Effects of temperature and pressure differences on water seepage in breccia

Chin.J.Gcochem.(2012)31:260 -263DOI: 10.1007/s1 1631-012-0574-2Effects of temperature and pressure differences onwater seepage in brecciaXU Longjun , WANG Xingmin'2, and XIAN Xuefu'' State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing Universiy, Chongqing 40044, China2 College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing 400067, China* Corresponding author E-mail: xuj@cqu.edu.cnReceived September 20, 2010; accepted November 1, 2011◎Science Press and Institute of Geochemistry, CAS and Springer. Verlag Berlin Heidelberg 2012Abstract Effects of temperature and pressure differences on water seepage in breccia were investigated by usingthe physicochemical seepage instrument. The results show that the relationship of flow and pressure differences canbe expressed by a linear equation, and the seepage coefficient is linearly correlated with temperature. The relation-ship between seepage flow and temperature could be described with the linear equation. The constant and tempera-ture seepage coefficient showed a linear relation with pressure. Binary quantitative equation for the seepage flow,temperature and pressure was obtained, and explained with experimental data and theoretical analysis.Key words water seepage; pressure difference; temperature; breccia1 Introductionmedia can be classified as the linear and nonlinearseepages. The Darcy law is a basic formula in per-Ore-forming materials are transferred into themeation fluid mechanics. Qi Tian et al. (2007) putinner part of a rock layer through ore-forming fluidsforward a fold line permeation model in the light oftransfusion, forming minerals by thermochemical re-data from the consolidation-permeability combinedaction under the action of microorganisms and crusttest of Xiaoshan clay. The nonlinear transfusion canstress. Pressure of the rock layer and fluid temperaturebe classified as high and low speed permeations. Theare important in the process of ore deposition. Thehigh speed nonlinear transfusion can be describedtransfusion characteristics of high pour point crude inwith the Forchheimer law. Equation of the low speeda fractured petroleum reservoir were examined withseepage is the Darcy law introduced permeability orthe CFS-100 flooding system (Zhang Jianwei et al.,3- parameters model (Deng Ying'er et al, 2003). Re-2009). The results showed that the pressure gradientsearchers proposed the mixture seepage model.linearly increased with increasing flow rate at a con-Namely, the former is nonlinear, and the latter is lin-stant temperature (50, 55, 60, 70 or 80°C). Water headdistribution in the seepage field was obtained by con-Lead and Zn usually exist as the complex com-sidering the mathematic model of 2D steady seepagepounds of metal chloride or the metastable state offield in the fractured network rock mass and the effectmetal sulphate when the ore-forming temperature isof temperature on permeability coefficient (Xu Zeng-higher. The Pb and Zn sulfides are deposited in theguang and Chai Junrui, 2007). The permeability coef-location where there is methane or associated organicficient in the high temperature area was larger thancompound (Hu Ming'an et al., 1983). Pb^+ and Zn'+that in the low temperature area. Water head valuescould be adsorbed when the ore-forming fluid flewinvolving the effect of temperature were generallythrough rocl中国煤化工ed with organichigher than those with no effect of temperature.compoundsMYHC N M H Ge described theEning Pb and ZnSeepage is actually an achieving energy processsulfides (Xuby overcoming resistance. Fluid transfusion in theadsorption characteristics of Pb-+ and Pb *+Zn^+ in thewww.gyig.ac.cn www.springerlink .com空SpringerChin.J.Geochem.(2012)31:260 -263rocks under the static state condition (Xu Longjun etal, 2001, 2002, 2008). In order to understand theautomatically controlled with the sensor. Pressure dif-flowing law and ore-forming mechanism in the rocks,ference was set based on the experimental condition.the effects of temperature and pressure differences onThe sample was put into the sample pot. In orderwater seepage in breccia were investigated.o reduce the effect of water- washing, the iron netcushions were put at the ends of the sample column.2 Materials and methodsK6, K5, K3 and K1 were closed, K2 and K4 wereopened before heating. Water elevated by a pressuri-zation pump was transfused from the sample column,2.1 Samplingand flew into a water tank. The test temperature wasadjusted with a heating control switch. The pressuri-A sample of gray breccia was collected from thezation pump was opened while K2, K1 and K5 wereperipheral rock of a Pb-Zn mine in Yunnan of China.closed. K5 was opened, and K3 and K4 were closed ifThe average chemical components (wt%) of the sam-temperature reached the predicting value. Water pres-ple were respectively CaO(21.32), MgO(1.09), SiO2sure was adjusted with the pressurization control but-(48.55)，Al2O3(4.45)， K20(1.04)， Na20(0.25),ton. Pressure difference was obtained with 2 pressureFeO(0.70), Fe2O3(2.38) and BaO(0.16) (Xu Longjunmeters. Fluid volume was determined through meas-et al., 2002). The porosity of the sample is 3.58%. Theuring glass. Action time of transfusion was also meas-breccia sample was ground and sieved to get -0.833ured.mm-diameter particles. 2.65 kg of circular columnsample was suppressed with a 15 t material experi-3 Results and discussionmental machine. The circular's diameter was 7.93 cm,and the length was 25.2 cm.3.1 Effect of pressure difference on transfusion2.2 ExperimentalThe seepage flow in different temperature andpressure differences is listed in Table 1. As seen fromThe experiments were performed with theTable 1, the seepage flow increases with increasingself-made physicochemical seepage instrument. Thpressure difference at various temperatures. Relation-diagrammatic sketch of the instrument is shown inship between seepage flow and pressure differenceFig. 1. The equipment is composed of a water box, acan be regressed with Equation (1), and the result iscontrol system, a heating system, a pressuring devicelisted in Table 2.K3| tT K6OO1 O2 O3or, O: O:C_BFig. 1. Diagramnatic sketch of the experimental insrument. 1. Indicator lamp; 1'. temp中国煤化工吗courolswich; 3, 3'. pessurization control buton; A sample column; B. water tank; C. pressuriarature sen-sor; F. heaing system; K. two way switch; P pressure meter.FTYHCNMHG.262Chin.J.Geochem.(2012)31:260- -263Table 1 Seepage flow in different differential tempera-ference and d or er can be expressed with Equationtures and pressures (cm3/min)(4)，T(K)290.9299.8309.2 321.24p MPa)0.4038.055.062.0d(er)=A+ B( 0p/p*)(4)0.551.574.587.01150.7566.099.512157where A and B are constants.1.78.016211Table 3 Fitting results of flow velocity and(q/q9)=a+ bp( 0p/p)(1)temperatureParanetererRelative coef-where q" is the standard flow (1 cm2/min), p* is theficientstandard pressure difference (1 MPa), bp represents the-309.01.200.9854pressure seepage coefficient, and a is a constant..55537.72.030.9943There is a linear relationship between seepage flow787.42.940.9996and pressure difference in breccia, instead of the clas-.0-12004.390.9998sical Darcy law.The regressive results are given as follows:Table2 The regressed result of seepage flow andpressure diferenceParameterbpd= 281.08 - 1466(0p/p),r=-0.9984 (5)13.670.990415.08106.40.9918er= -0.905 + 5.252(0p/p),r=-0.9988 (6)309.2-3.000164.10.9995321.2222.60.9931As can be seen in Equations (5) and (6), both dand er are the linear functions of pressure difference.In the light of the data in Table 2, the pressure3.3 Binary quantitative equation for seepage flowseepage coefficient increases with increasing tem-and pressure difference at different temperaturesperature. It is in accord with the research of ZhangXuanqi et al. (2007). In addition, the empirical rela-When Equations (5) and (6) are substituted totion between pressure seepage cofficient and tem-Equation (3), then,perature can be described by Equation (2),(q/q)= 281.1 - 1466( s p/p")bp=-1465.5 + 5.259(T/T9),r= 0.9986 (2)- 0.905(T/r9) + 5.252( s p/p*)(T/T9) (7)where T is temperature, and T' is standard temperatureEquation (7) is a binary quantitative equation for(1 K).seepage flow, pressure difference and temperature.3.2 Temperature and seepage flowFlows in various temperatures and pressure differ-ences can be calculated by using Equation (7). TheThe seepage flow increases with increasing tem-calculated flows are listed in Table 4. Relative errorsperature at various pressure differences from Table 1.could be obtained by comparing the calculated flowsEquation (3) is used for ftting the relation betweenand the measured values in Table 1, and the relativeseepage flow and temperature, and the results areerrors are also listed in Table 4.Most of the relative errors are less than 3% aslisted in Table 3.seen in Table 4. It means that Equation (7) can repre-(q/qh)=d+ er(T17f)(3)sent the effect of temperature and pressure differenceson flow. Yang Hui et al. (2008) thought the tempera-ture field influenced the seepage field in the landfillwhere, d is a constant, and eris the temperature coef-site with each other. Considering that seepage broughtficient of seepage. .about the teif='lowing equation中国煤化工From Table 3, constant d decreases and tempera-can be obtaiture seepage coefficient (er) increases with increasingTHCNMHG(8)pressure difference. The dependence of pressure dif-4T --A(r)va-UyvI.Chin.J.Geochem.(2012)31:260- 263263Table4 Seepage rates and relative errors under different temperature and pressure differences (cem/min)T(K)290.9299.8309.17321.15 .4 (MPa)0.4042.50(11.8%)53.14 (-3.38%)64.3 (3.77%)78.67 (3.51%)0.5551.75 (0.48%)69.41 (6.83%)87.99 (1.14%)11.8 (-2.82%).7564.10 (2.88)99.0(-7.64%)119.5 (-2.02%)155.9 (<0.72%)79.52 (1.95%)18.2 (-0.24%)158.9 (-0.66%)211.0 (0.01%)Note: Values in the brackets represent relative errors.where qr and K(T) are respectively the water flowReferencesflux due to the temperature gradient and the permea-tion coefficient. VH is the change of water head,Deng Ying' er and Liu Ciqun (2003) Mathematical model of two-phase fluidVT is the temperature gradient, and D, is the diffu-nonlinear flow in low-perneability porous media with applicationssion ratio of water flow. This seepage does not satisfy[0]. Applied Mathematics and Mechanics. 24, 1049-1056 (in Chinesethe Darcy law, thus a constant could be added inwith English abstac).Equation (8). Changes between seepage coefficient inHu Mingan (1989) A preliminary evaluation of the mineralization and isunderground water-bearing strata and water tempera-characters on the karst type lead-zinc deposits as exemplified by Jing-ture show that the seepage coefficient basically in-ding, Yunnan Province [U] Earh Science- Journal of China Univer-creases with increasing water temperature (Qi Mei,sity of Geosciences.14, 504- 511 (in Chinese with English abstract).2008). Changes in water head are actual pressure dif-Qi Mei (2008) Analysis of infuence of rechage temperature on the pump-ferences in this test. For the same initial temperature,ing rate of water source well [1 Journal of Shandong University ofthe temperature gradient is directly proportional toScience and Technology (Natural Science). 27. 19- -22 (in Chinesetemperature. Thus, Equation (8) could be revised aswith English abstract).Qi Tian, Xie Kanghe, Hu Anfeng, and Zhang Zhiqing (2007) Laboratorialstudy on non-Darcy seepage in Xiaoshan clay [I]. Jourmal of ZhejiangUniversity (Engineering Science). 41, 1023-1028 (in Chinese withqr =c -(C2 +cjT)(sp)- DrT(8a)English abstract),Xu Longjun, Mu Chuanlong, Xian Xuefu, Liu Chenglun, and Cong Xiaolin(2001) Characteristics of competitive adsorption of Pb3+ and Zn2+ inrock U]. Jourmal of Chongqing University (Nanural Science Editon),where Ci(i=1- -3) is a constant. Equation (8a) indicates24, 38- 40 (in Chinese with English abstract).that water flow flux is linearly related with pressureXu Longjun, Mu Chuanlong, and Xian Xuefu (2002) The adsorption dfferdifference, temperature and their product. So, Equa-ence of Pb*+ and Zn2+ in sandstone and breccia 小Rare Metals. 21,tion (7) is reasonable.56-61. .Xu Longjun, Zhou Zhengguo, Liu Chenglun, and Xian Xuefu (2008) Frac-ta-like adsorption kinetics of Pb2+ in rocks [J]. Chinese Journal ofCeochemistry. 27, 126-129.4 ConclusionsXu Zengguang and Chai Junrui (2007) Numerical analysis of the steadyseepage field in fractured network rock mass considering the efet oftemperature [J]. Journal of Xi'an Shityou University (Natural Science(1) There is a linear relation between seepageflow and pressure difference in breccia, instead of theYang Hui, Ge Weiya, and Dong Zhigao (2008) Study of mathematical modelclassical Darcy law. Relationship between pressureon coupling between temperature and seepage field in landfill site [].seepage coefficient and temperature can be describedSafery and Environmental Engineering. 15, 63- 66 (in Chinese withwith a linear equation.English abstract).(2) The seepage flow increases as temperatureZhang Jianwei, Yang Shenglai, Wang Ljun, Kang Minghui, Yuan Wu, andincreases at various pressure differences, (q/q")= d +Deng Hui (2009) Experimental research on the pressure gradient ofer(T/T).high pour-point oil seepage in fractured oil reservoir [J]. Inner Mon-Relationship between constant d or er and pres-golia Petrochemicul Industry. (4), 77-78 (in Chinese with English ab-sure difference can be fitted with a linear equation.stract).(3) The binary quantitative equation for seepageZhang Xuanqi, Guo Xiaoqing, Yu Ligang, Wen Guo, and Yang Hongflow with pressure difference and temperature is ob-(2007) πmperature-streseepage coupling effct in super-low per-tained, and its rationality has been proved with theo-mability r中国煤化工u Univrsty (Nauralretical analysis and experimental results.Science EdYHCNM HGglish abstract)..