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Oil source of reservoirs in the hinterland of the Junggar basin

Oil source of reservoirs in the hinterland of the Junggar basin Petroleum Science 2007 VolA NoA Li Wei Zhang Zhihuan", Yang Yongcai' and Meng Xianlong' ,2, (1. International Petroleum Exploration and Production Company, Sinopec, Beijing 100083, China) (2. Key Laboratory ofHydrocarbon Accumulation, Ministry ofEducation, China University ofPetroleum, Beijing 102249, China) (3. West China Branch ofInstititute ofExploration and Development, Sinopec, Urumqi, Xinjiang 830011, China) Abstract: Through oil-oil and oil-source correlation and combined with the comprehensive study of hydrocarbon generation and accumulation history, the oil sources of typical reservoirs of different geologic periods in the hinterland of the Junggar basin are revealed. It is concluded that the crude oils in the study area can be classified into four types: The oil in the area of well Zhuang-l and well Sha-l belongs to type-I, which was generated from Cretaceous to Paleogene (K-E) and its source rocks are distributed in the Fengcheng formation of the Permian in the western depression to the well Pen-I. The oil in the area of well Yong-6 (Kltg) belongs to type-II, which was generated from Cretaceous to Paleogene and its source rocks are distributed in the Wuerhe formation of the Permian in the Changji depression. The oil in the area of well Yong-6 (J2x) belongs to type-III, which was generated at the end of the Paleogene and its source rocks are distributed in the coal measures of the Jurassic in the Changji depression. The oil of well Zheng-l and well Yong-l belongs to type-IV, which was generated in the Paleogene, and its source rocks are distributed in the Wuerhe formation of the Lower Permian and coal measures of the Jurassic. It is indicated that the hydrocarbon accumulation history in the study area was controlled by the tectonic evolution history of the Che-Mo palaeohigh and the hydrocarbon generation history of well Pen-l in the western depression and Changji depression. Key words: Oil source correlation, hydrocarbon accumulation history, Che-Mo palaeohigh, Junggar basin 1. Introduction 2. Geological background In recent years, many new oil fields have been The Junggar basin is located in the northern part of discovered in the hinterland of the Junggar basin, Xinjiang Uygur Autonomous Region, China, in an area showing great oil-prospecting potential. Previous of about 1.3 X 10 km'. The Junggar basin is a large set studies revealed that the Permian formations are the of superposed basins of different characteristics, which most important oil source rocks in the hinterland of the were developed in the late Palaeozoic, Mesozoic and basin (Wang and Kang, 1999). Moreover the Jurassic Cenozoic, and located at the junction of the Siberia, coal measures strata in the hinterland of the basin had Tarim and Kazakhstan blocks. It was developed on the excellent potential as hydrocarbon source rocks (Wang Junggar terrain, consisting of Precambrian crystalline and Jiang, 1995), and the crude oils of the Qigu oil field basement in the upper part and slightly metamorphic in the south Junggar basin and the crude oils of the Palaeozoic basement in the lower part. Cainan oil field in the east Junggar basin have been During the Permian, in the stage of foreland basin, proved to be derived from the source rocks in the the western depression to the well Pen-l and Changji Jurassic (Wang and Lan, 1994; Guo, et al., 2005). depression were developed, which was an important The study area is located in the desert, the hinterland period of source rock formation (Luo, et al., 2000; Wu of the Junggar basin. Previous work showed that the and Ma, 2003). At the end of Xishanyao formation complexity of tectonic evolution in this area led to deposition in the Middle Jurassic, the Junggar basin reservoir formation from multi-sources in multi-phases evolved to a compresso-shearing structure environment (Zou, et al., 2005). So it is difficult to correctly identify and a giant northeast-southwest oriented Che-Mo oil source rocks only through oil-source correlation. By palaeohigh (from Chepaizi uplift to Mobei uplift) was using various geochemistry analysis techniques for formed in the hinterland of the basin. The Che-Mo reservoirs and combined with the study on hydrocarbon palaeohigh still kept the east-west oriented anticline generation history of source rocks, this paper shape in the Cretaceous. However it was tilted by the investigates the main oil sources of typical reservoirs of Himalayan movement (Fig. I) and the palaeohigh different geologic periods in the study area and disappeared and the present large slope was formed (He, discusses whether or not the Jurassic coal measures et al., 2005). strata contributed to the reservoirs. The study area, including Block I and Ill, is located VolA NoA Oil Source of Reservoirs in the Hinterland of the Junggar Basin N----------. S Well Zheng-I Well Zhuang-l Well Zheng-l Well Zhuang-l 0 +-------==------I---......,j.,=---~ K,tg o J,x J,x r-- -t-- J,s ~ 500 if 500 r-- ir J,b '" (b) (a) Well Zhe~g-I Well Zhuang-I WellZheng-1 WellZhuang-1 N,s +-------+----+----1 K,d K,d if if 0- 0- 2000 1500 K,tg a '" a '" J,x J,s J,b (e) (d) Well Zheng-I Well Zhuang-I Well Zheng-I Well Zhuang-I N,s 1000 2000 K,d if 0- t 3000 a '" '" Kitg J,x 4000 J,s J,b (f) (el Fig. I Tectonic evolution history of Che-Mo palaeohigh in the central depression region in the hinterland of the 3. Samples and analysis methods Junggar basin. The main body of the study area is Samples, including crude oils, sandstones, located in a large slope from the western part of the mudstones and coals, were collected from J 1S Changji depression to the western depression to the (Sangonghe formation in the Jurassic) in well Zhuang-l, west of well Pen-l (Fig. 2) and bounded by the well Sha-I and well Zheng-I of central block I, and J 2x Dabasong uplift in the north and by the piedmont (Xishanyao formations in the Jurassic) and Kjtg fault-bench belt on the south margin of the Junggar (Toutunhe Formation in the Cretaceous) in wells Yong-I, basin in the south. The Jurassic and Cretaceous are the Yong-2 and Yong-6 (Fig. 3). main prospecting targets in the study area. Petroleum Science 36 2007 G Well IS:] Boundary line of Junggar basin ~ Fault [j£] Study area Q Boundary line ofteetonic units [[] Yad5 section o 20 40 60(km) I I ~. ~. " .. --_. __ .__ .__ . __ ._-'............. ~~. Sikeshu depression " ~ t--t--,J-"r-::...,Yon -! . - .~ - . _ r'->'~---i+--"" o·ng:.ft·- CD Western depresion to Well Pen-I ® Changji depression Piedmont fault-bench belt ® Dabasong uplift ® Zhongguai uplift Qigu oil field @ Maqiao uplift ® Mobei uplift • Fig. 2 Tectonic units and well locations in study area Well Yong-l D~l;tit Lithostrata K,tg K,tg K,tg ~= • J,x 5960B 600~1BJ J,x J,x 6040t:= liS EB Fine sand Ea Silty sand ~ Shaly sand~ Mudstone _ Coal • Sample Fig. 3 Generalized stratigraphy of the Jurassic and Cretaceous reservoirs and sampling sites Rock samples were powdered and sieved through a oven was initially set at 80°C for 1 min, then sieve (60 mesh) and then were extracted in a Soxhlet programmed to 250°C at 3.5 °C/min and to 300°C at 2 apparatus with methylene chloride for 24 hours. The °C/min, finally it was held for 15 min. extract and crude oil were fractionated on a neutral Fluid inclusions were observed with a Leica DMRXP microscope and the oil-bearing inclusions alumina chromatographic column into saturates, were distinguished by UV fluorescence. The aromatics and a polar fraction, by sequential elution with n-hexane, toluene and chloroform. Gas homogenization temperatures of aqueous inclusions chromatograph-mass spectrometer (GC-MS) analysis of were measured on a Linkam 3500 heater. We followed the techniques of Pan, et al. (2003) to prepare the saturates and aromatics fractions were carried out on a Thermo-Finnigan Trace-DSQ GC-MS Detector. The GC samples and to analyze the compositions of their oil VolA NoA Oil Source of Reservoirs in the Hinterland of the Junggar Basin 37 pristane to phytane (PrlPh) is in a range from 1.0 to 1.5; inclusions. (2) Tricyclic terpanes are in relatively high abundance, 4. Results and discussion the relative abundance of C C or C -tricyclic 20-, 21-, 23 terpanes increases in tum, and the gammacerane index 4.1 Oil-oil and oil-source correlation (gammacerane/Co-hopane) and Ts/(Ts+Tm) are 0.30 According to the distribution and composition of biomarkers, crude oils in the study area can be classified and 0.32 respectively on average; (3) The abundance of into four types. pregnane and homopregnane is relatively high, the The type-I oil is mainly from Jrs in well Zhuang-l relative abundance of C - , C or C regular steranes 27 28-, 29- and well Sha-l. The compositional characteristics of also increases in tum; (4) The abundance of p-carotane bio-marker are as follows (Fig. 4): (1) The ratio of is very high. m/z:191 m/z:217 m/z: 125 m/z:85 , oH C C 'IIIIIII.IIIJ I H R - earrotane II1II I I c 23 JrlL~,elll Sha-I (J, ) Tm P Ts G I Hp ~l~ J _ ~~.~~v·'· :ti B -ea rotane Type-l Type-II Type-Ill Type-IV 11111111·111 ~~ot_an.Leill<l1WIol»l;J.lJ.J..LLLLLJ..UJ...J....c.. Fig.4 Mass chromatograms of oils from J J and k.tg reservoirs in study area 1s, 2x • C20-C tricyclic terpanes; C30R C30-hopane; P: pregnane; HP: homopregnane; G: gammacerane 23• The oil from Kjtg of well Yong-6 belongs to The type-I oil and source rock from the Fengcheng type- II. The compositional characteristics of biomarker formation of the Permian (Pjf) have similar distribution are as follows (Fig. 4): (1) The ratio of pristane to patterns of biomarkers as indicated by the significant phytane ranges from 0.7 to 0.9; (2) Tricyclic terpanes overlapping on the plots of homohopane are in relatively high abundance, and the relative index-C35/(C31+C32+C33+C34+C35) and C 201C21-tricyclic abundance of C terpanes is higher than that terpane, gammacerane index and C 23/C21-tricyclic 2l-tricyclic of C or C terpanes, and the gammacerane terpane ratio (Fig.5-a, b). However the ratio of pristane 20- 23-tricyclic index (gammacerane/Cjs-hopane) and Ts/(Ts+Tm) are to phytane of the Permian source rocks extracts is 0.8 respectively 0.65 and 0.51 on average; (3) The on average, lower than that of the oil. Petroleum Science 38 2007 0.14 + Prf mudstone 0.6 + P,f mudstone • Piw mudstone • Piw mudstone EJ '" 0.12 '" Oils in Well Sha-l (J,s) '" Oils in Well Sha-l(J,s) + .g 0.5 o Oils in Well Zheng-l(J,s) o Oils in Well Zheng-I(J,s) ] 0.10 <> Oils in Well Zhuang-I(J,s) .~ 0.4 <> Oils in Well Zhuang-l(J,s) s: '" + ~ 0.08 ~ 0.3 .8 "" 0.06 I. ~D I / ~ 0.2 ~ 0.04 '" o 0.1 :r: 0.02 0.00 -t--....,---,--r--,...---,----, 0.0 -r----.,....----,.------,-----, 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0.0 0.5 1.0 1.5 2.0 C,jC,,-tricyclic terpane C,/C" -tricyclic terpane (a) (b) 0.14 1.0 + Oils in Well Yong-6(k,tg) :. 0.12 • J coal ~ 0.8 • Prw mudstone '" ] 0.10 '·· - Pif mudstone ~ t;; 0.6 g 0.08 •• a ], + Oils in Well Yong-oik.tg) .2 0.06 + Oils in Well Yong-6(6035m) ~~ 0.4 x Oils in Well Yong-2(5056m) \. +' +. ·1 § 0.04 u • J coal J 0.2 :r: 0.02 • Psw mudstone • • ·1 - Pif mudstone 0.00 -t--......--r----.-----,--,.---, 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0.2 OJ 0.4 0.5 0.6 0.7 C"fC,,-regular sterane C"fC sterane 29-regular (c) (d) 1.2 4.5 + Oils in Well Yong-6(k,tg) '" Oils in Well Yong-lt.l.x) + Oils in Well Yong-6(k,tg) 4.0 o Oils in Well Yong-2(6000n1) o Oils in Well Yong-2(600Om) <> Oils in Well Yong-I(J,s) 1.0 + Oils in Well Yong-6(6035m) - J coal '" Oils in Well Yong-It.I.x) 3.5 +x o Oils in Well Yong-I(J,s) x Oils in Well Yong-2(5056m) 3.0 ? 0.8 Third + Oils in Well Yong-6(6035m) ~ 2.5 x Oils in Well Yong-2(5056m) aD Fouth '" J 0.6 • Second 2.0 + - J coal o '" } 0.4 1.5 1.0 0.2 0.5 0.0 -r---..---,---,---,-----, 0.0 -r---..---..---..---.,....------, 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Gammacerane/Cj.- hopane Gammacerane/Cj.- hopane (e) (\) Fig.5 Distribution of biomarker composition of four types oil *C f(C + C26): C C terpane) 24 24 24-tetracyclicf(C 24-tetracyclic+ 26-tricyclic abundances of pregnane and homopregnane are C terpanes decreases III tum, with 23-tricyclic relatively high, the relative content of C - , C - or gammacerane index being 0.03 on average; (3) The 27 2S C steranes also increases in tum, and the relative abundance of pregnane and homopregnane is 29-regular abundance of C steranes is relatively high; (4) relatively low, and C steranes is predominance, 27-regUlar 29-regular The abundance of B-carotane is very high. but the abundances of C - and C - regular steranes are 27 28 The biomarker composition of the type-II oil is very low; (4) It does not contains B-carotane. The similar to the source rock from the Wuerhe formation of biomarker composition of type-III oil shows typical the Permian (P and it can be seen from the characteristics of coal-generated oils. GC-MS analysis 2w), distribution pattern of C - , C - and C tricyclic showed that the geochemical characteristics of the oil 20 2 1 23 terpanes and the pattern of C - , C - and C biomarker and of hydrocarbon source rock from coal 27 2S 29-regular steranes (Fig.5-c, d). f), measure strata in the Jurassic are similar (Fig.5-e, The type-III oil is representative of the J oil of indicating the oil was derived from the Jurassic coal 2x well Yong-6 (6,035 m). Its characteristics are as follow measures strata. (Fig. 4): (1) Pristane-over-phytane predominance is The type-IV oil represents the Jjs oil of well clear, and the ratio of pristane to phytane ranges from Zheng-l and the J oil of wells Yong-l and Yong-2 2x 2.2 to 2.3; (2) Tricyclic terpanes are in relatively low (6,000 m). Its geochemical characteristics are as abundance, and the relative abundance of C - , C - or follows (Fig. 4): (1) The ratio of pristane to phytane 20 2 1 VolA NoA Oil Source of Reservoirs in the Hinterland of the Junggar Basin 39 ranges from 1.1 to 2.0; (2) The abundance of tricyclic Sha-l. terpanes is high, the relative abundance ofC 21-tricyclic 0.50 terpanes is higher than that of C - or Cwtricyclic • • Well Sha-I, inclusion oils a 0040 terpanes, and the gammacerane index is 0.25 on <> Well Sha-I, free oils I-< • Well Zhuang-I, inclusion oils <> ~ 0.30 average; (3) The abundances of pregnane and DWell Zhuang-I, free oils • Well Zheng-l, inclusion oils ;§' 0.20 homopregnane are relatively high, and the relative o Well Zheng-I, free oils of C C and C steranes abundance , - O.IO+--~~----r--, 2r 2S 29-regular 0_52 0_54 0.56 0.58 0.60 increases in tum; (4) The abundance of ~-carotane is aaaC,,20S/(20S+20R) relatively high. The distribution pattern of C - , C ­ 20 21 and C terpanes ofthe oil is similar to that of Fig. 6 Maturity parameter distribution offree oils 23-tricyclic the rock from the Wuerhe formation. The parameters and inclusion oils values of the biomarker of the type-IV oil are between those of type-Il and type-III (Fig. 5-e, f), indicating that the type-IV oil was generated from source rocks in the Wuerhe formation and Jurassic coal measures 20 80 strata. c\c 4.2 Fluid inclusions and hydrocarbon accumulation .§',§'·xWCII Zheng-I, ;;)!.,S) history o~ 40 Well Zheng-l , eoal(J,b) :.$' 2f Studies on oil-bearing fluid inclusions and the ~ Well Zhcng I, inclusion oils -<:J'U ... compositions of reservoired free oils have been q" 60 Well Zheng-l , free OIls L.I Well Sha-Lfrcc OIls 0 reported (George, et al., 1997; Pan, et al., 2003). Well Zhuang-I, free oils <> According to these studies, the oil-bearing fluid Well Zhuang-l, inclusion OilS·. inclusions, trapped in authigenic minerals of reservoir Well Sha-L, inclusion oils rocks, were believed to be representative of the initial 100 0 oils. However the free oils were mixtures of r--,---.----,---,-----¥ hydrocarbons of different stages. Therefore, the o 20 40 60 80 100 Fluorene, % compositional difference of the reservoired oil from the oil inclusions. reflects its multiple oil source rocks Fig. 7 Distribution of dibenzofuran, fluorene and or maturity variations in different geologic periods. dibenzothiophene of free oils and inclusion oils The biomarker compositions of the inclusion oils and free oils from Jls sandstone reservoir rocks of The biomarker composition of inclusion oil is very wells Zhuang-l, Sha-l and Zheng-I were analyzed similar to that of free oil from well Zheng-l, but the (Fig. 3). The results showed that maturity parameters previous study showed that the free oil (type-IV) is a such as Ts/(Ts+Tm) and aaa -C and 2920S/(20S+20R) mixture of oils from the Wuerhe formation and Jurassic fluorene series distribution of inclusion oil were coals measure. similar to those of free oil in well Zheng-l , but those In addition, from the distribution of the of inclusion oils and free oils in wells Zhuang-l and homogenization temperatures of fluid inclusions it was Sha-l are significantly different (Figs. 6, 7). shown that the temperature distribution of fluid Previous study showed that the free oils in wells inclusions from well Zheng-l is greatly different from Zhuang-l and Sha-I belong to type-I oil, and their that from wells Zhuang-l, Sha-l and Yong-l. The biomarker compositions are similar to source rocks of temperature from well Zheng-I mainly ranges between the Fengcheng formation. But the ratio of pristane to 100°C and 120°C, but the temperature from wells phytane and the content of dibenzofuran in the free Zhuang-l, Sha-l and Yong-l ranges between 80°C and oils are higher than those in the oil inclusions and 100°C (Fig. 8). source rocks of the Fengcheng formation, which are Combined with basin evolution, it is concluded that close to those of the extracts from the Jurassic coals crude oils in wells Sha-l, Zhuang-l and Yong-l (Fig. 7), indicating that the early oil of wells Zhuang-l accumulated mainly from the end of the early and Sha-I originated from the Fengcheng formation, Cretaceous to the late Paleogene. While the mixed oil of and during the late oil-filling process the Jurassic well Zheng-l accumulated mainly since the late coal-measure source rock made contribution to free Paleogene (Fig. 8). oils in the current reservoir of wells Zhuang-l and Petroleum Science 40 2007 500 500 1000 1000 1500 1500 E. ~ 2000 2000 .s .s fr 2500 fr2500 c Cl 3000 3000 K 3500 3500 IS 180 150 120 90 60 30 0 180 120 150 90 60 30 0 Time, Ma Time, Ma (a) (b) Well Zhuang-l E 1800 a 3000 ..c 2400 .s" 80'C-IOO'C 0.. ~ 4000 1OO'C-l20'C IOWC-120'C 180 150 120 90 60 0 30 180 150 120 90 60 30 0 Time, Ma Time, Ma (c) (d) Fig. 8 Thermal history and hydrocarbon accumulation period of Jurassic reservoirs (Modified from Li, et al., 2006) western depression to the well Pen-l have only 4.3 Hydrocarbon generation and expulsion history reached the maturity stage (Fig. 9). On the basis of analyzing the buried history of 4.4 Analysis of oil-source of different stages deposits and the thermal history of hydrocarbon From the oil-source rocks correlation and evolution of individual wells (e. g. well Zheng-l, combined with the analysis of hydrocarbon Sha-l, Zhuang-l), the hydrocarbon generation and expulsion history of the south-north oriented Yad5 accumulation history of the oil reservoirs in the study area, it is concluded that from Cretaceous to section is simulated across the Changji depression and Palaeogene, the crude oils in Kjtg of well Yong-6 the western depression to the well Pen-l (Figs. 2, 9). Through this comprehensive analysis, it is (5,978 m) and Jurassic of well Yong-l (6,118 m) and concluded that the hydrocarbon generation history of well Yong-2 (6,000 m) originated from the Wuerhe the western depression to the well Pen-l is similar to Formation of the Permian in the Changji depression, that of the Permian source rocks in the Changji and Jurassic oils of well Zhuang-l and well Sha-l depression, and since the late Jurassic the Permian were generated from the Fengcheng Formation of the source rocks moved into the gas generation phase. Permian in the western depression to the well Pen-l . However the thermal evolution history of the Jurassic However based on Junggar Basin evolution history, source rocks in both depressions is significantly the Fengcheng Formation and Wuerhe Formation of the Permian came into the gas generation phase, so it different, and at the end of the Palaeogene the Jurassic source rocks in the Changji depression came can be explained by the adjustment of the deep oil into the peak period of hydrocarbon generation, but reservoirs (Fig. I O-a). After the Palaeogene, the Che-Mo palaeohigh was those in the western depression to the well Pen-l just tilted by the Himalayan movement and crude oils in the reached the low maturity stage. Up to now the Jurassic source rocks in the Changji depression have study area were charged from the Changji depression (Fig. I O-b), at the same time Jurassic coal-measure reached the high maturity stage but those in the VolA NoA Oil Source of Reservoirs in the Hinterland ofthe Junggar Basin $----------- ~ 8000 J, "L-_---. ---,- ---,-__--' 0.001 i 50000 100000 150000 100000 150000 Distance, m Distance, m . i : ) 'r,1 ? ':: - ~ I 14000 "L-_---.- ----.,.-- ...,..__--I 'L-_---. ---,- ---,-__--' oj 50000 100000 150000 100000 150000 Distance, Tn Distance. rn 5~ 4: ; 31 ' ;7 11 "" 8000 '" -', 2 _~ I 14000"L-_---. ---,- ---,-__--' 50000 150000 150000 Fig. 9 Thermal evolution history ofthe Yad5 section source rocks in the Changji depression entered into the was generated from the Jurassic coal-measure source peak period of oil generation, and then crude oils rocks, and the type-IV oil was a mixture of oils from the Permian and Jurassic coal measures. produced from Jurassic coal-measure source rocks The tectonic evolution history of the Che-Mo accumulated to form Jurassic reservoirs of well Yong-6 Palaeohigh and hydrocarbon generation history of the (6,035 m), and the crude oil of wells Yong-I(6,118 m), western depression to the well Pen-I and the Changji Yong-2 (6,000 m), Zhuang-I and Sha-l were mixed by Depression controlled the hydrocarbon origin in coal-generated oil. The Jurassic reservoir of well different stages of the reservoirs. Before the Che-Mo Zheng-l was filled by the mixed oil of the Jurassic reservoir in well Yong-I. Palaeohigh was tilted, oils just came from the Permian source rocks in the western depression to the well Pen-I 5. Conclusions and the Changji depression during the Cretaceous­ The crude oils in the study area can be classified Paleogene period. And since the end of the Paleogene, into four types: the type-I oil was derived from Pjf oils were mainly derived from the Jurassic source rocks (Permian Fengcheng formation), the type-Il oil was in the Changji depression because the Palaeohigh generated from P (Wuerhe formation), the type-III oil 2w plunged in the south and was elevated in the north. Petroleum Science 42 2007 Well Zhuang-I K-E Well Zheng-I Well Yong-I WellYong-6 Well Yong-2 Oils from the P,w in Changji depression (a) After Palaeogene Che-mo Palaeohigh was tilted Pr/Ph=1.33, Type-Iv GJ~O,2, aaa20RC,lCQ~O, 18 abundance' of li--earrotane is high Pr/Ph=0.80, Type-II GI~0.60, aaa20RC,Ic",~0.38 abundance or'p-earrotane is very high • Type-Iv Pr/Ph~ 1.8, (rl=O.20, PriPh= 1.29, Type, I aaa20RC ,.IC .,=0.10 GI=O.3, abundance'ofp-carrotanc is low aaa20RC .•!C .,=0.25, abundance'of p-earrotane is very high Pr/Ph> 1.42. Type-I\' GI=024-0.41, aaa20RC,,!C,,=0.18. abundance of j)-earrolane is high Pr/Ph > 2, Type-Ill GI~O.03, abundance ofaaa20RC", C" --«>- Oils from the adjustment of the reservoirs and p-earrotane isvery low - Oils from the Jurassic coals (b) G I: gamrnacerane/Cj, hopane Fig. 10 Accumulation patterns of reservoirs in study area in different periods Chinese) Meantime, the crude oils in the existing hydrocarbon reservoirs began to migrate in the updip direction. He D. F., Zhai G. M., Kuang J., et at. (2005) Distribution and tectonic features of paleo-uplifts in Junggar basin. Chinese J. Acknowledgements Geol. Sci., 40(2), 248-261 (in Chinese) The authors benefited from the constructive Li w., Zhang Z. H., Mei L., et al. (2006) Geochemical features of comments on hydrocarbon generation history from Prof. petroleum accumulation of Jurassic reservoirs in hinterland, Qiu Nansheng of China University of Petroleum, of the Junggar basin. Chinese J. Geol. Sci., 41(4), 663-675 (in Beijing, whose help is much appreciated. Chinese) Luo 1. H., Che Z. C. and Li J. L. (2000) Structural features of the References Jurassic basins in West China and Middle Asia. Chinese J. George S. C., Krieger F. w., Eadington P. 1., et al. (1997) Geol. Sci., 35(4), 404-413 (in Chinese) Geochemical comparison of oil-bearing fluid inclusions and Pan C. C., Yang J. Q., Fu 1. M., et al. (2003) Molecular produced oil from the Toro sandstone, Papua New Guinea. correlation of free oil and inclusion oil of reservoir rocks in Organic Geochemistry, 26(3/4), 155-173 the Junggar basin, China. Organic Geochemistry, 34, 357-374 Guo C. Q., Shen Z. M., Zhang L. Y, et al. (2005) Biogenic origin Wang X. L. and Kang S. F. (1999) Analysis of crude origin in characteristics of hydrocarbon source rocks and classification hinterland and slope of Northwest margin, Junggar basin. of oils in the south part of Junggar basin, China. Journal of Xinjiang Journal of Petroleum Geology, 20(2), 108-112 (in Chengdu University of Technology, 32(3), 257-262 (in Chinese) Oil Source of Reservoirs in the Hinterland ofthe Junggar Basin VolA No.4 43 Wang Y. T. and Jiang S. B. (1995) Hydrocarbon-generating About the first author characteristics of the Jurassic and its exploration. Xinjiang Li Wei was born in 1979 and Journal of Petroleum Geology, 16(3), 222-225 (in received his PhD in petroleum Chinese) geology from China University of Wang Y. T., and Lan W. F. (1994) Origin of hydrocarbons and its Beijing in 2006. Now he is a exploration in Cainan oilfield. Xinjiang Journal of Petroleum geologist with Sinopec International Geology, 15(1),30-36 (in Chinese) Petroleum Exploration and Wu G. Y. and Ma L. (2003) Orogeny and coupled/decoupled Production Corporation with his basin developing: Application in petroliferous basin analyses. . research interests in geochemistry Petroleum Experimental Geology, 25(6), 648-660 (in and reservoir geology. E-mail: echolw@163.com Chinese) Zou H. Y., Hao F. and Zhang B. Q., et al. (2005) History of (Received October, 9, 2006) hydrocarbon-filling and remigrating in hinterland of the (Edited by Zhu Xiuqin) Junggar basin. Chinese J. Geol. Sci., 40(4), 499-509 (in Chinese) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Petroleum Science Springer Journals

Oil source of reservoirs in the hinterland of the Junggar basin

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Springer Journals
Copyright
Copyright © 2007 by China University of Petroleum
Subject
Earth Sciences; Mineral Resources; Industrial Chemistry/Chemical Engineering; Industrial and Production Engineering; Energy Economics
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1672-5107
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1995-8226
DOI
10.1007/BF03187453
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Abstract

Petroleum Science 2007 VolA NoA Li Wei Zhang Zhihuan", Yang Yongcai' and Meng Xianlong' ,2, (1. International Petroleum Exploration and Production Company, Sinopec, Beijing 100083, China) (2. Key Laboratory ofHydrocarbon Accumulation, Ministry ofEducation, China University ofPetroleum, Beijing 102249, China) (3. West China Branch ofInstititute ofExploration and Development, Sinopec, Urumqi, Xinjiang 830011, China) Abstract: Through oil-oil and oil-source correlation and combined with the comprehensive study of hydrocarbon generation and accumulation history, the oil sources of typical reservoirs of different geologic periods in the hinterland of the Junggar basin are revealed. It is concluded that the crude oils in the study area can be classified into four types: The oil in the area of well Zhuang-l and well Sha-l belongs to type-I, which was generated from Cretaceous to Paleogene (K-E) and its source rocks are distributed in the Fengcheng formation of the Permian in the western depression to the well Pen-I. The oil in the area of well Yong-6 (Kltg) belongs to type-II, which was generated from Cretaceous to Paleogene and its source rocks are distributed in the Wuerhe formation of the Permian in the Changji depression. The oil in the area of well Yong-6 (J2x) belongs to type-III, which was generated at the end of the Paleogene and its source rocks are distributed in the coal measures of the Jurassic in the Changji depression. The oil of well Zheng-l and well Yong-l belongs to type-IV, which was generated in the Paleogene, and its source rocks are distributed in the Wuerhe formation of the Lower Permian and coal measures of the Jurassic. It is indicated that the hydrocarbon accumulation history in the study area was controlled by the tectonic evolution history of the Che-Mo palaeohigh and the hydrocarbon generation history of well Pen-l in the western depression and Changji depression. Key words: Oil source correlation, hydrocarbon accumulation history, Che-Mo palaeohigh, Junggar basin 1. Introduction 2. Geological background In recent years, many new oil fields have been The Junggar basin is located in the northern part of discovered in the hinterland of the Junggar basin, Xinjiang Uygur Autonomous Region, China, in an area showing great oil-prospecting potential. Previous of about 1.3 X 10 km'. The Junggar basin is a large set studies revealed that the Permian formations are the of superposed basins of different characteristics, which most important oil source rocks in the hinterland of the were developed in the late Palaeozoic, Mesozoic and basin (Wang and Kang, 1999). Moreover the Jurassic Cenozoic, and located at the junction of the Siberia, coal measures strata in the hinterland of the basin had Tarim and Kazakhstan blocks. It was developed on the excellent potential as hydrocarbon source rocks (Wang Junggar terrain, consisting of Precambrian crystalline and Jiang, 1995), and the crude oils of the Qigu oil field basement in the upper part and slightly metamorphic in the south Junggar basin and the crude oils of the Palaeozoic basement in the lower part. Cainan oil field in the east Junggar basin have been During the Permian, in the stage of foreland basin, proved to be derived from the source rocks in the the western depression to the well Pen-l and Changji Jurassic (Wang and Lan, 1994; Guo, et al., 2005). depression were developed, which was an important The study area is located in the desert, the hinterland period of source rock formation (Luo, et al., 2000; Wu of the Junggar basin. Previous work showed that the and Ma, 2003). At the end of Xishanyao formation complexity of tectonic evolution in this area led to deposition in the Middle Jurassic, the Junggar basin reservoir formation from multi-sources in multi-phases evolved to a compresso-shearing structure environment (Zou, et al., 2005). So it is difficult to correctly identify and a giant northeast-southwest oriented Che-Mo oil source rocks only through oil-source correlation. By palaeohigh (from Chepaizi uplift to Mobei uplift) was using various geochemistry analysis techniques for formed in the hinterland of the basin. The Che-Mo reservoirs and combined with the study on hydrocarbon palaeohigh still kept the east-west oriented anticline generation history of source rocks, this paper shape in the Cretaceous. However it was tilted by the investigates the main oil sources of typical reservoirs of Himalayan movement (Fig. I) and the palaeohigh different geologic periods in the study area and disappeared and the present large slope was formed (He, discusses whether or not the Jurassic coal measures et al., 2005). strata contributed to the reservoirs. The study area, including Block I and Ill, is located VolA NoA Oil Source of Reservoirs in the Hinterland of the Junggar Basin N----------. S Well Zheng-I Well Zhuang-l Well Zheng-l Well Zhuang-l 0 +-------==------I---......,j.,=---~ K,tg o J,x J,x r-- -t-- J,s ~ 500 if 500 r-- ir J,b '" (b) (a) Well Zhe~g-I Well Zhuang-I WellZheng-1 WellZhuang-1 N,s +-------+----+----1 K,d K,d if if 0- 0- 2000 1500 K,tg a '" a '" J,x J,s J,b (e) (d) Well Zheng-I Well Zhuang-I Well Zheng-I Well Zhuang-I N,s 1000 2000 K,d if 0- t 3000 a '" '" Kitg J,x 4000 J,s J,b (f) (el Fig. I Tectonic evolution history of Che-Mo palaeohigh in the central depression region in the hinterland of the 3. Samples and analysis methods Junggar basin. The main body of the study area is Samples, including crude oils, sandstones, located in a large slope from the western part of the mudstones and coals, were collected from J 1S Changji depression to the western depression to the (Sangonghe formation in the Jurassic) in well Zhuang-l, west of well Pen-l (Fig. 2) and bounded by the well Sha-I and well Zheng-I of central block I, and J 2x Dabasong uplift in the north and by the piedmont (Xishanyao formations in the Jurassic) and Kjtg fault-bench belt on the south margin of the Junggar (Toutunhe Formation in the Cretaceous) in wells Yong-I, basin in the south. The Jurassic and Cretaceous are the Yong-2 and Yong-6 (Fig. 3). main prospecting targets in the study area. Petroleum Science 36 2007 G Well IS:] Boundary line of Junggar basin ~ Fault [j£] Study area Q Boundary line ofteetonic units [[] Yad5 section o 20 40 60(km) I I ~. ~. " .. --_. __ .__ .__ . __ ._-'............. ~~. Sikeshu depression " ~ t--t--,J-"r-::...,Yon -! . - .~ - . _ r'->'~---i+--"" o·ng:.ft·- CD Western depresion to Well Pen-I ® Changji depression Piedmont fault-bench belt ® Dabasong uplift ® Zhongguai uplift Qigu oil field @ Maqiao uplift ® Mobei uplift • Fig. 2 Tectonic units and well locations in study area Well Yong-l D~l;tit Lithostrata K,tg K,tg K,tg ~= • J,x 5960B 600~1BJ J,x J,x 6040t:= liS EB Fine sand Ea Silty sand ~ Shaly sand~ Mudstone _ Coal • Sample Fig. 3 Generalized stratigraphy of the Jurassic and Cretaceous reservoirs and sampling sites Rock samples were powdered and sieved through a oven was initially set at 80°C for 1 min, then sieve (60 mesh) and then were extracted in a Soxhlet programmed to 250°C at 3.5 °C/min and to 300°C at 2 apparatus with methylene chloride for 24 hours. The °C/min, finally it was held for 15 min. extract and crude oil were fractionated on a neutral Fluid inclusions were observed with a Leica DMRXP microscope and the oil-bearing inclusions alumina chromatographic column into saturates, were distinguished by UV fluorescence. The aromatics and a polar fraction, by sequential elution with n-hexane, toluene and chloroform. Gas homogenization temperatures of aqueous inclusions chromatograph-mass spectrometer (GC-MS) analysis of were measured on a Linkam 3500 heater. We followed the techniques of Pan, et al. (2003) to prepare the saturates and aromatics fractions were carried out on a Thermo-Finnigan Trace-DSQ GC-MS Detector. The GC samples and to analyze the compositions of their oil VolA NoA Oil Source of Reservoirs in the Hinterland of the Junggar Basin 37 pristane to phytane (PrlPh) is in a range from 1.0 to 1.5; inclusions. (2) Tricyclic terpanes are in relatively high abundance, 4. Results and discussion the relative abundance of C C or C -tricyclic 20-, 21-, 23 terpanes increases in tum, and the gammacerane index 4.1 Oil-oil and oil-source correlation (gammacerane/Co-hopane) and Ts/(Ts+Tm) are 0.30 According to the distribution and composition of biomarkers, crude oils in the study area can be classified and 0.32 respectively on average; (3) The abundance of into four types. pregnane and homopregnane is relatively high, the The type-I oil is mainly from Jrs in well Zhuang-l relative abundance of C - , C or C regular steranes 27 28-, 29- and well Sha-l. The compositional characteristics of also increases in tum; (4) The abundance of p-carotane bio-marker are as follows (Fig. 4): (1) The ratio of is very high. m/z:191 m/z:217 m/z: 125 m/z:85 , oH C C 'IIIIIII.IIIJ I H R - earrotane II1II I I c 23 JrlL~,elll Sha-I (J, ) Tm P Ts G I Hp ~l~ J _ ~~.~~v·'· :ti B -ea rotane Type-l Type-II Type-Ill Type-IV 11111111·111 ~~ot_an.Leill<l1WIol»l;J.lJ.J..LLLLLJ..UJ...J....c.. Fig.4 Mass chromatograms of oils from J J and k.tg reservoirs in study area 1s, 2x • C20-C tricyclic terpanes; C30R C30-hopane; P: pregnane; HP: homopregnane; G: gammacerane 23• The oil from Kjtg of well Yong-6 belongs to The type-I oil and source rock from the Fengcheng type- II. The compositional characteristics of biomarker formation of the Permian (Pjf) have similar distribution are as follows (Fig. 4): (1) The ratio of pristane to patterns of biomarkers as indicated by the significant phytane ranges from 0.7 to 0.9; (2) Tricyclic terpanes overlapping on the plots of homohopane are in relatively high abundance, and the relative index-C35/(C31+C32+C33+C34+C35) and C 201C21-tricyclic abundance of C terpanes is higher than that terpane, gammacerane index and C 23/C21-tricyclic 2l-tricyclic of C or C terpanes, and the gammacerane terpane ratio (Fig.5-a, b). However the ratio of pristane 20- 23-tricyclic index (gammacerane/Cjs-hopane) and Ts/(Ts+Tm) are to phytane of the Permian source rocks extracts is 0.8 respectively 0.65 and 0.51 on average; (3) The on average, lower than that of the oil. Petroleum Science 38 2007 0.14 + Prf mudstone 0.6 + P,f mudstone • Piw mudstone • Piw mudstone EJ '" 0.12 '" Oils in Well Sha-l (J,s) '" Oils in Well Sha-l(J,s) + .g 0.5 o Oils in Well Zheng-l(J,s) o Oils in Well Zheng-I(J,s) ] 0.10 <> Oils in Well Zhuang-I(J,s) .~ 0.4 <> Oils in Well Zhuang-l(J,s) s: '" + ~ 0.08 ~ 0.3 .8 "" 0.06 I. ~D I / ~ 0.2 ~ 0.04 '" o 0.1 :r: 0.02 0.00 -t--....,---,--r--,...---,----, 0.0 -r----.,....----,.------,-----, 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0.0 0.5 1.0 1.5 2.0 C,jC,,-tricyclic terpane C,/C" -tricyclic terpane (a) (b) 0.14 1.0 + Oils in Well Yong-6(k,tg) :. 0.12 • J coal ~ 0.8 • Prw mudstone '" ] 0.10 '·· - Pif mudstone ~ t;; 0.6 g 0.08 •• a ], + Oils in Well Yong-oik.tg) .2 0.06 + Oils in Well Yong-6(6035m) ~~ 0.4 x Oils in Well Yong-2(5056m) \. +' +. ·1 § 0.04 u • J coal J 0.2 :r: 0.02 • Psw mudstone • • ·1 - Pif mudstone 0.00 -t--......--r----.-----,--,.---, 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0.2 OJ 0.4 0.5 0.6 0.7 C"fC,,-regular sterane C"fC sterane 29-regular (c) (d) 1.2 4.5 + Oils in Well Yong-6(k,tg) '" Oils in Well Yong-lt.l.x) + Oils in Well Yong-6(k,tg) 4.0 o Oils in Well Yong-2(6000n1) o Oils in Well Yong-2(600Om) <> Oils in Well Yong-I(J,s) 1.0 + Oils in Well Yong-6(6035m) - J coal '" Oils in Well Yong-It.I.x) 3.5 +x o Oils in Well Yong-I(J,s) x Oils in Well Yong-2(5056m) 3.0 ? 0.8 Third + Oils in Well Yong-6(6035m) ~ 2.5 x Oils in Well Yong-2(5056m) aD Fouth '" J 0.6 • Second 2.0 + - J coal o '" } 0.4 1.5 1.0 0.2 0.5 0.0 -r---..---,---,---,-----, 0.0 -r---..---..---..---.,....------, 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Gammacerane/Cj.- hopane Gammacerane/Cj.- hopane (e) (\) Fig.5 Distribution of biomarker composition of four types oil *C f(C + C26): C C terpane) 24 24 24-tetracyclicf(C 24-tetracyclic+ 26-tricyclic abundances of pregnane and homopregnane are C terpanes decreases III tum, with 23-tricyclic relatively high, the relative content of C - , C - or gammacerane index being 0.03 on average; (3) The 27 2S C steranes also increases in tum, and the relative abundance of pregnane and homopregnane is 29-regular abundance of C steranes is relatively high; (4) relatively low, and C steranes is predominance, 27-regUlar 29-regular The abundance of B-carotane is very high. but the abundances of C - and C - regular steranes are 27 28 The biomarker composition of the type-II oil is very low; (4) It does not contains B-carotane. The similar to the source rock from the Wuerhe formation of biomarker composition of type-III oil shows typical the Permian (P and it can be seen from the characteristics of coal-generated oils. GC-MS analysis 2w), distribution pattern of C - , C - and C tricyclic showed that the geochemical characteristics of the oil 20 2 1 23 terpanes and the pattern of C - , C - and C biomarker and of hydrocarbon source rock from coal 27 2S 29-regular steranes (Fig.5-c, d). f), measure strata in the Jurassic are similar (Fig.5-e, The type-III oil is representative of the J oil of indicating the oil was derived from the Jurassic coal 2x well Yong-6 (6,035 m). Its characteristics are as follow measures strata. (Fig. 4): (1) Pristane-over-phytane predominance is The type-IV oil represents the Jjs oil of well clear, and the ratio of pristane to phytane ranges from Zheng-l and the J oil of wells Yong-l and Yong-2 2x 2.2 to 2.3; (2) Tricyclic terpanes are in relatively low (6,000 m). Its geochemical characteristics are as abundance, and the relative abundance of C - , C - or follows (Fig. 4): (1) The ratio of pristane to phytane 20 2 1 VolA NoA Oil Source of Reservoirs in the Hinterland of the Junggar Basin 39 ranges from 1.1 to 2.0; (2) The abundance of tricyclic Sha-l. terpanes is high, the relative abundance ofC 21-tricyclic 0.50 terpanes is higher than that of C - or Cwtricyclic • • Well Sha-I, inclusion oils a 0040 terpanes, and the gammacerane index is 0.25 on <> Well Sha-I, free oils I-< • Well Zhuang-I, inclusion oils <> ~ 0.30 average; (3) The abundances of pregnane and DWell Zhuang-I, free oils • Well Zheng-l, inclusion oils ;§' 0.20 homopregnane are relatively high, and the relative o Well Zheng-I, free oils of C C and C steranes abundance , - O.IO+--~~----r--, 2r 2S 29-regular 0_52 0_54 0.56 0.58 0.60 increases in tum; (4) The abundance of ~-carotane is aaaC,,20S/(20S+20R) relatively high. The distribution pattern of C - , C ­ 20 21 and C terpanes ofthe oil is similar to that of Fig. 6 Maturity parameter distribution offree oils 23-tricyclic the rock from the Wuerhe formation. The parameters and inclusion oils values of the biomarker of the type-IV oil are between those of type-Il and type-III (Fig. 5-e, f), indicating that the type-IV oil was generated from source rocks in the Wuerhe formation and Jurassic coal measures 20 80 strata. c\c 4.2 Fluid inclusions and hydrocarbon accumulation .§',§'·xWCII Zheng-I, ;;)!.,S) history o~ 40 Well Zheng-l , eoal(J,b) :.$' 2f Studies on oil-bearing fluid inclusions and the ~ Well Zhcng I, inclusion oils -<:J'U ... compositions of reservoired free oils have been q" 60 Well Zheng-l , free OIls L.I Well Sha-Lfrcc OIls 0 reported (George, et al., 1997; Pan, et al., 2003). Well Zhuang-I, free oils <> According to these studies, the oil-bearing fluid Well Zhuang-l, inclusion OilS·. inclusions, trapped in authigenic minerals of reservoir Well Sha-L, inclusion oils rocks, were believed to be representative of the initial 100 0 oils. However the free oils were mixtures of r--,---.----,---,-----¥ hydrocarbons of different stages. Therefore, the o 20 40 60 80 100 Fluorene, % compositional difference of the reservoired oil from the oil inclusions. reflects its multiple oil source rocks Fig. 7 Distribution of dibenzofuran, fluorene and or maturity variations in different geologic periods. dibenzothiophene of free oils and inclusion oils The biomarker compositions of the inclusion oils and free oils from Jls sandstone reservoir rocks of The biomarker composition of inclusion oil is very wells Zhuang-l, Sha-l and Zheng-I were analyzed similar to that of free oil from well Zheng-l, but the (Fig. 3). The results showed that maturity parameters previous study showed that the free oil (type-IV) is a such as Ts/(Ts+Tm) and aaa -C and 2920S/(20S+20R) mixture of oils from the Wuerhe formation and Jurassic fluorene series distribution of inclusion oil were coals measure. similar to those of free oil in well Zheng-l , but those In addition, from the distribution of the of inclusion oils and free oils in wells Zhuang-l and homogenization temperatures of fluid inclusions it was Sha-l are significantly different (Figs. 6, 7). shown that the temperature distribution of fluid Previous study showed that the free oils in wells inclusions from well Zheng-l is greatly different from Zhuang-l and Sha-I belong to type-I oil, and their that from wells Zhuang-l, Sha-l and Yong-l. The biomarker compositions are similar to source rocks of temperature from well Zheng-I mainly ranges between the Fengcheng formation. But the ratio of pristane to 100°C and 120°C, but the temperature from wells phytane and the content of dibenzofuran in the free Zhuang-l, Sha-l and Yong-l ranges between 80°C and oils are higher than those in the oil inclusions and 100°C (Fig. 8). source rocks of the Fengcheng formation, which are Combined with basin evolution, it is concluded that close to those of the extracts from the Jurassic coals crude oils in wells Sha-l, Zhuang-l and Yong-l (Fig. 7), indicating that the early oil of wells Zhuang-l accumulated mainly from the end of the early and Sha-I originated from the Fengcheng formation, Cretaceous to the late Paleogene. While the mixed oil of and during the late oil-filling process the Jurassic well Zheng-l accumulated mainly since the late coal-measure source rock made contribution to free Paleogene (Fig. 8). oils in the current reservoir of wells Zhuang-l and Petroleum Science 40 2007 500 500 1000 1000 1500 1500 E. ~ 2000 2000 .s .s fr 2500 fr2500 c Cl 3000 3000 K 3500 3500 IS 180 150 120 90 60 30 0 180 120 150 90 60 30 0 Time, Ma Time, Ma (a) (b) Well Zhuang-l E 1800 a 3000 ..c 2400 .s" 80'C-IOO'C 0.. ~ 4000 1OO'C-l20'C IOWC-120'C 180 150 120 90 60 0 30 180 150 120 90 60 30 0 Time, Ma Time, Ma (c) (d) Fig. 8 Thermal history and hydrocarbon accumulation period of Jurassic reservoirs (Modified from Li, et al., 2006) western depression to the well Pen-l have only 4.3 Hydrocarbon generation and expulsion history reached the maturity stage (Fig. 9). On the basis of analyzing the buried history of 4.4 Analysis of oil-source of different stages deposits and the thermal history of hydrocarbon From the oil-source rocks correlation and evolution of individual wells (e. g. well Zheng-l, combined with the analysis of hydrocarbon Sha-l, Zhuang-l), the hydrocarbon generation and expulsion history of the south-north oriented Yad5 accumulation history of the oil reservoirs in the study area, it is concluded that from Cretaceous to section is simulated across the Changji depression and Palaeogene, the crude oils in Kjtg of well Yong-6 the western depression to the well Pen-l (Figs. 2, 9). Through this comprehensive analysis, it is (5,978 m) and Jurassic of well Yong-l (6,118 m) and concluded that the hydrocarbon generation history of well Yong-2 (6,000 m) originated from the Wuerhe the western depression to the well Pen-l is similar to Formation of the Permian in the Changji depression, that of the Permian source rocks in the Changji and Jurassic oils of well Zhuang-l and well Sha-l depression, and since the late Jurassic the Permian were generated from the Fengcheng Formation of the source rocks moved into the gas generation phase. Permian in the western depression to the well Pen-l . However the thermal evolution history of the Jurassic However based on Junggar Basin evolution history, source rocks in both depressions is significantly the Fengcheng Formation and Wuerhe Formation of the Permian came into the gas generation phase, so it different, and at the end of the Palaeogene the Jurassic source rocks in the Changji depression came can be explained by the adjustment of the deep oil into the peak period of hydrocarbon generation, but reservoirs (Fig. I O-a). After the Palaeogene, the Che-Mo palaeohigh was those in the western depression to the well Pen-l just tilted by the Himalayan movement and crude oils in the reached the low maturity stage. Up to now the Jurassic source rocks in the Changji depression have study area were charged from the Changji depression (Fig. I O-b), at the same time Jurassic coal-measure reached the high maturity stage but those in the VolA NoA Oil Source of Reservoirs in the Hinterland ofthe Junggar Basin $----------- ~ 8000 J, "L-_---. ---,- ---,-__--' 0.001 i 50000 100000 150000 100000 150000 Distance, m Distance, m . i : ) 'r,1 ? ':: - ~ I 14000 "L-_---.- ----.,.-- ...,..__--I 'L-_---. ---,- ---,-__--' oj 50000 100000 150000 100000 150000 Distance, Tn Distance. rn 5~ 4: ; 31 ' ;7 11 "" 8000 '" -', 2 _~ I 14000"L-_---. ---,- ---,-__--' 50000 150000 150000 Fig. 9 Thermal evolution history ofthe Yad5 section source rocks in the Changji depression entered into the was generated from the Jurassic coal-measure source peak period of oil generation, and then crude oils rocks, and the type-IV oil was a mixture of oils from the Permian and Jurassic coal measures. produced from Jurassic coal-measure source rocks The tectonic evolution history of the Che-Mo accumulated to form Jurassic reservoirs of well Yong-6 Palaeohigh and hydrocarbon generation history of the (6,035 m), and the crude oil of wells Yong-I(6,118 m), western depression to the well Pen-I and the Changji Yong-2 (6,000 m), Zhuang-I and Sha-l were mixed by Depression controlled the hydrocarbon origin in coal-generated oil. The Jurassic reservoir of well different stages of the reservoirs. Before the Che-Mo Zheng-l was filled by the mixed oil of the Jurassic reservoir in well Yong-I. Palaeohigh was tilted, oils just came from the Permian source rocks in the western depression to the well Pen-I 5. Conclusions and the Changji depression during the Cretaceous­ The crude oils in the study area can be classified Paleogene period. And since the end of the Paleogene, into four types: the type-I oil was derived from Pjf oils were mainly derived from the Jurassic source rocks (Permian Fengcheng formation), the type-Il oil was in the Changji depression because the Palaeohigh generated from P (Wuerhe formation), the type-III oil 2w plunged in the south and was elevated in the north. Petroleum Science 42 2007 Well Zhuang-I K-E Well Zheng-I Well Yong-I WellYong-6 Well Yong-2 Oils from the P,w in Changji depression (a) After Palaeogene Che-mo Palaeohigh was tilted Pr/Ph=1.33, Type-Iv GJ~O,2, aaa20RC,lCQ~O, 18 abundance' of li--earrotane is high Pr/Ph=0.80, Type-II GI~0.60, aaa20RC,Ic",~0.38 abundance or'p-earrotane is very high • Type-Iv Pr/Ph~ 1.8, (rl=O.20, PriPh= 1.29, Type, I aaa20RC ,.IC .,=0.10 GI=O.3, abundance'ofp-carrotanc is low aaa20RC .•!C .,=0.25, abundance'of p-earrotane is very high Pr/Ph> 1.42. Type-I\' GI=024-0.41, aaa20RC,,!C,,=0.18. abundance of j)-earrolane is high Pr/Ph > 2, Type-Ill GI~O.03, abundance ofaaa20RC", C" --«>- Oils from the adjustment of the reservoirs and p-earrotane isvery low - Oils from the Jurassic coals (b) G I: gamrnacerane/Cj, hopane Fig. 10 Accumulation patterns of reservoirs in study area in different periods Chinese) Meantime, the crude oils in the existing hydrocarbon reservoirs began to migrate in the updip direction. He D. F., Zhai G. M., Kuang J., et at. (2005) Distribution and tectonic features of paleo-uplifts in Junggar basin. Chinese J. Acknowledgements Geol. Sci., 40(2), 248-261 (in Chinese) The authors benefited from the constructive Li w., Zhang Z. H., Mei L., et al. (2006) Geochemical features of comments on hydrocarbon generation history from Prof. petroleum accumulation of Jurassic reservoirs in hinterland, Qiu Nansheng of China University of Petroleum, of the Junggar basin. Chinese J. Geol. Sci., 41(4), 663-675 (in Beijing, whose help is much appreciated. Chinese) Luo 1. H., Che Z. C. and Li J. L. (2000) Structural features of the References Jurassic basins in West China and Middle Asia. Chinese J. George S. C., Krieger F. w., Eadington P. 1., et al. (1997) Geol. Sci., 35(4), 404-413 (in Chinese) Geochemical comparison of oil-bearing fluid inclusions and Pan C. C., Yang J. Q., Fu 1. M., et al. (2003) Molecular produced oil from the Toro sandstone, Papua New Guinea. correlation of free oil and inclusion oil of reservoir rocks in Organic Geochemistry, 26(3/4), 155-173 the Junggar basin, China. Organic Geochemistry, 34, 357-374 Guo C. Q., Shen Z. M., Zhang L. Y, et al. (2005) Biogenic origin Wang X. L. and Kang S. F. (1999) Analysis of crude origin in characteristics of hydrocarbon source rocks and classification hinterland and slope of Northwest margin, Junggar basin. of oils in the south part of Junggar basin, China. Journal of Xinjiang Journal of Petroleum Geology, 20(2), 108-112 (in Chengdu University of Technology, 32(3), 257-262 (in Chinese) Oil Source of Reservoirs in the Hinterland ofthe Junggar Basin VolA No.4 43 Wang Y. T. and Jiang S. B. (1995) Hydrocarbon-generating About the first author characteristics of the Jurassic and its exploration. Xinjiang Li Wei was born in 1979 and Journal of Petroleum Geology, 16(3), 222-225 (in received his PhD in petroleum Chinese) geology from China University of Wang Y. T., and Lan W. F. (1994) Origin of hydrocarbons and its Beijing in 2006. Now he is a exploration in Cainan oilfield. Xinjiang Journal of Petroleum geologist with Sinopec International Geology, 15(1),30-36 (in Chinese) Petroleum Exploration and Wu G. Y. and Ma L. (2003) Orogeny and coupled/decoupled Production Corporation with his basin developing: Application in petroliferous basin analyses. . research interests in geochemistry Petroleum Experimental Geology, 25(6), 648-660 (in and reservoir geology. E-mail: echolw@163.com Chinese) Zou H. Y., Hao F. and Zhang B. Q., et al. (2005) History of (Received October, 9, 2006) hydrocarbon-filling and remigrating in hinterland of the (Edited by Zhu Xiuqin) Junggar basin. Chinese J. Geol. Sci., 40(4), 499-509 (in Chinese)

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Petroleum Science – Springer Journals

Published: Jun 16, 2010

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