Experimental Determination of Particle Sedimentation Velocity in Opaque Drilling Fluids

Transcription

1 AADE-14-FTCE-59 Experimental Determination of Sedimentation Velocity in Opaque Drilling Fluid Luila Abib Saidler and Bruno Venturini Loureiro, UCL; André Leibohn Martin, PETROBRAS Copyright 2014, AADE Thi paper wa prepared for preentation at the 2014 AADE Fluid Technical Conference and Exhibition held at the Hilton Houton North Hotel, Houton, Texa, April 15-16, Thi conference wa ponored by the American Aociation of Drilling Engineer. The information preented in thi paper doe not reflect any poition, claim or endorement made or implied by the American Aociation of Drilling Engineer, their officer or member. Quetion concerning the content of thi paper hould be directed to the individual() lited a author() of thi work. Abtract Cutting edimentation velocity i a variable which directly impact hole cleaning and conequently the drilling performance of complex well. The fluid capacity of keeping olid in upenion while the pump are off i alo a critical iue. Thee apect add complexity to the fluid rheology deign, epecially when drilling in narrow operational window cenario. The literature preent extenive experimental tudie in the factor influencing particle ettling in Newtonian and non Newtonian fluid. Mot tudie are focued on viualization technique which are limited to tranparent fluid. Drilling fluid, on the other hand, are generally opaque not allowing edimentation experiment. Correlation developed with tranparent fluid with equivalent rheological profile normally do not reproduce gelation propertie. The preent work preent experimental reult of particle edimentation in non Newtonian fluid obtained by ultra ound meaurement which are compared with reult obtained from image proceing technique. ize, hape and denity effect were evaluated and the comparion of reult indicate good agreement between the technique. Introduction cently one can oberve major evolution of the oil indutry in the Brazilian cenario. Thi evolution provided the breakthrough in thi technological area and conequently the increaing of oil production. Thu, the drilling can be made in vertical or horizontal well, requiring more and more pecific fluid. In the drilling, the fluid i pumped from a drilling unit to the well by a drill tring with a drill at it end. The fluid flow through the interior of column, through drill and return by a void region between the column and the well. The cutting originated in drilling are then tranported by a fluid through the annular region to the urface where it can be eparated from the fluid in the equipment treatment and ent for proper dipoal. The fluid recovered after treated, return to the proce. A the drilling i carried out in everal phae characterized by different diameter drilled, poibly operational arret occur for caing and cementing thi new phae of the well. At thi point, the fluid flow i interrupted and it i neceary for the drilling fluid to become gel to prevent the cutting from precipitating and obtructing the drill, avoiding a collape of the ytem. Currently, drilling fluid conit of complex mixture of olid, liquid and gae. They can aume apect of upenion, emulion or colloidal diperion, depending on the phyical tate of the component. They mut be pecified to promote rapid and afe operation with ome pecial feature [1]. They are indipenable to the drilling tep becaue in addition to it primary function of carrying the generated cutting to the urface, they till cool and lubricate the drill tring and the drill, tabilize the well wall and have the cot compatible with the operation. During the proce of drilling oil well, ediment generated by the drill are formed, known a cutting. The tranport of thee cutting to the urface via fluid ha been the major concern of thi area, ince an inefficient cleaning proce may caue well problem preventing from continuing of the operation. The cleaning of the well depend on fluid parameter (denity, rheology) and proce (edimentation velocity, geometry of the particle, flow). The edimentation velocity i defined a the peed at which the particle ettle within a fluid due to it denity, weight, ize and geometry [2]. To determine the depoition velocity of particle i neceary to know the diameter of the particle, the drag coefficient of the particle and ynold number. Thi work ha a main goal exhibit the ability to determine the edimentation velocity of regular and irregular particle in Newtonian and non Newtonian fluid by the technique of ultraound, comparing it with technique of capturing and proceing image, o it validation can be made. The big motivation for uing thi technique i the opacity baed drilling fluid, motly becaue it doe not allow the ue of the technique of capturing and proceing image for evaluation of the edimentation velocity particle. Theoretical approach According to Ataide et al. [], where a particle of diameter d and denity ρ S fall under the gravity g in a tationary vicou fluid in an infinite medium (neglecting effect of rigid

2 2 L. Saidler, B. Loureiro and A. Martin AADE-14-FTCE-59 boundarie and population or concentration), it move rapidly to achieve balance between three force: buoyancy (F e ), weight (P) and drag (F a ), then reaching a peed contant, called the terminal velocity (ettling velocity). The force acting on the particle are hown in Figure 1. i the vicoity of the fluid. It i known that the edimentation velocity of the phere appear in both the drag coefficient (C D ) a the ynold number (). Thu, an iterative method to obtain the value of thi velocity i required. Haider and Levenpiel [4] propoed a correlation to predict the value of C D for phere, Equation 6, and for irregular particle, Equation 7, which ϕ i the phericity of the particle. Figure 1. Force acting on the accelerated motion of phere in a tagnant fluid. Performing a balance between the force we get: C D 0. ( 1+ 0,1806 ) , ,95 1+ ( 0, , ϕ ) [ 1+ [ exp( 4,0655ϕ )] ] C D 7,69exp ,78exp ( 5,0748ϕ ) ( 6,2122ϕ )... (6) (7) F P F e Fa The mall particle are accelerated rapidly and reach a terminal velocity v t (dv/dt0), where the drag force i balanced by the apparent weight (P Fe), and i called Fa. For a phere move under a fluid in a uniform rectilinear motion, when ΣF 0, the equation of motion become: π Fa 6 ( ρ ρ) gd Even etablihing the equation of motion, Equation 2 cannot obtain the terminal velocity, then being able to ue dimenional analyi to obtain the velocity of edimentation. Dimenional analyi, applied to the tudy of particle dynamic iolated ha the following imilarity condition: C D (1) (2) 2 ρ () f Fr,, ρ Where C D i the drag coefficient; Fr i the number of Froud; i the ynold number and ρ S /ρ i the ratio of the denity of the particle and the denity of the fluid. For thi paper the number of Froud i diregarded due to the greater importance of the ynold number in the ettling proce. The drag coefficient and ynold number are defined from Equation 4 and Equation 5. C D 4 ( ρ ρ) ρ gd v 2 t ρv d t (5) µ Where the d i the particle diameter; v t i the terminal velocity of the particle; ρ i the denity of the fluid and µ (4) The Shape Factor The characterization of a particle by it hape i not eay, due to the difficulty of comparing the irregular form. Knowing how the geometric particle hape influence it edimentation velocity i of the utmot importance for the chemical procee, in particular for cleaning oil well. Wadell [5] introduced a correction factor for the hape of the particle called phericity, defined by Equation 8: ϕ A A p Where: ϕ i the phericity; A i the urface area of a phere of the ame volume of the particle; A i the urface area of the particle. p Thu, phericity i a atifactory criterion to determine the hape of an irregular particle. Table 1, taken from Chhabra and Richardon [6] how variou hape of particle and their phericitie. Table 1. Typical value of phericity. Sphericity Sphere 1 Cube 0,806 Cylinder l/d1 0,87 Cylinder l/d10 0,579 Cylinder l/d20 0,471 Experimental Apparatu and Method The method i divided into two tep. The firt tep conit on determining the geometrical characteritic of the particle and the propertie of the fluid, while the econd conit on determining the edimentation velocity. (8)

3 AADE-14-FTCE-59 Experimental Determination of Sedimentation Velocity in Opaque Fluid Geometric Characterization For the tet with regular particle tainle teel phere (ρs7850 kg/m) and gla (ρs2600 kg/m) with diameter ranging from to 10mm, mooth and pherical, acquired for the experiment were ued. Irregular particle iometric were alo acquired, cube and cylinder, made of teel (ρs7850 kg/m) and aluminum (ρs2700 kg/m), with dimenion varying from to 15 mm. The geometric particle characterization wa performed by meauring the dimenion of each particle with a caliper and the denity of each particle wa determined by calculating the volume and meaurement of their ma. Decription of the Fluid The main Newtonian fluid ued in the experiment wa ilicon oil (ρo980 kg/m) with vicoity about 1000 cst. Thi fluid i uitable for teting ince temperature influence little it vicoity. However, to achieve high ynold number, glycerol olution were alo ued becaue of it low vicoity. A non-newtonian fluid, Carbopol olution were prepared and ued in the tet. Ultraound The method of ultraound conit in generating, tranmitting and amplifying an electrical pule which i converted into the ultraonic pule by a tranducer. The equence of pule form an ultraonic beam that i aligned to another receiving tranducer, the ame pecification a Figure 2. Figure. Screen uperviion of meauring edimentation velocity ultraound ytem. When the particle croe the firt ultraonic beam, the timer tart. Then, when the particle croe the econd ultraonic beam, the timer cloe. Knowing the ditance between the ultraonic beam, and with the value obtained from the peed can be calculated. To validate the technique of ultraound wa neceary to adapt the upervior in Labview to communicate with a CCD camera via trigger, allowing the evaluation of the particle detection by ultraound tranducer and confirmation of the peed of the particle image. In order to enure the meaurement between the tranducer, a tructure wa made of acrylic, o that the ditance between the center of the tranducer were ± 0.05 cm, and can be exemplified by Figure 4. Labview Centralizer Ocillocope Amplifier Ditance Signal generator Tranmitting Tranducer ceiving Tranducer Figure 2. Arrangement of the meauring ytem of the particle ettling velocity. The ultraonic ignal travel through the wall of the acrylic tank with 1.20 m tall and quare edged 0.2 m bae, and run through the fluid reache the enor reception. The receiving tranducer convert mechanical pule into an electrical ignal that i captured by an ocillocope (Agilent 6000 Serie MSO). The ocillocope recorded the wave form converted by the receiving tranducer and end an application developed in Labview, in real time. The experiment by ultraound i all controlled by a upervior in Labview, Figure. Figure 4. Mounting the experiment meauring the ettling velocity by ultraound. In order to obtain a tandard teting procedure 0 phere releae of different diameter, teel and gla, a well iometric particle, cube and cylinder of teel and aluminum have been dropped.

4 4 L. Saidler, B. Loureiro and A. Martin AADE-14-FTCE-59 ult and Dicuion Firt, gla bead and teel were ued to validate the technique of ultraound in ilicone oil and alo in glycerol olution to achieve different value of ynold. The reult of the edimentation velocity of phere by ultraound were compared with thoe obtained by the technique of capture and image proceing. The two technique analyzed howed pherical particle having the ame behavior a hown in Figure 5, allowing validate the ultraound technique according to Equation 6. technique of capturing and proceing image a the technique of ultraound, to make poible a comparion with the literature. The graph of Figure 6 how the reult of the drag coefficient and ynold number obtained by the edimentation velocity of cube obtained by the two technique. It i oberved that the reult achieved by the technique of ultraound are in agreement with the theoretical equation of Haider and Levenpiel [4], Equation 7. Figure 5. Drag coefficient a a function of ynold number for phere of different ize and material. The reult in Table 2 how the average peed acquired by the ultraonic tranducer for 0 releae of each pherical particle. The mean quare error wa calculated in relation to the theoretical peed of each particle, according to Equation 6, proving that the technique of ultraound can determine the ettling velocity of phere with a atifactory error. However, it wa poible to detect that the error i influenced by the velocity of the particle. Thi how that the technique ha a uage limit. Figure 6. Drag coefficient a a function of ynold number for cube of different ize and material. The ame good reult to validate the technique of ultraonic for iometric irregular particle can be oberved for the cylinder according to Figure 7. Table 2. ult of the edimentation velocity of pherical particle by ultraound method. Diameter (mm) Average Speed (cm/) Error Steel,00,491 4,58% Steel 6,5 1,75 5,19% Steel 8,00 20,472 9,45% Gla,00 0,721 7,41% Gla 6,5,274 2,6% Gla 7,9 4,8772,1% Gla 10,0 7,546 4,68% To validate the technique of ultraound for irregular particle, cube and cylinder were cat in ilicone oil and alo in glycerol olution. The velocitie were obtained by both the Figure 7. Drag coefficient a a function of ynold number for cylinder of dimenion and different material. It can be een that a the particle velocity increae, the experimental reult do not match the reult obtained from the literature, which how that the technique i limited to ue alo for irregular particle. With relation to the particle phericity, it i noticed that in low ynold number, the drag coefficient correlation how

5 AADE-14-FTCE-59 Experimental Determination of Sedimentation Velocity in Opaque Fluid 5 little dependence on the particle phericity, the ame reult oberved by Becker [7] in their tudy, and only with 500, approximately, the drag coefficient correlation begin to depend on the phericity of the particle. In order to apply the technique of ultraound in non- Newtonian fluid, ome of Carbopol olution were prepared. The tet were performed by imaging technique and alo by the ultraound technique. Calculating the appropriate ynold number, the reult obtained for olution of phere Carbopol alo howed agreement with the theoretical correlation Haider and Levenpiel (1989), Equation 6, a can be een by the graph of Figure 8. ference 1. Thoma J.E., Fundamento de Engenharia de Petróleo, Interciência, Machado, J.C. ologia e Ecoamento de Fluido Ênfae na indútria do petróleo. Rio de Janeiro: Interciência, Ataide, C.H., Nune, J.F. and Melo, F.R.G. Velocidade terminal de efera em líquido não newtoniano, Congreo Braileiro de Engenharia Química, Curitiba, Haider, A. and Levenpiel, O. Drag Coefficient and Terminal Velocity of Spherical and Nonpherical, Powder Technol. 58, 6, Wadell, H. The coefficient of reitance a a function of ynold number for olid of variou hape, J. Franklin Int., Chhabra, R. P. and Richardon, J. F. Non-newtonian flow and apllied rheology: Engineering Application, 2nd ed., Elevier, H. A. Becker, The effect of hape and ynold number on drag in the motion of a freely oriented body in an infinite fluid, The Canadian Journal of Chemical Engineering, v. 7, n. 2, p , Figure 8. Drag coefficient a a function of ynold number for phere in Carbopol olution. Concluion The experimental reult for regular particle obtained by the technique of ultraound have a high agreement with the theoretical reult obtained in accordance with the correlation of Haider and Levenpiel [4], but the error i influenced by the velocity of the particle. Thi how that the technique i limited to ue for the configuration performed and that require further invetigation to ae wider peed range. Through the reult of irregular particle wa verified that the reult obtained by the technique of ultraound are alo conitent with the literature. The tudy of the edimentation velocity of particle, both regular and irregular, can be further tudied by conidering ome exiting effect in non-newtonian fluid, due to the important application of uch fluid in drilling oil well. A future propoal would invetigate fluid in the preence of fine particulate to oberve it influence on the attenuation of ultraonic ignal and the ettling velocity of particle. Acknowledgment The author of thi tudy thank Petróleo Braileiro S/A - PETROBRAS.