Cuttings-Transport Simulation Combined With Large-Scale-Flow-Loop Experimental Results and Logging-While-Drilling Data for Hole-Cleaning Evaluation in Directional Drilling

2017 ◽  
Vol 32 (03) ◽  
pp. 194-207 ◽  
Author(s):  
Shigemi Naganawa ◽  
Ryosuke Sato ◽  
Masaki Ishikawa
CORROSION ◽  
10.5006/2764 ◽  
2018 ◽  
Vol 74 (8) ◽  
pp. 873-885
Author(s):  
Nicolas Jauseau ◽  
Fernando Farelas ◽  
Marc Singer ◽  
Srdjan Nešić

The entrainment of liquid droplets, occurring in a limited range of gas and liquid flow conditions within the stratified flow region, could represent an effective way to transport a non-volatile liquid corrosion inhibitor through the gas phase and combat top of the line corrosion (TLC). However, such an approach is only viable if the inhibitor can reach the top of the pipe and deposit at a rate higher than the local rate of condensing water can dilute it. This work presents a combined modeling and experimental methodology to determine the onset of droplet entrainment from the bottom and deposition at the top of the line. A modeling approach predicting the droplet entrainment onset is proposed and validated against new multiphase flow data recorded in a large scale flow loop, at operating conditions similar to those encountered in gas-condensate production facilities. Additionally, TLC experiments were performed in the same flow loop under simulated water condensation conditions to measure the actual corrosion at different rates of inhibiting droplet deposition. The results confirm that the droplet entrainment/deposition can effectively mitigate TLC when operating parameters are accurately controlled.


2014 ◽  
Vol 54 (1) ◽  
pp. 329
Author(s):  
Mohammadreza Kamyab ◽  
Nelson Chin ◽  
Vamegh Rasouli ◽  
Soren Soe ◽  
Swapan Mandal

Coiled tubing (CT) technology has long been used in the oil and gas industry for workover and stimulation applications; however, the application of this technology for drilling operations has also been used more recently. Faster tripping, less operational time, continuous and safer operation, and the requirement for fewer crew members are some of the advantages that make CT a good technique for drilling specially deviated wells, in particular, in unconventional reservoirs for the purpose of improved recovery. Cuttings transport in deviated and horizontal wells is one of the challenges in directional drilling as it is influenced by different parameters including fluid velocity, density and rheological properties, as well as hole deviation angle, annulus geometry and particle sizes. To understand the transportation of the cuttings in the annulus space, therefore, it is useful to perform physical simulations. In this study the effect of wellbore angle and fluid rheological properties were investigated physically using a flow loop that has been developed recently for this purpose. The minimum transportation velocity was measured at different angles and an analysis was performed to study the fluid carrying capacity and hole cleaning efficiency. The results indicated how the change in wellbore angle could change the cuttings transport efficiency.


Author(s):  
Evren M. Ozbayoglu ◽  
Flavio Rodrigues ◽  
Reza Ettehadi ◽  
Roland May ◽  
Dennis Clapper

Abstract As explorations advance and drilling techniques become more innovative, complex and challenging trajectories arise. In consequence, cuttings transport has continued to be a subject of interest because, if the drilled cuttings cannot be removed from the wellbore, drilling cannot proceed for long. Therefore, efficient cleaning of highly inclined and horizontal wellbores is still among the most important problems to solve, because these types of wells require specialized fluid formulations and/or specific hole cleaning techniques. There are numerous studies and methods that focus in cuttings transportation in highly inclined and horizontal wells. One of them is the use of viscosity and density sweeps. Sweep pills have been used in the drilling industry as a tool to improve hole cleaning. This report presents the analysis of the performance of different sweeps pills working independently and in tandem in polymeric, oil and synthetic based systems and the comparison between them. The main objective of this project is to provide experimental evidence on which types of fluids perform better under certain conditions by studying the effect of viscosity and density in the bed erosion process in highly inclined and horizontal wells. In order to achieve that, several fluid formulations were tested at different inclination angles (90, 75, 60 degrees) in the Small Indoor Flow Loop property of The University of Tulsa’s Drilling Research Projects. The results of the tests are presented in terms of volume of drilled cuttings removed from the test section and measured differential pressures. All the tests were conducted under atmospheric pressure and ambient temperature. Moreover, a 2-Layer model is used for estimating the erosion performance of sweeps for design purposes, and the model estimations are compared with experimental results. From the experiments, it was identified that polymeric, oil and synthetic based muds with similar density and rheological properties eroded and transported the drilled cuttings similarly under similar test conditions. Furthermore, pumping the sweep pills in tandem demonstrated higher cuttings transport efficiency when compared with the sweep pills applied independently.


2011 ◽  
pp. 1-14 ◽  
Author(s):  
Ali Piroozian ◽  
Issham Ismail

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


Author(s):  
Ekaterina Wiktorski ◽  
Dan Sui ◽  
Kjell Kåre Fjelde ◽  
Vebjørn Langåker

The objective of drilling a well is to prepare a clean hole without obstructions for further casing and production tubing running. Cuttings transport has always been important, but challenging process, especially when drilling long directional wells. Poor hole cleaning causes severe problems, as stuck pipe, extreme torque and drag, difficulties in casing landing, cementing, etc. Extensive studies of cuttings transport, both theoretical and experimental, have been performed to estimate, for example, cuttings concentration and cuttings slip velocity to determine optimal conditions for effective hole cleaning. This paper presents a dynamic analysis of cuttings transport in non-Newtonian fluids based on a transient drift-flux model and an associated numerical scheme AUSMV (advection upstream splitting method) developed by Evje and Fjelde 2002. In this paper, the scheme is modified to simulate cuttings transport dynamically taking into account effects related to pressure, temperature and cuttings slip. During drilling, the heat is transported from the formation into the wellbore and up to the surface. In this paper, the energy balance is enhanced by introducing an analytical temperature model into the AUSMV scheme. The temperature distribution along the well is calculated at the beginning of simulation and kept constant throughout the simulation. Additionally, the AUSMV scheme is improved by considering drilling fluid’s transport- and thermal properties. Transport properties of an oil-based mud, such as viscosity and density, are obtained from experiments. The experimental results were used to determine the coefficients in a linear density model used in the study to investigate the effect of non-Newtonian behavior on the heat transfer, cuttings transport and downhole pressure. Furthermore, a model to calculate the apparent viscosity at various pressures and temperatures was developed based on the experimental results and used to evaluate the impact of viscous forces on the cuttings distribution in the well. Presented numerical scheme solves dynamic cuttings transport problems taking into account the slip velocity variation with wellbore geometry, operational (controllable) parameters and formation properties. In comparison to the traditional steady-state models, the transient cuttings transport model with integrated depth-dependent parameters gives a possibility to achieve a more realistic simulation of cuttings transport, distribution and accumulation along the wellbore through the time.


SPE Journal ◽  
2012 ◽  
Vol 17 (03) ◽  
pp. 912-923 ◽  
Author(s):  
E.M.. M. Ozbayoglu ◽  
R.E.. E. Osgouei ◽  
A.M.. M. Ozbayoglu ◽  
E.. Yuksel

Summary This study aims to investigate the hole-cleaning process during the flow of a drilling fluid consisting of a gas and a liquid phase through a horizontal annulus. Experiments have been conducted using the Middle East Technical University (METU) multiphase flow loop under a wide range of air- and water-flow rates while introducing cuttings into the annulus for different amounts. Data have been collected for steady-state conditions (i.e., liquid, gas, and cuttings injection rates are stabilized). Collected data include flow rates of liquid and gas phases, frictional pressure drop inside the test section, local pressures at different locations in the flow loop, and high-speed digital images for identification of solid, liquid, and gas distribution inside the wellbore. Digital imageprocessing techniques are applied on the recorded images for volumetric phase distribution inside the test section, which are in dynamic condition. The effects of liquid and gas phases are investigated on cuttings-transport behavior under different flow conditions. Observations showed that the major contribution for carrying the cuttings along the wellbore is the liquid phase. However, as the gas-flow rate is increased, the flow area left for the liquid phase dramatically decreases, which leads to an increase in the local velocity of the liquid phase causing the cuttings to be dragged and moved, or a significant erosion on the cuttings bed. Therefore, increase in the flow rate of gas phase causes an improvement in the cuttings transport although the liquid-phase flow rate is kept constant. On the basis of the experimental observations, a mechanistic model that estimates the total cuttings concentration and frictional pressure loss inside the wellbore is introduced for gasified fluids flowing through a horizontal annulus. The model estimations are in good agreement with the measurements obtained from the experiments. By using the model, minimum liquid- and gas-flow rates can be identified for having an acceptable cuttings concentration inside the wellbore as well as a preferably low frictional pressure drop. Thus, the information obtained from this study is applicable to any underbalanced drilling operation conducted with gas/liquid mixtures, for optimization of flow rates for liquid and gas phases to transport the cuttings in the horizontal sections in an effective way with a reasonably low frictional pressure loss.


Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus

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.


Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus

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.


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