The application of gas chromatography fingerprint technique to calculating oil production allocation

Vol. 24 No. 3CHINESE JOURNAL OF GEOCHEMISTRY2005The application of gas chromatography fingerprinttechnique to calculating oil production allocationof single layer in the commingled wellWEN Zhigang(文志刚)2 ,ZHU Dan(朱丹) ,TANG Youjun(唐友军)"2 ,LI Yuquan(李玉泉)2,and ZHANG Guorong(张国荣)*Department of Geochemistry , Yangtze University , Jingzhou 434023 , China2 Key Laboratory of Exploration Technologies for Oil and Gas Resoures ( Yangtze University), .Ministry of Education , Jingzhou 434023 , China3 Department of Geosciences , Petroleum Universily , Beijing 102249 , China” Gudong Oil Production Factory , SLOF , Dongying 257237 , China .AbstractGas chromatography fingerprint technique has the advantages of fast performance and lowcost. It can be used to conduct analysis without interruption either in the field or at laboratory. This tech-nique has been used successfully in such cases that conventional production logging techniques are power-less. Taking low-concentration anthracene as internal standard , we calculated the absolute concentrationsof fingerprints ,initially made some experiments directly on biodegradation of crude oils , and calculatedproduction allocation in the Gudong Oil field. Compared with the production logging , this method hasmade up for the deficiencies of the former GC fingerprint technique. It will find wide applications in moni-toring the trend of production in various oil-fields.Key wordsGC fingerprint technique ; commingled well explotation ; individual level production ; Gu-dong Oilfieldtion results of GC to separate thousands of fractions in1 Principlecrude oils and detect the contents of each fraction sim-ultaneously. Based on this principle , GC analysis wasSince the GC fingerprint technique was first usedcarried out of oil samples from commingled wells in dif-to monitor the production of oilfields by American sciferent reservoirs to discover differences in compoundsentists ( Kaufman and Ahmed , 1990 ; Kaufman et al.in different reservoirs ，i. e. , fingerprint parameters.1987 ) in the 1980s , many researchers have tentativelyThen，under the same GC condition as that underapplied this method in several oil fields( He W enxiangwhich individual-layer oil samples were analyzed , weet al. , 1996 ;2001 ; Wang Zhengping et al. , 2000 ;analyzed oil samples from the commingled wells. WithChen Shijia et al. , 1999 ) and have achieved satisfac-these fingerprint parameters and according to certaintory results. But there appear some obvious deficien-mathematics models , we can accurately calculate thecies in the course of exploration and development.individual-layer production allocation of the commin-Taking anthracene as internal standard , we calculatedgled wells.the absolute concentrations of fingerprints and tenta-tively applied this technique to our experiment on bio-2 Geological backgrounddegradation of crude oils.Some researchers such as Zhou Yuzheng et al.The Gudong Oilfield is located in the northeastern( 2001 ) and England( 1990 ) have found that whenpart of the Zhanhua Sag of the Jiyang Depression in thesamples were collected in the locations away from oil/Bohai Basin , and in the northern part of the Kengu-water and oil/ gas contacts , oils within some continuousreservoirs have a uniform hydrocarbon compositionbord中国煤化工e Qingtaozi Uplift , thewhile oils from separate reservoirs always have measur-nortlHC NMH G, the southeast of theable compositional differences. Although the differ-Zhuangxi Sag and the southwest of the Zhuangdong Sagences are always small , we can make use of the highly(Fig.1).sensitive detector equipped with and the good separa-In the sixth block of the Gudong Oilfield has de-veloped three oil-bearing strata from the bottom up-瓦方数据wards : the Shahejie Formation , the Dongying Forma-258WEN Zhigang et al.Vol. 24tion and the Guantao Formation ，while the main oil-layers54 ,5 ,6' are the chief oil-producing ones ,withbearing stratum is the Upper Triassic Guantao Forma-a possible geological reserve of 1210 x 10* t , account-tion. The layers 5-6 in the upper part of the Guantaoing for 85. 6% of the all possible reserves. The groundFormation have an oil-bearing area of about 5. 7 km2，crude-oil density in layers 54 -6 in the upper part of thewith an average valid thickness of about 7.8 m and a .Guantao Formation is 0. 9628 g/cm° , and the groundpossible geological reserve of 1413 x 10* t. Of those ,crude-oil viscosity is 800 - 1500 mPa' s.Zhuangdong SagChengzikou UpliftChezhen DepressionChengdong Ojfield~Wuhaozhuang ilfibld. Bonan Dilfieltttu angx\ Sath Gudong Ollielpe( rYihezhuang Uplit网Gudao OilfieldZhanhua Depression)Kendong UpliftBonan品Chengjiazhuang UpliftpiveFig. 1. Geological sketch map of the Gudong Oifield.amount of dichloromethane as dissolvent was added ,followed by GC analysis.3 Experimental conditions and calculatingRepetitive research on the GC fingerprint parame-methodsters is a means to examine the stability of GC analysisand also a guarantee of production allocation research.We have carried out repetitive research 4 times in to-3.1 Experimental conditionstal , and the comparative errors are generally within theIn order to ensure the accuracy of detection of va-allowed range of 1% - 5% , which indicates the meth-rious compounds in crude oil samples , we chosed theod is viable.following instruments and reagents after many condi-3.2 Parameter selection and calculating methodtional experiments :For crude oils from the sixth block of the GudongGC analysis was carried out on a SHIMADZUGC-17 Model gas chromatograph equipped with a DB-5Oilfield experienced serious biodegradation , normal al-(50 m x0.25 mm x 0.25 μm ) capillary column andkanes have almost disappeared and only iso-alkanescoupled with a flame ionization detector. Chromato-can be observed. In addition , the concentrations of an-thraq. low and it is preservedgraphie conditions are :spit( 1: 90 ) injection tempera-in中国煤化工is study , we chose an-ture :300C ; nitrogen carrier gas velocity :l mL/min ;thracTYHCNMHGand column initial temperature :459C ( held for 1 minHaving identified more than 400 apices and aboutand then programmed to 3009C at a rate of 4C/ minmore than 500 GC apices , we measured the height ofand held at 300C for 20 min ).Oil samples were put into the instrument directlyeach apex，then calculated the contents of each apexwith anthrs男数据internal standard , and then a lttleaccording to the internal standards. And we have es-tablished the basic fingerprint database consisting ofNo.3Calculate oil production allocation of single layer in the commingled well259the apex numbers , the concentrations of organic com-relative analysis of the fingerprints and the calculationpounds and the sample numbers ( Table 1 ). From theof the production allocation. The parameters selecteddatabase , we chose the parameters which can reflectfrom each well were input into the computer to calcu-differences in individual layers and oil correlations be-late the comparative production allocation of each zonetween the individual layers and the commingled wellsby means of a computer program that was made accord-( Table 2 ) to construct the parameter database for theing to the principle of the least square method.Table 1. Partial data of fingerprint from the sixth block in the Gudong Oilfield36-45532-244328-57533-N144332-53532. 49536-49529- 434Sample No.( μg/g)( ug/g)( μug/g)( μug/g) _Layer No.555545554 556'54556'Apex No.109.4176. 132.1117.559.7146. 280. 979. 8ofGC.2171. 7323. 7161.5112.3258.5118.618. 1172. 2327. 932.7152.094.3251.2119.1133.477.3134.821.991.148.0127.455.268.6 .154. 1219. 657.5172.596.5216.513.5127.892.0122. 946.964.8130.370.393. 9124.0147.291.2152. 891.3169.797.4123.7304. 3.370. 7207. 4359.3223.0398.7234.4347.49176.0222. 4200. 599.2239.6123.4121.71337. 8411.0137.7397.3203. 2166. 1235. !232.0168.4290. 775. 9179.1120.0281. 0.86.3181. 912517.8 .629.7244. 2617.5295.4710. 6363.7387.5312.4393.0252.2374.6238.3405.8224.0328.8107.4136.8129. 5157.266. 890.015134.556.8127.073.0151.370. 2.110.6157.4200.5.66.2177. 6100.7242.0107.3135. 5420.3456.3485. 5315.8555.3299. 2448.118109.5129.072. 378.9153.978. 6128.819178.3304. 697.0178.2129.7277.0108.4229. 82(135.0267.0115. 183.2.228.61.2205.02:750.0750. 0146.9147.364. 6174. 397.6197.169.3148.622215. 6208. 5152.8241.6161.6266.0149.8250.724170.4.211.871.0212.3275.4104. 9180.9103.183.1135. 479. 5165.679.9161.32086.9138. 835.054.0 .135.549.505.8.145. 9161.7173. 695.5210.787. 8191.82883.678.761.454. 5104.653.6106.629144. 0142.2101.1159.197.3176. 291.890.73(48.258.725.561.236. 560.724.172.93163.9156. 0101.0170. 078.0200.232140. 4117. 974. 5142.078.3168.793.9tribution proportions of layer 6' in well 36-495 were4 Results of calculation77.4% ,71.5% and 73.2% , respectively , indicatingthat layer 6' is the chief oil-producing layer in thisIn this study 5 wells were taken for example and awell.discussion was given to the individual-layer productionThe monitoring results for the three single layersallocation of the three main oil-bearing units5+ ,55 andin well 34475 showed : with the respective proportions6' in the Upper Triassic Guantao Formation of the sixthof 18.6%，19.6% and 12.6% , the production allo-block in the Gudong Oilfield.cation of layers_54 and 6' is a lttle larger than that of55,中国煤化工ayer5% is a lttle smal-4.1 Results of calculationler.MH. CNMHG results for well 29-434The results of calculation for the five wells areshowed that It Is simular to well 6-34 475 in oil produc-shown in Table 3. During the three-times monitoring oftion ,that is , in both of them , the contribution propor-well 32-495 and well 32-535 , the oil output of layer 5*tion of layer 6' is a litle larger , while that of layer5S iswas close to that of layer 5’, and the output of layer 54smallest.increased谚数据In three-times monitoring , the con-260WEN Zhigang et al.Vol. 24Table 2. Standard fingerprint parameters for the selected oil wellsWell No.32-53532-49536 49529-434 .Layer No.5455+55556'5456'Fingerprint0.530. 570.684.40parameter1. 191.(0.990. 141.972. 161. 940. 500. 590.49 .0.54.1.491.661. 611.360.710.770.720.760.410.430.422.251.902.860.490. 510.5201. 692.731. 28I10.400.240. 4721.24.751.62.1.183.252. 583.353.65141.011.040.950.810.730.630.650. 82160.320.440.360. 3074.003. 613.813.48180.610. 5691.561.211.521.12200.110.300.090.27217.683. 8010.825.05220.600. 740.460.59.231. 590.971.431.39241.281. 661.31251.471. 221.62260.570.640.55 .271.752.011. 641. 80280.560.590.58292. 672. 903.80300.31310. 534. 40Table 3. Results of calculation of production allocation of individual layers for the commingled wells32. 4953649534 47529 434Sampling time and stratumFirst time( Nov. 2000 )5442.8 %46.7 %39.2 %23.7 %57.2 % .57.3 %22.6 %18.6%16.9 %___77.4 %42.2 %59.4 %Second time( Apr. 2001 )47.3 %51.8 %32.1 %19.9%52.8 %48.2 %28.5 %19.6 %23.6 %/71.5 % .48.3%56.5 %Third time( Sep. 2001 )47.9 %55.6 %41.3 %21.5 %5S52.1 %44.4 %26.8 %12.6 %31.3 %73.2 %43.1 %47.2 %4.2 Comparison with production logging techniquethe中国煤化工ique.MYHCNMHGThe monitoring results for production logging indi-5 Conclusionscated that the oil output of layer 6' is 47. 4% , whilethe output of layers5* and5' is52. 6% in all. This re-The newly developed GC fingerprint technique tosult has proved ,that the oil output of layer 6' is high-calculate the absolute concentrations of fingerprintsest , whickhisireement with the results obtained bywith anthracene as internal standard has advantage overNo.3Calculate oil production allocation of single layer in the commingled well261the traditional GC fingerprint technique. The initial ex-periments on biodegradation of crude oils from the sixthanalysis of commingled wells[ J ]. Petroleum Exploration and Devel-opment. 28 ,82 -83.block of the Gudong Oilfield were done with an attemptKaufman R. L. and Ahmed A. s. ( 1990 ) Gas chromatography as a de-to probe into the production allocation of the commin-velopment and production tool for fingerprinting oil from individual .gled wells ，and satisfactory results have been a-reservoir : Application in the Gulf of Mexico. In GCSSEP Founda-chieved. It is suggested that the newly developed GCtion Ninth Annual Research Conference Proceedings[ C] PP. 263 -fingerprint technique can be widely applied in oil andKaufman R.L. ,Ahmed A.S. ,and Hempkins W.B. ( 1987 ) A tech-gas development.nique for the analysis of commingled oils and its application to pro-duction allocation calculation. In Proceedings of the Sixteenth AnnualReferencesCorention of the Indonessian Petroleum Association[ C] pp. 247 -268.Wang Zhengping , Fu Xiaotai ,Lu Shuangfang , Pang Yanning , Xu Yunt-Chen Shijia , Lin Feng , Chen Xiaofan et al. ( 1999 ) Calculating separaleing ,and Dong Zhonglin( 2000 ) A monitoring technique for produc-zone production of conmingled wells using oil chromalography fin-tion allocation of commingled production well with liquid chromatog-gerprint technique [ J ] Petroleun Exploration and Development.raphy[ J ] Geochimica. 29 , 297 - 301 ( in Chinese with English26 ,63 -71. .England w. A. 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