(1) Mesoproterozoic strategic location
* * * Three favorable areas are selected, namely Dangba sag belt, Jingxi area and central and northern Hebei area (Figure 6- 1-3). According to the types of superimposed units, hydrocarbon generation conditions and preservation conditions, the Dangba sag is evaluated as the first-class area, and the north-central Hebei and Jingxi sag are the second-class areas (Table 6- 1-5).
1. Dangba sag belt
Dangba sag belt in northern Hebei mainly includes Kuancheng fault depression, Shouwangfen fault depression, Xinchengzi fault depression and Pingquan Gaozhangzi fault depression, which are separated by bulges, with a total area of 3000km2, and its fault depression area is 1052km2 (Figure 6- 1-4).
Figure 6- 1-3 Evaluation Map of Mesoproterozoic and Neoproterozoic Oil-bearing Favorable Areas in Beijing-Hebei Region
Table 6- 1-5 Basic parameters and evaluation table of Mesoproterozoic block
Figure 6- 1-4 Comprehensive Achievement Map of Hebei Depression in Yanshan Area
(1) survey of exploration
9 1 oil seedlings have been found in Cambrian-Ordovician and Mesoproterozoic in the northern Hebei depression, which are distributed in Lingyuan, Pingquan, Kuancheng, Chengde and Xinglong counties in the plane, and involve the Five Series 10 group in the vertical direction. The distribution law of plane and longitudinal direction is very obvious.
Planarly, oil seedlings are mainly concentrated in Dangba depression zone, and 69 of 9 1 oil seedlings are distributed in Dangba depression zone, accounting for 75.8% of the total oil seedlings. In Dangba depression zone, oil seedlings are concentrated in huapi anticline and double-hole anticline zone, and there are 59 oil seedlings in both anticlines, accounting for 64.8% of the total oil seedlings and 85.5% of Dangba depression zone. It shows that anticline is the place where oil seedlings are enriched.
In the vertical direction, oil seedlings are concentrated in the Mesoproterozoic Jixian series, with 69 oil seedlings, accounting for 82.4% of the total oil seedlings. Mainly concentrated in 3 groups (lines), including 55 Tieling groups, accounting for 60.4% of the total number of oil seedlings; Wumishan Formation 13, accounting for14.3%; Lower CAMBRIAN 12, accounting for 13.2%. Oil seedlings are concentrated in the upper part of the oil-producing area. Of the 55 oil seedling spots in Tieling Formation, 42 are distributed in the second member (upper part) of Tieling Formation. Wumishan Formation has 13 oil seedling points and 12 oil seedling points in the upper part.
The anticlinal structural belts such as Shuangdong, Huapi, Zhangjiataizi and Puhe were discovered, in which the Mishan Formation was exposed in the Shuangdong anticlinal belt, which destroyed the Shuangdong ancient oil reservoir. The high point of crustal structure in Kuancheng fault depression exposed Tieling Formation, and the reservoir was also damaged to some extent. In addition, other areas of the fault depression zone were covered by Jurassic and well preserved in Mesoproterozoic. However, the underground geological structure in the Jurassic volcanic rock covered area is not clear except for the anticline structures such as double caves, huapi and Zhangjiataizi which have been found in the depression. The exploration degree in this area is low, and only a seismic test profile with a length of 18km was made in Kuancheng. Combined with electrical prospecting, Puhe anticline was discovered, which needs to be further implemented.
(2) Source-reservoir-cap assemblage
Source rocks: mainly shale of Hongshuizhuang Formation and Xiamaling Formation and carbonate rocks of Wumishan Formation. The organic carbon content of Xiamaling Formation shale is high in Shuangdong anticline and Daying Township to the west of Chengde County, and the total organic carbon content is more than 2.0%. The huapi anticline zone is a low value area, and the total organic carbon is 0.5 1% ~ 0.89%. The rest of the Dangba syncline is 1.0% ~ 2.0%. Seen from the whole area, most areas are good source rocks. There are also two high-value areas of organic carbon content in the shale of Hongshuizhuang Formation, and the total organic carbon content in Kuancheng Huapi anticline and its surrounding areas is the highest, with an average of about 4%. Shuangdong anticline is the second highest value area, and the total organic carbon content is more than 3.0%. In Dangba syncline, the total organic carbon content is more than 2.0%. The thermal evolution of source rocks is influenced by volcanic rocks, and the evolution is uneven. The Rb of Hongshuizhuang Formation is between 0.63% and 2.66%, with an average of 65438 0.07%. About 85% samples with Rb less than 1.30% are in the oil generation stage. The samples near igneous rocks in lingyuan city and Chengde County have reached the dry gas stage. The hydrocarbon generation intensity of Mesoproterozoic is (500 ~ 600) × 104t/km2.
Reservoir-cap assemblage: Mesoproterozoic in this area is well preserved. The argillaceous rocks of Xiamaling Formation and Hongshuizhuang Formation are the best caprocks in northern North China. The argillaceous rock is mainly dark shale, and its permeability is generally less than 10-9μm2, so it has good impermeability. There are three complete sets of reservoir-cap assemblages, namely Wumishan Formation reservoir-Hongshuizhuang Formation source cap, Tieling Formation source cap-Xiamaling Formation source cap and Ordovician reservoir-Carboniferous source cap.
(3) Reservoir-forming characteristics
Before the middle Jurassic sedimentation, there was compression and folding in the middle Neoproterozoic. The formation of about 1.200m was deposited in the Middle Jurassic, which made the Ro value of source rocks reach about 1.0% and entered a large number of hydrocarbon generation stages, which was the main hydrocarbon generation period in the middle Neoproterozoic and the main migration and accumulation period. Since then, it is mainly compression uplift, and the reservoir is in the stage of preservation and adjustment. Its oil and gas reservoirs belong to primary hydrocarbon generation type.
(4) Resource prospect
The hydrocarbon generation intensity of Mesoproterozoic reached 600× 104t/km2. According to the preliminary calculation, the resource amount is 2. 1× 108t, and the resource abundance is 7× 104t/km2.
2. Jingxi area
Located in the western suburbs of Beijing, the northeast is covered by Quaternary, and the southwest is covered by Mesozoic and Paleozoic. The uplift area is a Ⅲ-level superposition unit, and the depression area is a Ⅱ-level superposition unit. Mesoproterozoic is well preserved, with an exploration area of more than 2,000 km2.
The recognized structure is the Kunming Lake anticline structure. In addition, there are some anticline structures composed of Paleozoic in the western mountainous areas. For example, the southwest extension of Kunming Lake structure may be the highest point of this anticline. But these areas have only been surveyed on the ground, and the degree of exploration is very low, which is a blank area for oil exploration.
(1) source-reservoir-cap assemblage
The main source-reservoir-cap assemblage is located under the shale of the Middle and Lower Cambrian, and the two sets of regional reservoir-cap assemblages of the Mesoproterozoic and Neoproterozoic are well preserved. The average organic carbon of shale is about 1.5%, and the evolution degree of source rocks is high, with the upper part reaching the wet stage and the middle and lower part possibly reaching the methane gas stage. As a caprock, Xiamaling Formation is over 200 meters thick and well preserved.
(2) Resource potential
Mesoproterozoic hydrocarbon generation intensity is greater than 1000× 104t/km2. According to the preliminary calculation, the resource amount is 1.6× 108t, and the resource abundance is 8.0× 104t/km2.
3. Central and Northern Hebei Province
Including Langgu sag, Wuqing sag and Yangcun slope in the north-central Hebei Province, with an exploration area of 6000km2, it is a Mesoproterozoic buried area, with I-type superimposed unit as the main part and complete source-reservoir-cap assemblage. There are two favorable zones: Tongbaizhen fault rising plate, with an area of about 550km2；; This zone is located in the east of Wuqing sag, with an area of about 400km2.
Meichang buried hill is a perfect trap in the east of Wuqing sag, with a trap area of 30km2. The closed amplitude is 300m, and the buried depth of the high point is 500m.
(1) source-reservoir-cap assemblage
The main caprocks are shallow-sea mud flat sedimentary strata of the Cambrian Mantou Formation, Maozhuang Formation and Xuzhuang Formation, mainly shale mixed with marl, with a thickness of more than 200m, which can form a 1 set of reservoir-cap combination with the underlying dolomite of Fujunshan Formation, limestone of Qingbaikou Jingeryu Formation and sandstone of Changlongshan Formation. Shale of Xiamaling Formation is the second complete source-reservoir-cap assemblage composed of source rocks, underlying Tieling Formation reservoirs and Hongshuizhuang Formation source rocks. The source reservoir of Wumishan Formation and the overlying source caprock of Hongshuizhuang Formation form the third source reservoir cap assemblage (Figure 6- 1-5). The possible unfavorable factor in this zone is that the evolution degree of source rocks in Yanshan period is relatively high (Ro is greater than 1.6%), while traps are mostly formed in the late Yanshan period and Paleogene period, and the matching conditions between structural formation period and hydrocarbon generation peak period are poor.
Fig. 6- 1-5 well Neoproterozoic source-reservoir-cap assemblage histogram
(2) Resource potential
The intensity of hydrocarbon generation in Mesoproterozoic was (400 ~ 500) × 104t/km2, and the maximum was over 600× 104t/km2. The preliminary estimate of resources is 2.4× 108t, and the resource abundance is 4. 1 × 100t.
(2) Paleozoic strategic region
The Paleozoic * * * is divided into five blocks: the central part of Northeast Hebei, the south-central part of Huanghua, Linqing (east-west), Dongpu Depression and Jiyang Depression (Figure 6- 1-6, Figure 6- 1-7, Table 6- 1-6). There are two secondary areas: central Hebei, northeastern Hebei and Jiyang depression.
1. Central and Northeast Hebei
It is located in the west of Cangxian uplift and east of Langfang-Yongqing line, with an area of about 5500km2 (Figure 6- 1-8). Wuqing sag is a type Ⅰ superimposed unit, and Su Qiao-Wen 'an area is a type Ⅱ 2 superimposed unit.
(1) source-reservoir-cap assemblage
The main source rocks are Ordovician limestone and Carboniferous-Permian coal and mudstone. The middle-upper Ordovician source rocks are about 60m thick and the residual organic carbon content is about 0. 12%, which belongs to poor source rocks. The carboniferous Shanxi Formation coal seam is about 20m thick, and the dark mudstone is 200m thick, and the organic carbon content of dark mudstone is 2.5% ~ 5.0%. The reservoirs are Ordovician weathering crust and Permian Shihezi Formation sandstone. The overlying Carboniferous-Permian coal measures mudstone is the caprock.
(2) Oil and gas generation
The Ordovician has secondary hydrocarbon generation conditions, with the hydrocarbon generation intensity of (10 ~ 20) × 104t/km2 in Yanshan period and (40 ~ 80) × 104t/km2 in Himalayan period. Total hydrocarbon generation intensity: oil 120× 104t/km2, natural gas 280× 104t/km2.
The hydrocarbon generation intensity of Carboniferous-Permian coal measures source rocks in Yanshan period is (50 ~ 100) × 104t/km2, and that in Himalayan period is (100 ~ 250 )×104t/km2, with a total hydrocarbon generation intensity of 250.
Fig. 6- 1-6 Comprehensive Evaluation Map of Lower Paleozoic in East North China
Figure 6- 1-7 Comprehensive Evaluation Map of Upper Paleozoic in East North China
Table 6- 1-6 Basic Parameters and Evaluation Table of Paleozoic Block
Figure 6- 1-8 Comprehensive Achievement Map of Paleogene in Jizhong Depression
(3) Preservation conditions
The thickness of bauxite at the top of Ordovician weathering crust is generally more than 5m, and the maximum is 18m. The thickness of mudstone caprock is150 ~ 200m, which is a good caprock type. The reverse fault has good sealing conditions, and the sealing conditions of Su Qiao buried hill and Sicundian wharf structural belt near the center of the depression are better.
(4) Reservoir-forming model
It is a I-type superimposed unit for secondary accumulation, and the main accumulation period is Himalayan period, which matches the structural formation period and can form Ordovician weathering crust structural oil and gas reservoirs, Carboniferous-Permian structural oil and gas reservoirs and lithologic oil and gas reservoirs.
(5) Resource potential
It is estimated that the Cambrian-Ordovician resources are 0.4× 108t and the resource abundance is 0.7× 104t/km2. The Carboniferous-Permian resources are 0.9× 108t, and the resource abundance is 1.7× 104t/km2. The total resources are 1.3× 108t.
At present, the Sicundian-Wharf structural belt has been discovered. The trap area of Lower Paleozoic in Sicundian Buried Hill is 80km2, the closed range is 700m, and the buried depth of high point is 6300m. ..
2. South central Huanghua
It covers an area of 4 100km2 from the south of Kongdian Uplift to Dongguang and from east to west to the boundary of Huanghua Depression (Figure 6- 1-9). Wuqiao and Nanpi sag are type ⅰ superimposed units, Cangdong sag is type ⅱ2 superimposed units, and Kongdian structure and Xuhei structural belt are type ⅱ 1 superimposed units.
(1) source-reservoir-cap assemblage
The source rocks are Ordovician limestone and Carboniferous-Permian coal and mudstone, in which the upper Ordovician source rock is 120m thick, the organic carbon content is 0.2%, the Carboniferous-Permian coal seam is 12 ~ 30m thick, with an average of about 20m, and the dark mudstone is 80 ~ 120m thick. The organic carbon content of dark mudstone is more than 2.0%, and the Ro is 1.5%. The main reservoirs are the weathering crust at the top of Ordovician and Permian sandstone, and the caprock is Carboniferous-Permian coal measures mudstone.
(2) Oil and gas generation
The hydrocarbon generation intensity of Ordovician source rocks in Yanshan period is (40 ~ 80 )× 104t/km2, and that in Himalayan period is (40 ~ 100 )× 104t/km2, and the total hydrocarbon generation intensity is (120 ~ 200).
The hydrocarbon generation intensity of Carboniferous-Permian coal measures source rocks in Yanshan period is (100 ~ 200 )×104t/km2, and that in Himalayan period is (100 ~150 )×104t/km2.
(3) Preservation conditions
The thickness of bauxite at the top of Ordovician weathering crust is generally more than 5m, up to 20m, and the thickness of mudstone caprock is 150~250m ~ 250m, which is a good caprock. The Kongxi, Wang Guan Tun and Wumaying structures in this structural belt have no major faults, and the fault distance is small, mainly reverse faults, with good sealing.
(4) Reservoir-forming model
It belongs to the secondary hydrocarbon generation and accumulation type of type ⅰ superimposed unit, and part of it belongs to the secondary hydrocarbon generation and accumulation type of type ⅱ2 superimposed unit. The hydrocarbon generation in Yanshanian and Himalayan periods is relatively large, and the oil and gas generated in Himalayan period is more conducive to reservoir formation. Wumaying and Wang Guan Tun belong to inherited paleo-uplift, and the Yanshanian denudation is weak, which can capture the oil and gas generated in Yanshan and Himalayan periods, while Kongxi structure was mainly formed in Himalayan period, and most of the oil and gas accumulated in Yanshan period was destroyed. For example, the asphalt of Konggu 3 well was formed by the destruction of ancient oil reservoirs formed in the early stage.
(5) Resource potential
The Cambrian-Ordovician resources are estimated to be 1.3× 108t, and the resource abundance is 3.2× 104t/km2. The Carboniferous-Permian resources are 1.3× 108t, and the resource abundance is 3.3× 104t/km2. The total resources of Paleozoic are 2.6× 108t.
At present, favorable buried hill structural belts such as Wang Guan Tun, Kongxi, Wumaying and Xuhei have been discovered, among which Well Konggu 3 in Kongxi structural belt has obtained an Ordovician industrial oil flow.
Fig. 6- 1-9 Comprehensive Achievement Map of Palaeozoic in Huanghua Depression
3.Linqing Depression
The tectonic location belongs to the south of Bohai Bay Basin, the south of Xinhe-Longyao Uplift, the north of Neihuang Uplift, the west of Luxi Uplift and the east of Taihang Mountain Uplift, including eight fault depressions, namely Shenxian, guanxian, Qiuxian, Daying Town, Nangong, Julu, Nanhe and Handan, as well as Tangyi, Wucheng, Guantao, Minghuazhen, Xinhe, Guangzong Uplift and Jize and Cheng 'an Low Uplift. Area 18000km2, of which the area in the east of Linqing is 6800km2, and the area in the west of Linqing is 1 1200km2 (Figure 6- 1- 10). From the Paleozoic oil and gas display, the eastern part is better than the western part. Among the exploration wells in the west 18, only Ju 1 well saw 0.25m oil spot, and Ju 2, Xin Ju 5 and Guantao 1 well showed fluorescence in Ordovician, and Guantao 1 well produced water after testing, with a small amount of combustible gas. Oil and gas show is active in the east since Tang Yilong, and 12 wells have been drilled (Gaogu 1, 4, 7, Kanggu 1, 2, 4, Tanggu 1, 3, 4, 5, Xin 3 and Hua 4), among which 7 wells have oil spots.
Shenxian, guanxian, Qiuxian, Julu, Handan, Nangong and Dayingzhen depressions are type I superimposed units, while Tangyi, Guantao and Guangzong bulges are type II1,and other areas are type III superimposed units.
Figure 6- 1- 10 Comprehensive Achievement Map of Pre-Paleogene in Linqing Depression
(1) source-reservoir-cap assemblage
The Ordovician source rock thickness in the east of Linqing is 120 ~ 150 m, and the organic carbon content is 0.2%. The source rocks in the west of Linqing are about 45m thick, and the organic carbon content is less than 0. 18%. Carboniferous-Permian coal seam thickness 10 ~ 17m, dark mudstone about 100m. The regional reservoir is the ancient weathering crust at the top of Ordovician, and the pay zones are mostly concentrated near the top of Ordovician, so wells that encounter weathering crust often lose circulation. For example, the Ordovician in Well Shen 3 lost 2130 ~ 3,370.5m * * * mud+0.6m3, and the Ordovician in Well Hua 4 lost 2,869.438+0.5 ~ 2,908. Carboniferous-Permian reservoir has the best physical properties, followed by Xiashihezi Formation sandstone, and Shanxi Formation and Taiyuan Formation sandstone also have certain storage capacity. According to conventional analysis, the porosity of argillaceous fine-medium grained lithic sandstone in Taiyuan Formation of Well Gaogu 4 is 3.8%, and the horizontal permeability is 0.047× 10-3μm2. The caprock is Carboniferous-Permian coal measures mudstone.
(2) Oil and gas generation
The hydrocarbon generation intensity of Ordovician in eastern Linqing is (40 ~ 80) × 104 t/km2, and that of Himalayan is1×104t/km2, which can reach 80× 104t/km2 in Shenxian sag. The total hydrocarbon generation intensity is (65438). The Ordovician hydrocarbon generation intensity in the west of Linqing is (20 ~ 40) × 104t/km2, and it is less than 10× 104t/km2 in Himalayan period. Handan sag is large, and the total hydrocarbon generation intensity is about 50× 104t/km2.
The hydrocarbon generation intensity of Carboniferous-Permian in western Linqing is 100× 104t/km2, and the main hydrocarbon generation period is Yanshanian. The hydrocarbon generation intensity of Carboniferous-Permian in eastern Linqing is 120× 104t/km2, and the main hydrocarbon generation periods are Yanshan and Himalayan.
(3) Preservation conditions
The thickness of bauxite at the top of Ordovician weathering crust is generally 5 ~ 8m, and the thickness of mudstone caprock is 100 ~ 200m, which is a good caprock type. However, Guantao Uplift and Tangyilong have large faults and large fault distances, mainly along faults, and poor sealing. However, the east-west structural belt from Tangyilong was well preserved in Paleozoic and the fault sealing was good. Mudstone is developed in Xiaofu reach of Shihezi Formation, with a thickness of 80 ~ 150 m, accounting for about 70% of the thickness of the stratum, which can be used as a good regional caprock. In addition, the mudstone in the concentrated section of Carboniferous coal measures can also be used as the direct caprock of underlying sandstone reservoirs, and the direct caprock of Taiyuan Formation gas reservoir in Gaogu 4 well is the mudstone of Taiyuan Formation itself.
(4) Reservoir-forming model
It is mainly of type I superimposed unit secondary hydrocarbon generation and accumulation type, and Guantao uplift and the top of Tangyilong are of type II 1 superimposed unit secondary hydrocarbon generation and accumulation type.
(5) Resource potential
The Cambrian-Ordovician resources in Linqing area are 2.4× 108t, and the resource abundance is 1.3× 104t/km2. The Carboniferous-Permian resources are 1.3× 108t, and the resource abundance is 1.5× 104t/km2. The total resources in Paleozoic were 4.7× 108t, and the resource abundance was 2.8× 104t/km2.
Tangyi structural belt and Guantao structural belt are relatively solid. The former has active oil and gas display, but poor preservation conditions and serious fault damage. The latter has poor matching conditions: Guangzong-Julu area belongs to Indosinian paleouplift, and traps formed early, but the source rocks did not enter the peak of hydrocarbon generation. The source rocks of Qiuxian sag-Guantao uplift reached maturity at the end of Yanshan period, while the structural traps were mainly formed in Himalayan period. Guantaodong structure and Tangyidong structure have good preservation conditions, but the structures need to be further implemented.
4. Dongpu Depression
Dongpu area covers an area of 3,500km2 (Figure 6-1-1). Oil and gas show in Carboniferous-Permian 17 well, and industrial oil and gas flow in Wen Gu 2 well. Low-yield oil was obtained in Well Kai 33, Well Kai 35, Well Wen Gu/KLOC-0 and Well Bai 56. 23 wells have seen good oil and gas display in Cambrian-Ordovician. The Carboniferous-Permian natural gas of Liu Wen and Hubuzhai was discovered in Paleogene and Mesozoic.
There is no Jurassic-Cretaceous distribution in this area, which is mainly ⅱ-4 superimposed unit, and the inner yellow uplift is grade ⅲ.
(1) source-reservoir-cap assemblage
The upper Ordovician source rocks are160m thick and the organic carbon content is 0.30%. The thickness of Carboniferous-Permian coal seam is generally about 13m, the thickness of dark mudstone is generally about 150m, and the average organic carbon content of mudstone is 1.7%. The main reservoirs are Ordovician, Carboniferous-Permian, Mesozoic and Paleogene. In addition to Paleozoic caprock itself, gypsum developed in Paleogene is also a high-quality caprock.
Figure 6- 1- 1 1 Comprehensive Achievement Map of Paleozoic in Dongpu Depression
(2) Oil and gas generation
The hydrocarbon generation intensity of Ordovician Indosinian-Yanshan period is (50 ~ 100) × 104t/km2, and Himalayan period is (10 ~ 40) × 104t/km2, and the total hydrocarbon generation intensity is104t/km2.
The hydrocarbon generation intensity of Indosinian-Yanshanian Carboniferous-Permian coal measures source rocks is (100 ~ 300 )×104t/km2, Himalayan hydrocarbon generation intensity is (120 ~ 200 )×104t/km2, with total hydrocarbon generation intensity.
(3) Preservation conditions
The thickness of bauxite at the top of Ordovician weathering crust is generally 4 ~ 8m, and the thickness of mudstone caprock is 100 ~ 150m, which is a good caprock type. However, all structural belts have large faults and the fault distance is large, so the sealing of Paleogene is very important. Except for the central uplift belt, the Paleozoic lateral sealing conditions in Pucheng in the north, Machang in the south, Hu Qing in the west and Gaoping structural belt are relatively poor.
(4) Reservoir-forming model
It belongs to the secondary hydrocarbon generation and reservoir formation type of I-type superimposed unit, and Himalayan period is the key period of reservoir formation.
(5) Resource potential
The Cambrian-Ordovician resources are 0.4× 108t and the resource abundance is 0.9× 104t/km2. The Carboniferous-Permian resources are 1.0× 108t, and the resource abundance is 2.9× 104t/km2. The total resources in Paleozoic were 1.4× 108t, and the resource abundance was 3.8× 104t/km2.
The division is divided into six favorable areas with a total area of 767km2. Among them, the coal-formed gas field of Carboniferous-Permian Paleogene reservoir was found in the Liuwen nose anticline structure in the central structural belt. The structural zone area of Machang fault block is 100km2, and 20 wells have been drilled, only well Magu-5 has low gas flow. The northern part of the central uplift belt in Dongpu Depression is dominated by anticlines and fault nose traps, with a trap area of over 60km2 and a low degree of exploration, which is a favorable structural belt.
5. Jiyang Depression
Jiyang depression includes four main depressions: Huimin, Dongying, Chezhen and Zhanhua. Huimin sag and Zhanhua sag have the best reservoir-forming conditions in Paleozoic. The total resources of Carboniferous-Permian are 3.0× 108t, including oil 1.0× 108t and natural gas 2.0×108t; ; The total resources of Cambrian-Ordovician are 1.0× 108t, including 0.5× 108t for oil and 0.5× 108t for natural gas. The total resources of Paleozoic are 4.0× 108t, including oil 1.5× 108t and natural gas 2.5× 108t.
(1) Huimin District
Located in the southwest of Jiyang Depression, on the north slope of Luxi Uplift, with an area of 2000km2. The Qugu 1 well fault block obtained industrial gas flow from Carboniferous to Permian Paleogene Shahejie Formation. The southern slope of Huimin is a slope belt inclined to the north formed from Eocene to Oligocene. Due to the continuous activities of secondary or sub-secondary faults such as Xiakou, Qihe, Baiqiao and Qu Di, the southern slope is divided into three structural zones: Xiakou gentle slope zone, Qu Di graben zone and Wangjudeng buried hill zone. Due to sedimentary discontinuity, stratum denudation, fault structure development and the interaction of various sand bodies and igneous rocks, various types of traps have been formed on the south slope. Mainly I-type superposition unit.
1) source-reservoir-cap assemblage. The thickness of Cambrian-Ordovician source rocks is more than 40m, and the organic carbon content is about 0. 12%. Carboniferous-Permian coal seam thickness 14~34m, with an average of about 20m, dark mudstone thickness 14 ~ 34m, and mudstone organic carbon content of 2.5% ~ 3.0%. Paleozoic reservoirs include Ordovician dolomite, top weathering crust and Permian sandstone. There are two sets of regional caprocks, namely, Carboniferous-Permian dark mudstone and coal measures strata and Mesozoic lower Jurassic coal measures strata.
2) Hydrocarbon generation. The hydrocarbon generation intensity of CAMBRIAN-Ordovician is 50×104t/km2; The hydrocarbon generation intensity of Carboniferous-Permian coal measures source rocks in Yanshan period is (100 ~150 )×104t/km2, and in Himalayan period it is (80 ~ 150) × 104t/km2, with total hydrocarbon generation.
3) Save conditions. The thickness of bauxite at the top of Ordovician weathering crust is about 4m, and the thickness of mudstone caprock is 100m, which is a good caprock type, with developed forward faults and poor lateral sealing conditions. Generally speaking, the Paleozoic preservation conditions were general.
4) Reservoir-forming mode. It is a type I superimposed secondary reservoir, and Yanshanian and Himalayan periods are important hydrocarbon generation and reservoir formation periods.
5) Resource potential. The Cambrian-Ordovician resources are 0.5× 108t, and the resource abundance is 2.2× 104t/km2. The Carboniferous-Permian resources are 1.4× 108t, and the resource abundance is 6.6× 104t/km2. The total resources in Paleozoic were 1.9× 108t, and the resource abundance was 8.8× 104t/km2.
(2) Zhanhua area
Located in the northern edge of Jiyang Depression, with an area of 2200km2. A favorable oil-bearing structural belt with an area of 160 km2 has been found in Gubei low buried hill. Four gas-bearing structures have been established in the area, with a trap area of 50 square kilometers and an amplitude of 800 meters. Three wells have been drilled 13, including Gubei 132, 136 and 1 well to obtain industrial oil and gas flow.
1) source-reservoir-cap assemblage. The upper Ordovician source rocks are 100 m thick and the organic carbon content is 0. 12%. Carboniferous-Permian coal seam is 29m thick, dark mudstone is 300m thick, and the organic carbon content of dark mudstone is 2.36%. The reservoirs are Ordovician weathering crust and Permian sandstone; The caprocks are Carboniferous-Permian coal measures mudstone and Mesozoic coal measures mudstone.
2) Hydrocarbon generation characteristics. The hydrocarbon generation intensity of CAMBRIAN-Ordovician is 50×104t/km2; The hydrocarbon generation intensity of Carboniferous-Permian coal measures source rocks in Yanshan period is 10× 104t/km2, and that in Himalayan period is (100 ~150 )×104t/km2, and the total hydrocarbon generation intensity is/kloc.
3) Save conditions. The thickness of bauxite at the top of Ordovician weathering crust is generally 5 ~ 15 m, and the thickness of mudstone caprock is 200 ~ 250 m, which belongs to a good caprock type. The trap was formed early, and the fault controlling the trap stopped moving in the late Paleogene, which has good sealing conditions.
4) Reservoir-forming mode. It is a ⅱ-2 superimposed secondary reservoir, and the main reservoir-forming period is Neogene, and the trap formation is earlier than a large number of hydrocarbon-generating periods, with good matching conditions.
5) Resource potential. The Cambrian-Ordovician resources are 0. 1× 108t, and the resource abundance is 0.5× 104t/km2. The calculated resources of Carboniferous-Permian are 0.7× 108t, and the resource abundance is 3.3× 104t/km2. The total resources in Paleozoic were 0.8× 108t, and the resource abundance was 3.8× 104t/km2.
(3) Mesozoic strategic location
According to Mesozoic superimposed unit types and hydrocarbon generation conditions, three strategic areas were selected. The first area is the eastern part of Liaohe River, and the second area is the central and western Bohai Sea and Zhanhua-Yellow River Estuary (Figure 6-1-12; Table 6- 1-7).
Figure 6- 1- 12 Comprehensive Evaluation Map of Mesozoic in East North China
Table 6- 1-7 Basic parameters and evaluation table of Mesozoic block
1. Eastern Liaohe River
The eastern part of Liaohe River covers an area of 3300km2 and is a long and narrow depression (Figure 6- 1- 13). The maximum buried depth of the basement is 9000m, and there are four negative structural zones from north to south: Qinglongtai-Changtan sag, Yujiafangzi sag, Jiazhangsi sag and Erjiegou-Gaizhoutan sag. The sag belongs to Ⅱ 2 type superposition unit, and the eastern uplift zone belongs to Ⅱ 3 type superposition unit.
Figure 6- 1- 13 Comprehensive Achievement Map of Mesozoic in Liaohe Fault Depression
Faults are developed in the sag, all of which are NE-trending normal faults, * *10, and there are two first-class faults, Yingkou fault and Tongerbao fault, which are the boundary faults with the eastern bulge; There are 8 secondary faults, namely Erjiegou fault, Huangxi fault, Cixi fault, Cidong fault, Rongxi fault, Jiadong-Jiexi fault, Jiaxi-Huangyu Redong fault and Jiedong fault, among which Erjiegou fault is the boundary fault of the central uplift of Liaohe fault depression. Mesozoic is only distributed to the east of Cidong fault, that is, to the east of the eastern depression.
(1) source rock
The upper part of Mesozoic is the Lower Cretaceous Lishugou Formation (equivalent to Jiufotang Formation in the western depression), which is mainly lacustrine dark mudstone, mainly composed of dark gray mud, shale, brown gray oil shale, limestone and sandstone, and is the main source rock in the eastern depression. The kerogen of Lishugou Formation is mainly type ⅰ and type ⅱ. Type ⅲ kerogen exists in Long 1 1 Well, and type ⅲ kerogen is the main kerogen in Tong 2 Well. Generally speaking, according to its type index, it should belong to ⅱ2 kerogen.
(2) Reservoir
Mainly Ordovician limestone. The porosity of Ordovician Majiagou Formation limestone in Wang Shen 1 Well is 2.8% ~ 7.4%, with an average of 4.43%. The minimum permeability is 1× 10-3μm2, and generally it is (3 ~ 9 )× 10-3 μ m2. Carboniferous-Permian sandstone has poor physical properties and low porosity and permeability. The average porosity is mostly between 3% and 6%, and the permeability is less than 1× 10-3μm2. The average porosity of Jurassic in Wang Shen 1 well is 8.7%, and the permeability is less than l× 10-3μm2. According to logging interpretation, the effective porosity of this group is 0. 1% ~ 3.6%, with an average of 0.52% and the permeability of (0 ~ 1.4) × 10-3 μ m2. The logging interpretation with an average value of 0.03× 10-3μm2 (Table 6-65438+) shows that the effective porosity of 398. 1 ~ 59 1.6m is 0.2% ~ 3 1.3%, with an average of 20.57%.
Table 6- 1-8 Statistics of Porosity and Permeability of Wang Shen 1 Well
Note: (1) Physical property analysis data of core samples; (2) Logging interpretation results.
(According to Liaohe Oilfield Exploration and Development Research Institute)
Table 6- 1-9 Data Table of Sand-Mud Ratio of Lishugou Formation
(According to Zhang Jinbo and others, 1995)
(3) caprock
Xiaodonggou Formation of Jurassic in Well Jie 3 is red silty mudstone and argillaceous siltstone with a thickness of 323 meters, which directly covers Ordovician. The thick Mesozoic can be used as the cover of Ordovician buried hill, and the Mesozoic can also form a combination of authigenic, self-storage and self-capping.
(4) Resource potential
The estimated resource amount is 1.9× 108t, and the resource abundance is11.4×104t/km2.
2. Central and western Bohai Sea
Include Qinnan sag, Shijiutuo uplift and Shinan sag. Qinnan sag and Shinan sag are the main hydrocarbon-generating sags in Mesozoic, and Shijiutuo uplift is the main target area.
Shijiutuo Uplift is located in the area with the largest remaining thickness in J3 -K, generally exceeding 2,000m and the thickest exceeding 3,000m ... It is surrounded by three depressions, namely Qinnan, Shinan and Bozhong. Shijiutuo Uplift belongs to Ⅱ 3 superposition unit, and the surrounding depression is Ⅰ superposition unit.
Source rock: Lower Cretaceous, mainly developed in Shijiutuo Uplift and Liaodong Bay, and the representative wells are Bozhong 6, Bozhong 14, JZ 16-2- 1. The lithology of Well Bozhong 6 is mainly dark gray and gray-black mudstone, with thin layers of calcareous mudstone, dolomite, sandy limestone and tuffaceous glutenite, and volcanic rocks 10 (1 ~ 2m thick). Borehole thickness is 89 1m, and mudstone content accounts for 27%. The organic carbon of the source rock in Well Bozhong 6 is low, but the S 1+S2 is above 1.0mg/g, and the highest is above 3.0 mg/g; the organic carbon content in Well JZ 16-2- 1 is more than 1.5%. The types of organic matter are all ⅱ 1-ⅱ2. More than 70% of these wells have Ro values ranging from 0.5% to 0.6%, belonging to low mature layers, and about 30% have Ro values less than 0.5%, belonging to immature layers.
At present, only Mesozoic reservoirs in Well N- 1 and Well Bozhong-6 and the first member of Shahejie Formation in QHD30- 1 have been discovered, indicating that Mesozoic has made great contributions to oil generation.
The above analysis shows that the Mesozoic source rocks in Bohai Sea can form effective oil and gas reservoirs, especially the traps near the hydrocarbon generation center have a high probability of forming reservoirs. Therefore, this region is a favorable strategic region.
The estimated resource amount is 1.3× 108t, and the average resource abundance is 4.0× 104t/km2.
3. Zhanhua-Yellow River Estuary Area
Including Zhanhua area and Huanghekou sag, with an exploration area of 5240km2.
There are two sets of source rocks in Zhanhua area: middle and lower Jurassic dark mudstone and coal, and upper Jurassic-lower Cretaceous dark mudstone. The middle and lower Jurassic coal seam is 6 ~ 3 1m thick, and the dark mudstone generally exceeds130m. . The upper Jurassic-lower Cretaceous dark mudstone has a small thickness, generally less than 10m (Table 6- 1- 10). Mesozoic igneous rocks from Upper Jurassic to Lower Cretaceous developed, as well as conglomerate and sandstone. Its own mudstone and overlying Paleogene-Neogene can be used as caprocks. The Huanghekou sag is deeply buried, and the oil and gas generated in Mesozoic can accumulate in its own reservoir or migrate through faults in Paleogene-Neogene.
Table 6- 1- 10 Statistical Table of Mesozoic Source Rock Thickness in Zhanhua Area
The total hydrocarbon generation intensity of Mesozoic is generally (50 ~ 200) × 104t/km2, and the total resource is 2.9× 108t.