select an appropriate fluid for each individual well, including the decision of using oil-based or water-based fluids or “muds” (OBM or WBM). In this article we present results from a comparative study of three OBM’s which are based on the same fluid system (Versatec). This work is part of a larger investigation where the main objective is to identify and evaluate the difference in the hole cleaning capabilities of OBM’s and WBM’s with similar viscosity as measured by the API/ISO standards. This paper describes an experimental investigation of cuttings transport using flow loop laboratory tests without and with injected cuttings size particles using various industrial oil based fluids with varying density and viscosity. The flow loop includes a 10 meter long test section with 2″ OD free whirling rotating steel drillstring inside a 4″ ID wellbore made of concrete elements positioned inside a steel tubing. Sand particles were injected while circulating the drilling fluid through the test section. Experiments are conducted at atmospheric conditions, but are otherwise designed to represent downhole conditions as closely as possible with respect to fluid and particle properties, flow rates and geometry. Fluids are tested at different flow rates with and without rotation of drill string, with and without sand injection. This has allowed us to study the effects of flow rate and drill string rotation on hole cleaning capabilities of different fluids. The primary results are pressure drop, steady state sand bed height in a horizontal annulus versus fluid and cuttings rates for rotating and non-rotating drill string and in particular the critical rates for fully suspended flow. The results are interpreted in light of results from laboratory characterization of the same fluids, conducted as part of the same project. The results will increase understanding of the relationship between drilling fluid properties and hole cleaning performance. This will enable the development of improved drilling fluids, both operationally and environmentally. Such know-how will also be important in order to develop more accurate transport models.

Full Scale Flow Loop Experiments of Hole Cleaning Performances of Drilling Fluids

2015 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Sneha Sayindla ◽  
Bjørnar Lund ◽  
Benjamin Werner ◽  
...  
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Base Oil ◽  
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 flow loop laboratory tests without and with injected cuttings size particles using a base oil and a commercial oil based drilling fluid. The results demonstrate the importance of the rheological properties of the fluids for the hole cleaning performance. A thorough investigation of the viscoelastic properties of the fluids was performed with a Fann viscometer and a Paar-Physica rheometer, and was used to interpret the results from the flow loop experiments. 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 10 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 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.

Drilling Fluid’s Cuttings Bed Removal Properties for Deviated Wellbores

2020 ◽  
Author(s):  
Jan David Ytrehus ◽  
Bjørnar Lund ◽  
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 2″ OD freely rotating steel drill string inside a 4″ ID 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 12,25″ and 8,5″ sections. The selected setup provides correct shear rate ranges and equal Reynolds number 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 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.

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.

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.

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