IPTC 16439 New Finding on Heatlo of Superheated Steam Tranmitted Along the Wellbore and Heating Enhancement in Heavy Oil Reervoir Xu Anzhu,SPE, Mu Longxin,SPE,Fan Zifei,SPE,Zhao Lun, Reearch Intitue of Petroleum Exploration and Development, PetroChina Copyright 2013, International Petroleum Technology Conference Thi paper wa prepared for preentation at the International Petroleum Technology Conference held in Beijing, China, 26 28 March 2013. Thi paper wa elected for preentation by an IPTC Programme Committee following review of information contained in an abtract ubmitted by the author(). Content of the paper, a preented, have not been reviewed by the International Petroleum Technology Conference and are ubject to correction by the author(). The material, a preented, doe not necearily reflect any poition of the International Petroleum Technology Conference, it officer, or member. Paper preented at IPTC are ubject to publication review by Sponor Society Committee of IPTC. Electronic reproduction, ditribution, or torage of any part of thi paper for commercial purpoe without the written conent of the International Petroleum Technology Conference i prohibited. Permiion to reproduce in print i retricted to an abtract of not more than 300 word; illutration may not be copied. The abtract mut contain conpicuou acknowledgment of where and by whom the paper wa preented. Write Librarian, IPTC, P.O. Box 833836, Richardon, TX 75083-3836, U.S.A., fax +1-972-952-9435 Abtract At the concluion of everal cycle conventional aturated team huff and puff in heavy oil reervoir, the heating radiu are typically only 20-30m a it went through ucceive aturated team huff and puff. The heating cope can t be enlarged by continuing aturated team huff and puff any more. However, uperheated team huff and puff a a additional heavy oil recovery ignificantly increaed heating radiu of aturated team huff and puff. Conventional aturated team huff and puff theory i not applicable for uperheated team. In thi tudy, uperheat team heat tranmiion mathematical model wa etablihed by three law uch a the law of conervation of ma, the theorem of momentum and the law of conervation of energy, thermodynamic and fluid flow theorie. Baed on model, the parameter uch a temperature, dryne, preure, degree of uperheat, heat lo along the bore were calculated. Thi work analyi the uperior propertie of uperheated team and bring forward uperiority of uperheated team huff and puff to effectively develop heavy oil reervoir in recovery mechanim, including imulation tudie, and current pilot tet effect. Introduction After everal cycle aturated team huff and puff in heavy oil reervoir, the heating radiu are typically only 20-30m, the maximal radiu in perfect reervoir i about 50m [1-3]. In the ultra-heavy oil reervoir, oil aturation tay in original tate out of the heating radiu a it went through ucceive aturated team huff and puff. The heating cope can t be enlarged by continuing aturated team huff and puff any more due to the limited heat carried by aturated team and the eriou heatlo during it tranmiion. In conventional heavy oil reervoir, oil ha a certain capacity of flowing in the original formation. When the reervoir went through tage by depletion or ome cycle aturated team huff and puff, the reervoir preure dropped quickly and formation water wa accelerated to invade in oil reervoir becaue of high oil and water mobility ratio. Watercut increaed rapidly and oil production decreaed harply after water went through bottom hole. The production performance wa becoming wore and wore without changing development method. Thee reervoir were inappropriate for continuing aturated team huff and puff and their propertie probably hardly meet the criteria of aturated team drive.there are huge amount of hydrocarbon accumulation in uch reervoir that can only be exploited with new concept. The econdary enhanced oil recovery technology hould be conidered to improve oil production [3-4]. Whether the aturated team uperheated by the number of temperature degree above aturation temperature would be a a new technology for the recovery of thee heavy oil reervoir. Thi work analyi the uperior propertie of uperheated team and bring forward uperiority of uperheated team huff and puff to effectively develop thee marginal heavy oil reervoir in recovery mechanim, including imulation tudie, and current pilot tet effect.
2 IPTC 16439 Heat tranfer characteritic of uperheated team The intenity of team heat tranfer in the bore and formation i uually meaured by heat tranfer coefficient in thermodynamic. The phyical meaning of heat tranfer coefficient i the unit heat pa through the unit heat tranfer area in the per unit time under 1 o C temperature difference [7]. Obviouly, the greater the heat tranfer coefficient, the more the heat tranfer per unit time. For the team carried a certain quantity of heat, the maller the heat tranfer coefficient, the le heat flow in the unit time, the longer the heat tranfer duration. Table 1 lit the heat tranfer coefficient of different fluid in heat tranfer, which indicate that, when there i phae change of fiuid during the proce of heat flowing will lead to greater heat tranfer coefficient, and no phae change of fluid in heat flowing ha maller heat tranfer coefficient, ga ha the mallet. Figure3 demontrate that uperheated team exit in the region above aturation line (Dryne x=1) and belong to 100% degree of dry ga. The trend of iotherm in Fig.3 how the higher the degree of uperheat i, and the uperheated team i more cloe to ideal ga [10], alo the heat tranfer coefficient i maller. The calculation from Table 2 i that the heat tranfer coefficient i approximately equal to that of air and i only 1/150-1/250 a much a aturated team. In addition, uperheated team ha no phae change in heat tranfer and the heat tranfer coefficient i low.but for aturated team, the lo of heat will caue ome of the team to condene and the phae change occur, heat tranfer coefficient i larger. A i hown from Table 2. According to Newton' law of cooling (Formula 1), the heat flow rate depend on the heat tranfer coefficient, heat tranfer area and the temperature difference. In the ame heat tranfer area, the temperature difference of uperheated team i greater than the temperature difference of aturated team, but the heat tranfer coefficient for uperheated alway i much lower than that for aturated team, the temperature difference i relatively much le than heat tranfer coefficient difference. The higher the degree of uperheat, the lower the heat flow rate, Formula 2 how that, in paing along the ame heat tranfer area, the heat tranfer rate ratio between uperheated team and aturated team i probably equal to the heat tranfer coefficient ratio, That i 1/150-1/250. Superheated team carrie more heat than aturated team, and uperheated team heat lo rate i le than that for aturated team [11]. It can take a relatively long time to cool, during which time the team i releaing very little energy and tranmitted long ditance, which i ueful increae in heating cope. Superheated team can overcome the limitation that after 10 cycle of aturated team timulation, the maximum heating radiu i not enlarged. Q A T T ) Q Q up ( w up A( Tup Tw ) up ( T T T w ) up T (1 A( T T ) ( T T ) T T w w w ) Table 1The value of heat tranfer coefficient Heat tranfer condition value/ W/(m 2 K common ue value /W/(m 2 K Saturated team heated or condened 500015000 10000 Water boiling 100030000 30005000 Water heated or cooling 2005000 4001000 Oil heated or cooling 501000 200500 Superheated team heated or cooling 20100 Air heated or cooling 560 2030 up Synthetic Evaluating Model for uperheated team injection down the bore Aumption of the model foundation are following: (1)Superheated team flow i a contant ma flow in the bore; (2) The bottom of inulated tubing i ealed with packer etting to enure no team into annulu filled with air. (3) The uperheated team flow in the bore i one dimenional teady flow. During uperheated team flow preure and temperature in the ame cro ection are equal everywhere; (4) Heat tranfer from inner urface of the tubing to the outer ring of the cement i teady but from outer ring of cement to formation the heat tranfer i not teady, and the model i built without conidering the heat tranfer in longitudinal direction along the bore. The bore tructure i hown in Figure1.
IPTC 16439 3 uperheated team caing annulu outer tubing heat inulation inner tubing cement Fig.1 bore tructure The mathematical model i founded on the bae of three law(1)the law of conervation of ma (2)The theorem of momentum (3)The law of conervation of energy.equation ued in the calculation are a follow: 1)Ma Conervation Equation Figure 2 Mechanical analyi of micro element Superheated team injection proce i contant ma flow and the ma conervation equation i 2) Theorem of Momentum Equation 1 v A v A 1 2 2 i 2 2 dpa Adzg co v A v A (4) m f Equation 4 decribed uperheated team preure drop along the bore on the bae of analyi of infiniteimal with taking into account the gravity impule, and Adzg co dt i gravity impule within the dt time. The new equation of preure drop dp wa founded by the Theorem of Momentum. 3) Energy Conervation Equation Conidering frictional energy lo in the uperheated team flow, the uperheated team energy equation wa etablihed under the principle of conervation of energy: 2 dq dw dhm d i i i g co dz dz dz dz 2 (3) The phyical meaning of Equation 3 i that the internal energy change of micro element uch a Figure 2 in unit time a a the change of mechanical energy i equal to the heat tranferred to the bore and friction lo. 1 1 m 2 (3) 2
4 IPTC 16439 Equation 3 not only conider the micro body of uperheated team mechanical energy change and the change of their own internal energy and water vapor to the tranfer of heat, but alo conider the team flow proce friction lo of energy dw, can be ued to find out the uperheated team temperature change dt new equation. 4)Auxiliary equation dhm hm dt dhm dp ( ) p ( ) T (4) dz T dz dp dz The equation above can be tranlated into dh dt V dp m C ) } { V T( p (5) dz dz T dz Thi equation i applicable to the all of olid, liquid and gaeou. Functionrelationhipbetweenaturatedteampreureandtemperature t 210.2376 p 0.21 30 (6) Thi equation can determine uperheat degree of team. The mathematical model about uperheated team parameter ditribution along the bore wa etablihed through the Equation1-6. Baic parameter election The parameter uch a team preure, temperature and dryne ditribution along the bore can be calculated by thi mathematical model. In order to compare with aturated team, the tate parameter of uperheated team and aturated team are hown in Table 2. The thermal enthalpy of uperheated team injected into head i 24.81% more than that of aturated team with dryne of 75% from the table. Steam type Table 2 Parameter of differnt team injection Preure MPa Temperature( o C) Dryne(%) Superheat degree( o C) Injection rate(t/h) Enthalpy(kJ/kg) Superheated team 4.00 300 100 49.4 8.00 2962.0 Saturated team 4.00 250.6 75 0 8.00 2373.25 A the team boiler i near the head, the length of uperheated team flow on the ground urface i very hort and i treated a part of bore. Reference bae data for ground pipeline and haft a hown in table 3 Table 3 Parameter of bore tructure Wellbore tructure parameter value Wellbore tructure parameter Value Inner tubing radiu(m) 0.038 Outer tubing radiu(m) 0.04445 thermal conductivity of heat 0.07 urface roughne of tubing (m) inulation tube (W/( m. o C)) 0.0000457 Inner caing radiu(m) 0.0807 Temperature gradient of formation( o C/m) 0.029 Outer caing radiu(m) 0.0889 Thermal Conductivity of formation (W /( m oc)) 1.73 Blackne of inner caing urface 1.0 Thermal Conductivity of cement(w /( m oc)) 0.933 Outer cement radiu(m) 0.213 Coefficient of temperature conductivity of formation (m 2 /h) 0.00037 Ground temperature( o C) 21 Comparion of different team type The tate parameter of uperheated team and aturated team on the head are from Table 2, and the tate parameter for the both uperheated team and aturated team in the bottom are hown in Table 4, the team temperature, preure, dryne ditribution along the bore are hown in Figure 3 and Figure 4 and Figure 5. Table 4 State parameter of uperheated team and aturated team in the bottom
IPTC 16439 5 Steam type preure MPa temperature ( o C) dryne (%) Superheat degree ( o C) enthalpy (kj/kg) heatlo kj/kg Superheated team 3.56 273.97 100 28.8 2896.8 66.15 Saturated team 3.77 247.04 64.06 0 2181.6 191.68 300 290 PreureMPa Temperature 280 270 260 250 240 4.00 3.90 3.80 3.70 3.60 uperheated team aturated team 0 50 100 150 200 250 300 350 depthm Fig.3 Comparion of temperature ditribution along the bore uperheated team aturated team 3.50 0 50 100 150 200 250 300 350 depthm Fig.4 Comparion of preure ditribution along the bore
6 IPTC 16439 100 Dryne% 90 80 70 uperheated team aturated team 60 0 100 200 300 400 depthm Fig.5 Comparion of dryne ditribution along the bore The above calculation reult from Fig.3 how uperheat team ha a ignificant reduction of the uperheat degree after arriving at the bottom but the uperheated team till ha a higher temperature than aturated team with 28.8 o C uperheat degree. Table 4 illutrate heat lo of uperheated team tranmiion along the bore i lower than that of aturated team and the enthalpy value of uperheated team at the bottom i 28. 35% higher than that of aturated team. In addition, after uperheated team reache the bottom, it preure i not necearily higher than the aturated team. A i hown from Fig.4 and Fig.5 indicate uperheated team i alway in the tate of the highet dryne of 100%. Correlation relating different team injection parameter Influence of different team injection preure A i hown from Table 5, uperheated team injection preure are elect uch a 3.5MPa,3.8MPa,4. 0MPa,4.2MPa,4.5MPa. The tate parameter of uperheated team at the bottom hole are hown in table 5. Temperature ditribution along the bore i hown in Figure 6. Tab.5 Superheated team parameter at the bottom under different team injection preure Injection preure MPa Initial enthalpy kj/kg Preure at the bottom Temperature at the bottom Dryne at the bottom MPa () (%) Superheat degree at the bottom Enthalpy at the bottom Heatlo () (kj/kg) kj/kg 3.5 2978.78 2.95 269.8 100 34.9 2910.29 68.49 3.8 2968.63 3.32 272.2 100 30.9 2901.7 66.93 4.0 2961.73 3.56 273.6 100 28.4 2895.7 66.03 4.2 2954.74 3.8 275.0 100 26.1 2889.6 65.14 4.5 2944.07 4.13 277.7 100 23.9 2883.6 60.47 Figure 6 make it clear that with team injection preure increae, uperheated team preure at the bottom hole alo increae and the team temperature keep in pace with the preure. But heat lo decreae gradually with injection preure increae.
IPTC 16439 7 Temperature 305 300 295 290 285 280 275 270 3.5MPa 3.8MPa 4.0MPa 4.2MPa 4.5MPa 265 0 50 100 150 200 250 300 350 depthm Fig.6 Temperature ditribution along the bore under different preure Influence of different team injection temperature A i hown from Table 6, uperheated team injection temperature are elect uch a 280 o C,290 o C,300 o C,310 o C,320 o C,350 o C. The tate parameter of uperheated team at the bottom hole are hown in table 5. Temperature variation along the bore i hown in Figure 7. Table 6 Superheated team parameter at the bottom under different team injection temperature Injection temperature () Initial enthalpy kj/kg Preure at the bottom Temperature at the bottom Dryne at the bottom MPa () (%) Superheat degree at the bottom () Enthalpy at the bottom (kj/kg) Heatlo kj/kg 280 2901.49 3.59 263.2 100 17.5 2861.9 39.59 290 2932.32 3.58 268.4 100 22.9 2878.8 53.52 300 2962 3.56 273.6 100 28.4 2895.7 66.3 310 2989.98 3.54 283.1 100 38.2 2924.5 65.48 320 3017.27 3.52 291.8 100 47.2 2949.9 67.37 350 3094.92 3.48 311.6 100 67.7 3004.7 90.22 Figure 7 make it clear that with team injection temperature increae, uperheated team temperature at the bottom hole alo increae and the team temperature keep in pace with the temperature at the head. But heat lo increae gradually with injection temperature increae.
8 IPTC 16439 360 340 280 290 300 310 320 350 Temperature 320 300 280 260 240 0 50 100 150 200 250 300 350 Well depthm Fig.7 Temperature variation along the bore under different temperature 4 Superiority of Superheated Steam huff and puff A three dimenional imulation model wa built uing CMG STARS and wa tuned with experimental data from the ub-alt oil reervoir. The model conited of a vertical matrix block divided into 18 grid in Z direction, 50 grid block in X direction, and 50 grid block in Y direction. Total matrix block length wa 200m with 18m of width and depth in X and Z direction. The imulation model i homogenou and the parameter are from the log interpretation reult. After a production hitory matching, model recovery factor of 11.3%, the average remain oil aturation wa 57.7%. In order to analyi the effect of different team huff and puff, everal different type of team which carried the ame quantity of heat and had different temperature, dryne and degree of uperheat were injected into the ame oil reervoir under the ame preure of 3MPa. For the firt cycle, the quantity of team injected and cumulative oil production for different team huff and puff were hown in Table 5. Superheated team huff and puff reult in ignificantly greater production. After roughly 700 day of producing, uperheated team huff and puff produced about 150% more oil than that of aturated team. In the uperheated team huff and puff cae, the cumulative oil production i 4050t and the OSR i 1.8 at 700 day. The cumulative oil production i 1463t greater than that of aturated team due to extra oil production aociated with the injection of uperheated team, which reflected the uperiority of uperheated team huff and puff,which wa hown from Table 7. Figure 8 demontrate an important dependence on type of team in that the greater degree of uperheat cae ha greater team override. The heated volume i larger at greater degree of uperheat. Obviouly, the cope of team chamber i controlled by team override. The heat radiu of uperheated team in the firt cycle reached 30m, about 10 meter larger than that of aturated team.
Table 7 Different team carried the ame heat huff and puff effect Temperat dryne Degree of Duration Cyclic Cyclic OSR ure / o C /% uperheat / o C /d injection /t production /t /fraction 236 40 0 700 3716 1713.7 0.46 236 60 0 700 3114 1720.1 0.55 236 80 0 700 2680 1980.6 0.74 236 100 0 700 2352 2587.2 1.10 286 100 50 700 2250 4050.0 1.80 Temperature / o C (a) uperheated team huff and puff baturated team huff and puff Figure 8 ditribution of temperature after the ame heat of different team injection in one cycle 5 RESULTS AND CONCLUSIONS Superheated team exit at the temperature higher than that of it aturated team without the limitation of the preure, which ha a higher temperature, carrie more heat and ha greater heating capacity than aturated team. Superheated team i alway in the tate of the highet dryne of 100%, which determine that it ha a very mall heat tranfer coefficient. In theory, the heatlo of uperheated team during tranmiion in bore i 1/150-1/250 a much a that of aturated team,which mean that much more heat carried to heat oil reervoir and at the ame time it reach further ditance for uperheated team. Under the condition of carrying the ame heat, heating radiu by uperheated team huff and puff i about 10m longer than aturated team. Superheated team huff and puff wa put into Kazaktan heavy oil reervoir after aturated team huff and puff and the average daily oil production wa 2-4 time that of aturated team huff and puff, which improved heavy oil production effectively.superheated team huff and puff a a econdary thermal recovery are very appropriate for difficultly developed heavy oil reervoir. NOMENCLATURE Heat tranferred rate of fluid, w Heat tranferred rate of uperheated team, w Heat tranferred rate of aturated team, w Heat tranfer area, m 2 Temperature of uperheated team, K Temperature of aturated team, K Degree of uperheat, K Temperature of heat tranfer urface, Heat tranfer coefficient of fluid, W/m 2 K - Heat tranfer coefficient of uperheated team, W/m 2 K up -Heat tranfer coefficient of aturated team, W/m 2 K 1 2 Steam denity of into and out of micro element of bore, kg/m 3 Steam denity of all micro element of bore, kg/m 3 m
10 IPTC 16439 v 1,v 2 Steam injection rate of into and out of micro element of bore, m / i Steam ma flow ratekg/ A Area of tubingm 2 p Steam preure of micro element of bore,pa Q Heat tranmiion, W hm Enthalpy of uperheated teamj /kg Trend angle of deviation C Heat capacity at contant preurej/(kg.k) p t Temperature of aturated team, o C p Preure of aturated team MPa z Well depthm REFERENCES [1] Zhang Yitang, Li Xiuluan, Zhang Xia, et al. Four fundamental principle for deign and follow-up of team flooding in heavy oil reervoir [J]. Petroleum Exploration and Development, 2008, 35(6): 715-719. [2] Wu Xianghong*, Xu Anzhu, Fan Hailiang, An integrated evaluation on factor affecting the performance of uperheated team huff and puff in heavy oil reervoir [J]. Petroleum Exploration and Development, 2010, 37(5):608-613. [3] Qu Tongci, Li Shuang. Technique of enhancing recovery of remaining oil in heavy oil reervoir by horizontal [J]. Petroleum Exploration and Development, 2009, 36(6): 743-748. [4] Yan Ke, Ren Huaiqiang. Oil/water inverion and juxtapoition in heavy oil reervoir : Taking 6-7 and member of Guantao Formation, Gudao Oilfield a an example[j]. Petroleum Exploration and Development, 2009, 36(5): 635-640. [5] Hein B, Xie Xiao, Yan Dengchao. New technology for heavy oil exploitation watewater reued a boiler feedwater [J]. Petroleum Exploration and Development, 2008, 35(1): 113-117. [6] Chang Yuwen, Zhang Yi, Hu Yongjiu, et al. The progre of heavy oil thermal recovery technology [M]. Beijing: Petroleum Indutry Pre, 1997. [7] The International Aociation for the Propertie of Water and Steam.IAPWS-IF97 International Formulation 1997 for the Thermodynamic Propertie of Water and Steam [R].Erlangen, Germany, 1997. [8]Rohenow, Warren M, et al. Application of Heat Tranfer Handbook [M]/Book1. Beijing: Science Pre, 1992.102-135. [9] Shen Weidao, Jiang Zhimin, Tong Jungeng. Engineering thermodynamic [M]. Beijing: Higher Education Pre, 2000. 212-229. [10] Li Chuntao, Qian Genbao, Wu Shuhong, et al. The property of uperheated team and it application in the development of heavy oil reervoir: Kenkiyak Oil Field in Kazakhtan a an example [J]. Xinjiang Petroleum Geology, 2008, 29(4): 495-497. [11] Chen Minfeng, Lang Zhaoxin, Mo Xiaoguo. Optimization of team timulation injection parameter and the reaonable development limit of ultra-heavy oi l[j]. Journal of the Univerity of Petroleum, China(Edition of Natural Science), 2002, 26(1): 39-42.