A Comparison of the Density Perforations for the horizontal Wellbore

Transcription

1 Mohammed Abdulwahd, Sadoun Dakhl, Nranjan Kumar A Comparson o the Densty Perorans or the horzontal Wellbore MOHAMMED ABDULWAHID (AUTHOR) Marne Engneerng Department Andhra Unversty Vsakhapatnam INDIA mohw00@yahoo.com NIRANJAN KUMAR Marne Engneerng Department Andhra Unversty Vsakhapatnam INDIA neeru9@yahoo.com SADOUN DAKHIL Fuel & Energy Department Basrah Techncal College Basrah IRAQ drsadoun@gmal.com Abstract: - In ths paper study the low behavor n horzontal wellbore wth 60 and 150 perorans o peroran denstes equvalent 6 and 1 SPF respectvely has been studed. The pressure drops n a perorated ppe that ncludes the nluence o nlow through the ppe walls compares or two ppes that derence n peroran densty. 3D numercal smulans or the ppe wth two numbers o perorans were nvestgated by usng ANSYS CFX modelng ol wth Reynolds number rangng rom 8,773 90,153 and nlux low rate rangng rom lt/hr observe the low through perorated ppe, measure pressure drops. The eect o densty perorans on the low through perorated ppe was conducted. CFD smulans yelded results that are reasonably close experments data. Key-Words: - peroran densty, pressure, numercal, CFX. 1 Introducn In a horzontal well, dependng upon the complen method, lud may enter the wellbore at varous locans and at varous rates along the well length. The complex nteracn between the wellbore hydraulcs and reservor low perormance depends strongly on the dstrbun o nlux along the well surace and t determnes the overall productvty o the well. Thereore, the optmzan o well complen mprove the perormance o horzontal wells s a complex but very practcal and mportant problem. The most commonly used assumpns n studyng horzontal well producn behavor are: nnte conductvty, and unorm nlux. Innte conductvty assumes no pressure drop along a horzontal well, and unorm nlux assumes that the nlux rom the reservor s constant along a horzontal well. It has been argued n the lterature that the nnte conductvty wellbore assumpn s adequate or descrbng low behavor n horzontal wells. Although ths may be a good assumpn n stuans where the pressure drop along the horzontal secn o the wellbore s neglgble compared that n the reservor, t s also reasonable expect the rcn and acceleran eects cause notceable pressure drops n long horzontal wellbores Yuan et al. [1]. The petroleum ndustry started nvestgatng horzontal wellbore was proposed by Ashem et al. [] whch ncluded acceleran pressure loss due contnuous lud nlux along the wellbore. They assumed that the njected lud enters the man low wth no momentum n the axal drecn. Kloster [3] perormed expermental work and concluded that the rcn acr versus Reynolds number relanshp or perorated ppes wth no njecn rom the peroran does not show the characterstcs o regular ppe low. The rcn acr values were 5-70% hgher than those o regular commercal ppes. He also observed that small njecns through perorans reduced the rcn acr. Dnkken [4] presented a smple sothermal model that lnks sngle phase turbulent well low stablzed reservor low. It was proposed that the pressure drop nsde the horzontal wellbore was tally contrbuted by wall rcn. The low n perorated tubes ders rom convennal ppe low as there s radal lud nlow E-ISSN: 4-347X 110 Volume 9, 014

2 Mohammed Abdulwahd, Sadoun Dakhl, Nranjan Kumar through the perorans. The njecn dsturbs the velocty prole and boundary layer Ka et al. [5] such that the pressure gradent along the length o the perorated tube s aected. Boundary layer njecn reduces the rcn o the surace the wetted surace. Ths eect was observed clearly n the transpran experments o Kays [6] and Eckert et al. [7]. The reducn n rcn or transpran experments was propornal or porous suraces snce the average dameters o the surace are sucently small. Yuan et al. [1] the low behavor n horzontal wells wth a sngle peroran and wth multple perorans o peroran denstes equvalent 1, and 4 shots per oot were nvestgated. Experments were conducted wth Reynolds numbers rangng rom 5,000 60,000 and nlux man low rate ras rangng rom 1/5 1/100 or the sngle njecn case and rom 1/100 1/000 or the multple njecn case and or the no nlux case. Horzontal well rcn acr correlans were developed by applyng expermental data the general rcn acr expressons. It was observed that the rcn acr or a perorated ppe wth lud njecn can be ether smaller or greater than that or a smooth ppe, dependng on nlux man low rate ras. Fg. 1- Conguran o partly perorated test ppe (not scale). Table 1- Geometry o the test ppe. Item Ppe 1 Ppe Inner Dameter mm mm Pero. Dameter 4.0 mm 4.0 mm Total number Pero. phasng Pero. densty 6 SPF 1 SPF Model Descrpn Theoretcal analyss was carred out determne the tal pressure drops, rcnal, acceleran and addnal pressure drops wth derent mass low rate and densty perorans. Flud low n a wellbore s consdered as shown n Fg. 1 and assumed an ncompressble, sothermal condn along a unormly ppe. The test ppe s a partly perorated one and the rest s a plan ppe wthout peroran. Ppes and peroran geometry or theoretcal study are lsted n Table 1. The rst one was 60 perorans but the other one 150 perorans wth same dameter. The computanal doman taken up n ths study s same as that o the dmensons consdered n the expermental rgs [8, 9]. The geometry has been analyzed usng 3D Computanal Flud Dynamcs (CFD). Fg. s the structured computanal grds. The calculans were carred out wth commercal nte volume code ANSYS FLUENT 14 CFX solve Naver- Skes equans, usng a rst scheme and turbulent wth k epslon model. Fg. - The unstructured mesh or partly perorated ppe. 3 Smulan Parameters The lud consdered or the smulans s water wth constant densty o 998. kg/m 3 and dynamc vscosty o kg/m s. Three tests were carred out wth Reynolds number o the nlet low rangng rom 8,773 90,153. In each o the tests, low rate through the perorans was ncreased rom zero maxmum value. The roughness o the test ppe wall was 0.03 mm; the type o the test ppe was PVC. Test detals are summarzed n Table. Unorm water mass low s ntroduced at the nlet o a partally perorated ppe. Two boundary condns are consdered. At the nlet mass low s taken n E-ISSN: 4-347X 111 Volume 9, 014

3 Mohammed Abdulwahd, Sadoun Dakhl, Nranjan Kumar consderan both axally and radally where as at the ext outlet pressure s consdered as the boundary condn. It s assumed that no-slp boundary condns occur along the sothermal walls. Water enters at a unorm temperature (T) o 5 C. For the symmetry lnes both velocty and pressure s kept constant. Table - Parameters o partly perorated ppe tests. Test Inlet Flow Rate (lter/hr) Test 1 5,157 5,618 Test 3,361 3,836 Test 3 1,793,318 Peroran nlet Flow Rate (lter/hr) Inlet Flow (Re) ,756 90, ,935 61, ,773 37,198 4 Flud Flow Model or Perorated Secn The pressure drop o the lud n the perorated secn comprsng: a pressure drop caused by the rcnal resstance generated by lud low n the wellbore. Reservor luds low n the well and conluence wth the manstream lud, whch causes the mxed pressure drop p mx.. Meanwhle, radal lud nlow makes well secn become varable mass low, so the acceleran occurs and produces accelerated pressure drop, besdes, there s a pressure drop due p acc. peroran roughness p pero. should be taken n consderan. Dvded the perorated secn n the length o ΔL and the number o n peroran unt accordng the number o holes, each the unt contans a hole. The pressure loss p o unt s obtaned rom the sum o above several pressure loss. p p p p p (1) p wall wall acc. mx. The last two terms n Eq. (1) combne n one term as p add. Equan (1) can be wrtten as: p p p p () wall acc. add. The tal pressure loss o the horzontal wells perorated secns p s stated as ollows: n p T p 1 T (3) Where n s the number o perorated holes. In perorated secn, each unt o wall rcn pressure drop algorthm s the same as the nonperorated secn: p wall 1 The rcn acr L v D can be calculated log Re 3.7D 1.11 (4) (5) When the wall surace nlow and manstream outlow ra (the perorans radal low and wellbore axal low ra) s less than the crtcal value, the radal lud low smooth the ppe low, reduce the pressure drop. At ths pont, the mxng pressure drop caused by the perorans rcn and radal nlow can be wrtten as ollows: p p q 0.031x Re Q mx. (6) Where q s radal low o a sngle peroran, m 3 /s;q s axal low o horzontal wellbore; m 3 /s. Peroran rcn pressure drop can be p obtaned by peroran rcn coecent shown below: p 1 L v d (7) Accelerated pressure drop s only assocated wth the densty o the lud, and the low rate, t can be expressed as: p acc. v 1 v (8) E-ISSN: 4-347X 11 Volume 9, 014

4 Mohammed Abdulwahd, Sadoun Dakhl, Nranjan Kumar 5 Results and Dscusson In ths paper, theoretcally were carred out on the ppes that were smulated wth the expermental ppe 8, 9. Three tests wth derent ppe low rate were carred out or the perorated ppe. Fg. 3 shows the acceleran pressure drop due momentum or three tests. The pressure drop due momentum change (acceleran pressure drop) was calculated rom Eq. 8. The acceleran pressure drop ncreases wth ncrease o the tal low rate ra. We notce at the test 1 when the axal low s large and the radal low s low, there s a small derence between the acceleran pressure drop or the two ppes (60 & 150 perorans) wth ranges rom.95% at zero low rate ra 0.039% at maxmum low rate ra. For test there s a derence n values o acceleran pressure drop wth ncreases o the tal low rate ra wth ranges rom 0.019% at zero low rate 0.164% at maxmum low rate ra. But or test 3 there s a derence wth ranges rom 0.989% at zero low rate ra % at maxmum low rate ra. Because the pressure drop due momentum depends upon the axal veloctes at the nlet and the outlet o the ppe.. Fg. 4 presents the rcnal pressure drop wth tal low rate ra or two ppes (60 & 150 perorans). The rcnal pressure drop ncreases as the low rate ra ncreases or all tests and peroran densty. For test 1 the rcnal pressure drop s greater than tests & test 3. Thereore, the rcnal pressure drop ncreases as the axal low ncreases. The rcn pressure drop ncreases wth decrease the peroran densty.e. the rcnal pressure drop or ppe wth 60 perorans greater than the rcnal pressure drop or ppe wth 150 perorans. The tal pressure drop n a perorated ppe secn s contrbuted by the combned eect o lud mxng and peroran roughness, ordnary rcnal and acceleranal pressure drops. The numercal results were examned n terms o the tal pressure drop wth tal low rate ra, as shown n Fg. 5 or the tests conducted on ppe wth derent peroran densty. The tal pressure drop ncreases as the tal low rate ra ncreases. The tal pressure drop ncreases as ncrease o the peroran densty. Fg. 3- Acceleran Pressure Drop or three tests Fg. 4- Frcn Pressure Drop or three tests Fg. 5- Total Pressure Drop or three tests E-ISSN: 4-347X 113 Volume 9, 014

5 Mohammed Abdulwahd, Sadoun Dakhl, Nranjan Kumar The addnal pressure drop, whch s the combned eects o lud mxng and peroran roughness wth tal low rate ra or 60 and 150 perorans ppes, as shown n Fgs 6 and 7 respectvely. The addnal pressure drop decreases as the tal low rate ra ncreases. Ths shows a lubrcan (smoothng) eect the ppe low by nlow through perorans n the ppe wall. It s demonstrated that the addnal pressure drop due peroran roughness was reduced by the smoothng eect, and that the tal pressure drop was reduced [10]. ppe wth 60 perorans. Ths was because the peroran densty o 150 perorans ppe was twce and hal as larger that o 60 perorans ppe. Fg. 8- Pressure drop coecent or 60 & 150 perorans Fg. 6- Addnal pressure drop or 60 perorans model Fg. 7- Addnal pressure drop or 150 perorans model Eect o peroran densty on the pressure drop coecents o the tal pressure drops s shown n Fg. 8. The pressure drop coecents o ppe wth 150 perorans were obvously larger than those o 4 Concluson Numercal smulans have been carred out on the low n a partly perorated ppe wth nlow through perorans. The geometry o the ppe used was 8, 9, smlar the ppe used n the expermental tests and 10 wth two peroran denstes 60 and 150 perorans. The acceleranal pressure drop or 60 & 150 perorans s small derence n the values or the three tests as shown above because t depends upon the axal veloctes at the nlet and outlet o the ppe. The rcnal pressure drop values or 60 perorans ppe are greater than 150 perorans ppe. The rcn pressure drop ncreases wth decrease the peroran densty. The tal pressure drop ncreases as the tal low rate ra ncreases. The tal pressure drop ncreases as ncrease o the peroran densty. All the addnal pressure drop values or 60 perorans are negatve but some values o 150 perorans ppe are postve. The pressure drop coecent o 150 perorans ppe s larger than 60 perorans ppe. Reerences: [1] Yuan, H., Sarca, C. and Brll, J.P. Eect o Peroran Densty on Sngle Phase Lqud Flow Behavor n Horzontal Wells. Paper SPE 37109, Internanal Conerence on Horzontal Well E-ISSN: 4-347X 114 Volume 9, 014

6 Mohammed Abdulwahd, Sadoun Dakhl, Nranjan Kumar Technology, Calgary, Alberta, Canada, 18-0 November [] Ashem, H. et al.: A Flow Resstance Correlan or Completed Wellbore, J. Petrol. Sc. Eng., 199, 8 (), pp [3] Kloster, J.: Expermental Research on Flow Resstance n Perorated Ppe, Master thess, Norwegan Int. o Technology, Trondhem, Norway (1990). [4] Dkken, B.J.: Pressure Drop n Horzontal Wells and ts Eect on Producn Perormance, JPT (November 1990) 146. [5] Ka H., Fuj, Y., Yamaguch, H. and Myanaga, M. Frcnal Drag Reducn By Injecn Hgh-Vscosty Flud n Turbulent Boundary Layer, Flud Engneerng, June 1993, Vol. 115, pp [6] Kays, W.M. Heat Transer the Transpred Turbulent Boundary Layer, Internanal Journal o Heat and Mass Transer, 15: , [7] Eckert, E.R.G., Lomdard, G., Sparrow, E.M. Experments on Heat Transer Transpred Ppe Flows, Internanal Journal o Heat and Mass Transer, 17: , [8] Su, Z. and Gudmundsson, J.S. Pressure Drop n Perorated Ppes, PROFIT Projected Summary Reports, Norwegan Petroleum Drecrate, Stavanger (1995). [9] Su, Z. and Gudmundsson, J.S.: Pressure Drop n Perorated Ppes, report, Department o Petroleum Engneerng and Appled Geophyscs, U. Trondhem, Norway (1995). [10] Su, Z. and Gudmundsson, J.S.: Peroran Inlow Reduces Frcnal Pressure Loss n Horzontal Wellbores, J. Petrol. Sc. Eng., 1998, 19, pp E-ISSN: 4-347X 115 Volume 9, 014