Resource Evaluation of Nongan Oil Shale Mining Area (Anatomical Area) in Jilin Province

Nongan oil shale mining area is located in Songliao Plain, which is a part of Songliao Basin. Located in the north of Changchun, there is He Long in the south, Songhua River in the north, Qingshankou in the east and Yong 'an in the west, with a total area of about 1800km2. Geographical coordinates: east longitude 124 00' ~ 126 00', north latitude 44 00' ~ 45 20'. Roads and railways in the mining area extend in all directions and the traffic is very convenient.

I. Geological background

Structural characteristics of (1)

The structural framework of Songliao Basin consists of northern submerged area, northeast uplift area, southeast uplift area, central depression area, western slope area and southwest uplift area. On the whole, it is a form of alternating ridges and depressions. The dip angle of strata in the basin is relatively slow, ranging from 0 to12, which is steep only locally, but not more than 30, and there is no major fault structure in the basin. Nongan oil shale mining area is located in the southeast uplift area.

(2) Stratigraphic characteristics

The sedimentary caprock in Songliao basin is composed of Mesozoic and Cenozoic, with a total thickness exceeding10000 m.

1. Upper Jurassic Baicheng Formation (J3b)

This formation is mainly distributed sporadically in Baicheng City, Taonan Town and Heping 'an Town in the west of Jilin Province, and deposited in the intermountain basin. The main lithology is grayish green, grayish white sandstone, glutenite, grayish black mudstone, siltstone, siltstone mixed with gray and grayish purple tuff and thin coal seam, with tuffaceous conglomerate at the bottom and unconformity in Permian.

2. Cretaceous

The Lower Cretaceous includes Huoshiling Formation, Shahezi Formation, Yingcheng Formation, Denglouku Formation and Quantou Formation.

(1) Huoshiling Formation (K 1h).

Distributed in the southeast of the basin, it is a set of volcanic rocks and pyroclastic rocks deposited in the early stage of the basin fault depression. The lithology is mainly tuffaceous breccia, tuff, andesite, basalt and tuffaceous conglomerate, and the bottom angle is unconformity in Jurassic.

(2) Shahezi Formation (K 1sh).

Widely distributed in all kinds of fault depressions in the basin, mainly a set of semi-deep limnetic deposits with relatively deep water bodies. Lithology is mainly grayish black and dark gray mudstone, with grayish white sandstone, siltstone and a small amount of tuff. It is in local unconformity contact with the underlying stratum.

(3) Yingcheng Formation (K 1y).

Widely distributed, a set of volcanic-terrigenous clastic coal-bearing sedimentary formations has developed. The main lithology is: the lower part is andesite basalt, volcanic breccia, tuffaceous sandstone and gray sandstone, glutenite and gray-black mudstone mixed with coal seam; The upper part is acidic volcanic rocks, pyroclastic rocks and sandstone, siltstone and black mudstone, containing minable coal seams, which are in integral or parallel unconformity contact with the underlying strata. Affected by three Yanshan movements, the top strata of Yingcheng Formation in some areas of the basin are missing.

(4) Denglouku Formation (K 1d).

It is a set of strata deposited in the transitional period of fault depression, and the lithology of the lower part is mainly gray-white variegated glutenite, mixed with gray-green and purple mudstone and a small amount of tuff; The upper part is interbedded with green and grayish brown mudstone and variegated glutenite. It is in angular unconformity contact with the strata of Xiafuyingcheng Formation. Some strata of Denglouku Formation are missing in some areas of the western slope.

(5) Quantou Formation (K 1q).

It was deposited in the early depression of Songliao Basin. The river facies is dominant in the basin, and the grain size becomes thicker towards the edge of the basin. According to lithology, it can be divided into four sections: Quanyi section is mainly composed of purple-gray, gray-white glutenite and purple mudstone interbedded, with a small amount of tuff locally; The second member of Quan is mainly purplish red and maroon mudstone mixed with purplish gray and grayish white sandstone. The third member of Quan is mainly composed of gray-green, purple-gray powder, fine sandstone and purple mudstone interbedded; The fourth member of Quan is grayish green and grayish white toner, with fine sandstone mixed with purplish red and brownish red mudstone, and the top is often grayish green mudstone. Quantou Formation is in conformity-parallel unconformity contact with the underlying Denglouku Formation. The basin margin often overlaps with the old strata at different horizons.

The Upper Cretaceous in Songliao Basin includes Qingshankou Formation, Yao Jia Formation, Nenjiang Formation, Sifangtai Formation and Mingshui Formation.

(6) Qingshankou Formation (K2qn).

It is a period of relatively large sedimentary range in Songliao basin, and the lower part is mainly composed of deep lake-semi-deep lake mudstone and shale, with oil shale; The upper part is black and dark gray mudstone mixed with gray and gray-green calcareous siltstone and multi-layer ostracods. The lateral coarse debris of this group increased, and it was in conformity-parallel unconformity contact with the underlying Quantou Formation. Paleontological studies have found that the top of Qingshankou Formation in the western slope belt may be missing, and the top of Qingshankou Formation in Lishu fault depression has also been eroded.

(7) Yao Jia group (K2y).

The stratum is mainly composed of purplish red, brownish red, grayish green mudstone and grayish white sandstone. Black mudstone can be seen in the middle of the basin, which is in conformity-unconformity contact with the underlying Qingshankou Formation. Yao Jia Formation is widely distributed in this area, but eroded in Lishu fault depression.

(8) Nenjiang Formation (K2n).

It is the most widely distributed stratum in the basin, which has exceeded the northern and northeastern boundaries of the basin. The lower lithology is mainly black and gray-black mudstone and shale, with oil shale layer; The upper part is interbedded with grayish green, dark gray and brown mudstone, siltstone and fine sandstone. Nenjiang Formation is in integral contact with the underlying Yao Jia Formation. Due to the influence of the four acts of Yanshan movement in the late Nenjiang Formation, the upper part of Nenjiang Formation was partially denuded in some areas on the western slope, and the Dehui fault depression and Lishu fault depression were completely denuded.

(9) Sifangtai Group (K2s).

It belongs to the shrinking period of the basin, the distribution range is greatly reduced, and the sedimentary center also moves to the west of the basin, mainly distributed in the central and western parts of the basin, mainly shallow lakes and rivers. Its main lithology is: the lower part is brick red sandy mudstone mixed with fine gravel mixed with brown gray sandstone and argillaceous siltstone; The middle part is interbedded with gray fine sandstone, siltstone, argillaceous siltstone, brick red and purple mudstone; The upper part is mainly red-purple mudstone, with a small amount of gray fine sandstone, mudstone and siltstone, which is in angular unconformity contact with the underlying Nenjiang Formation.

(10) Mingshui Formation (K2m).

The distribution range of Sifangtai Formation is more limited than that of Sifangtai Formation, mainly distributed in the central and western parts of the basin, and generally absent in the east. Lithology is mainly grayish green and grayish black mudstone, grayish green sandstone and argillaceous sandstone, which are in conformity-parallel unconformity contact with the underlying Sifangtai Formation. In addition to the distribution limitation, it is also partially missing in the western slope and Gan 'an sag.

3. Early Tertiary. Comparative NEOGENE

Mainly distributed in the west of Songliao Basin, it is divided into three groups from bottom to top: Yian Formation, Daan Formation and Taikang Formation. Yi 'an Formation is 100 m thick, which is a large cross-bedded fine sandstone containing plant fossils. Daan Formation is 260m thick, with yellow-gray mudstone and silty mudstone at the upper part and gravel layer at the bottom. Taikang Formation is the most widely distributed, and its main lithology is a set of grayish green, yellowish green and dark gray mudstone mixed with sandstone and conglomerate, which is in angular unconformity contact with the underlying stratum.

4. Quaternary system

The sediments are developed, with a thickness of10 ~ 200m, and are mainly composed of aeolian sediments and river sediments. The lithology is mostly loess loam, black loam, sandy soil and gravel layer, which is in parallel unconformity-angular unconformity contact with the underlying Paleogene.

(3) Igneous rocks

Magmatic activities in this area are mainly concentrated in Huoshiling Formation and Yingcheng Formation of Lower Cretaceous, and basalt erupts and accumulates locally in Upper Cretaceous, which has no influence on the deposit.

Second, the characteristics of oil shale

(A) the physical characteristics of oil shale

Nong 'an oil shale is generally grayish brown, gray striped, conchoidal fracture, argillaceous structure, dense massive structure, rarely flaky, knife-rolled, smoked, and has a strong asphalt smell.

(2) Technical characteristics of oil shale

The oil content of oil shale in Nong 'an oil shale mining area is moderate, with the highest oil content reaching 12. 10%, generally around 5%. According to the industrial indexes of low-temperature dry distillation test, the water content of oil shale is 1.95%-4.83%, the ash content is 77.7 1%-94.48%, and the volatile content is11.74%-18.43. Through the linear regression analysis of the data, we found that the oil content of oil shale has obvious correlation with ash content and oil content with calorific value (Figure 5- 1 1, Figure 5- 12).

Table 5-9 List of Oil Shale Characteristics in Nongan Oil Shale Mining Area

Fig. 5- Relationship between oil content and ash content of oil shale +0 1

Fig. 5- 12 Relationship between oil content and calorific value of oil shale

These include:

1. Correlation between oil content and calorific value

(1) Oil shale exploration area in Nong 'an area.

The correlation coefficient between oil content and calorific value is 0.86, and the established linear regression equation is y =-662.88+334.55x.

(2) Oil shale exploration area around Nong 'an.

The correlation coefficient between oil content and calorific value is 0.95, and the established linear regression equation is y = 0.15+172.85x.

(3) Xiaohelong oil shale exploration area.

The correlation coefficient between oil content and calorific value is 0.79, and the established linear regression equation is y =184.57+128.45438+0x.

(4) Denglouku oil shale exploration area.

The correlation coefficient between oil content and calorific value is 0.87, and the established linear regression equation is y =125.91+134.5438+0x.

Through the correlation analysis between oil content and calorific value, it is found that the higher the oil content, the higher the calorific value. In the established linear regression equation, y represents oil content and x represents calorific value.

2. Correlation between oil content and ash content

(1) Oil shale exploration area in Nong 'an area.

The correlation coefficient between oil content and ash content is 0.86, and the established linear regression equation is y = 91.51-1.37x.

(2) Oil shale exploration area around Nong 'an.

The correlation coefficient between oil content and ash content is 0.89, and the established linear regression equation is y = 90.57-1.39x.

(3) Xiaohelong oil shale exploration area.

The correlation coefficient between oil content and ash content is 0.94, and the established linear regression equation is y = 91.93-1.74x.

(4) Denglouku oil shale exploration area.

The correlation coefficient between oil content and ash content is 0.62, and the established linear regression equation is y = 87.52-1.08x.

Through the correlation analysis between oil content and ash, it is found that the higher the oil content, the lower the ash yield. In the established linear regression equation, Y represents oil content and X represents ash yield.

(III) Types and geochemical properties of oil shale

1. Genetic types of oil shale

Through the identification and classification of sporopollen, the analysis of kerogen maceral, chemical elements and pyrolysis parameters, it is concluded that Nong 'an oil shale is sapropelic and humic sapropelic. Among them, the sapropelic group is mainly amorphous and its fluorescence is weak. The content of oil shale crusts is very small, with occasional crustaceous debris and sporophytes; The content of inert components is also very small, mainly a small amount of filaments. Through the analysis of H/C atomic ratio and O/C atomic ratio, the H/C atomic ratio is 0.65 ~ 1.75, and the O/C atomic ratio is 0.0 1 ~ 0. 12. Therefore, the oil shale in Nong 'an oil shale mining area belongs to I-II kerogen, with high original hydrogen content and low oxygen content.

2. Maturity of oil shale

The maturity of oil shale mainly depends on the sign of clay minerals, pyrolysis parameters and vitrinite reflectance of oil shale. X-ray diffraction analysis shows that the main clay minerals of oil shale in Nong 'an mining area are illite and montmorillonite, followed by illite-montmorillonite mixed layer and kaolinite. The vitrinite reflectance of oil shale in Nong 'an mining area is generally around 0.5. According to the evolution model of organic matter and hydrocarbon generation stage, most of the organic matter in oil shale in China is diagenetic stage, which is equivalent to the immature stage of Huang Difan (199 1). According to pyrolysis analysis, the oil shale in Nong 'an oil shale mining area is generally tmax (℃).

3. Characteristics of organic chemical elements in oil shale

According to the analysis of organic elements, C, H, N and other elements in Nong 'an oil shale mining area have certain correlation with the oil content of oil shale (Figure 5- 13, Figure 5- 14, Figure 5- 15).

Fig. 5- 13 relationship between oil content of oil shale and c

Fig. 5- 14 Relationship between oil content of oil shale and H.

Fig. 5- 15 Relationship between oil content and nitrogen in oil shale

Through the linear regression analysis of the data, it is found that the oil content of oil shale is positively correlated with elements C, H and N, but the correlation between oil content and element S is not obvious (Figure 5- 16).

Fig. 5- 16 Relationship between oil content and sulfur in oil shale

Iii. Mineralization and distribution of oil shale

(A) the occurrence characteristics of oil shale

1. Oil shale occurrence horizon

Oil shale is developed in Qingshankou Formation and Nenjiang Formation of Cretaceous. Qingshankou Formation is divided into three sections from bottom to top, and only the first section of Qingshankou contains oil shale layer, which is gray-black mudstone and shale mixed with oil shale. Nenjiang Formation is divided into five sections from bottom to top, with oil shale only developed at the bottom of the first and second sections (Table 5- 10).

Table 5- 10 Stratigraphic Characteristics of Qingshankou Formation and Nenjiang Formation in Nongan Oil Shale Mining Area

2. Occurrence characteristics of oil shale

The oil shale in the area is layered, and the buried depth of oil shale in the mining area (exploration area 7 ~ 258 m) increases to the center of the basin, with the maximum value of about 2000 m. The oil shale in Qingshankou Formation is developed in the whole area, only in Qingshankou anticline and Denglouku anticline, while the oil shale in other areas is undeveloped due to deep burial and shallow exploration depth. The oil shale formation of Nenjiang Formation is denuded in Qingshankou anticline and Denglouku anticline, and there is no oil shale of Nenjiang Formation in these two areas. The first member of Qingshankou Formation and the first and second members of Nenjiang Formation are all produced at the bottom of each member. The distance between Qingshankou Formation and Nenjiang Formation is 300 ~ 600 m, generally 400m m. The distance between Nenjiang Formation and Nenjiang Formation is 40 ~ 70m, generally 50m, which is relatively stable. The occurrence of oil shale is consistent with the formation occurrence, and the dip angle is gentle, generally not exceeding 10 (Table 5-11; Figure 5- 17, Figure 5- 18).

Table 5- 1 1 List of Occurrence Characteristics of Oil Shale Orebodies in Nongan Oil Shale Mining Area

Fig. 5- 17 isoline map of oil shale thickness in Nong 'an-Changling-Denglouku oil shale mining area (K2QN 1-b)

Fig. 5- 18 isoline of oil shale thickness in Nong 'an-Changling-Denglouku oil shale mining area (K2N2-B)

(2) Formation environment of oil shale

1. Tectonic background

Songliao Basin is a large depression basin and an important oil-gas bearing basin in China. The ore-bearing area is located in the southeast uplift area of Songliao Basin, bordering Wang Fu sag in the north, Diaoyutai uplift in the south, Qingshankou anticline in the east and Denglouku anticline in the west.

The sequence stratigraphy of Songliao continental rift basin is mainly controlled by the change of lake level (datum level), which is a function of structure, climate and sediment supply, and tectonism has a great influence on low-frequency sequences (mainly refers to first-order and second-order sequences). According to the sequence identification marks, the giant sequences in Songliao Basin are further divided into 3 supersequence groups, 7 supersequences, 19 sequences and a series of system tracts.

The oil shale developed in the first member of Qingshankou Formation and the second member of Nenjiang Formation is mainly located in the post-fracture thermal subsidence supersequence group, which is distributed all over Songliao Basin. The lower interface (T4) and the upper interface (T30) are angular unconformity, including fault depression transformation supersequence, lower depression supersequence and upper depression supersequence. The first member of Qingshankou Formation and the second member of Nenjiang Formation are developed in the lower and upper parts of the depression supersequence respectively, which are equivalent to XI and XV sequences.

2. Sedimentary environment

(1) Lake level change.

On the basis of seismic data interpretation and datum level analysis of single well and combined well, the datum level fluctuation curve of Songliao Basin is compiled by comprehensive application of various methods. The thick black oil shale developed in the first member of Qingshankou Formation and the second member of Nenjiang Formation corresponds to the two largest lake transgressions in the datum change curve of Songliao Basin, which indicates that the oil shale is the product of the two largest lake flooding periods in the basin.

① Quantou Formation-Qingshankou Formation. Quantou-Qingshankou Formation developed in the heyday of Songliao Basin, that is, the depression period. Due to long-term erosion, the terrain tends to be low, and the climate gradually turns warm and humid due to the previous drought and heat. Large-scale lake invasion developed in Quantou Formation-Qingshankou Formation in the basin, forming a large area of deep lake deposits. During the deposition period of K 1qn 1, the lake area reached 3 1× 105km2, and the semi-deep lake-deep lake sedimentary system was mainly developed in the basin, which directly overlapped with the shallow shore lake and alluvial system of K 1q4, and the flooding surface of the lake was located at k/kloc-.

② Yao Jia Formation-Nenjiang Formation. Yao Jia Formation-Nenjiang Formation is another well-developed sedimentary cycle in Songliao Basin after Quantou Formation-Qingshankou Formation, which has undergone an evolution of about 7Ma, and the basin is a whole depression. In the early stage of Yao Jia Formation, K2y 1, the depression of the basin subsided slowly, and the edge of the basin rose slightly at K2y 1, and the climate was dry and hot. At K2y2+3, it began to transform into temperature and humidity, and the vegetation was sparse, and the denudation area was mainly physical weathering. The lake area is only 9.8× 103km2, only1.85x104km2 away from the late K2y3. By K2n 1+2 of Nenjiang Formation, the subsidence rate of the basin was high, and the rapid subsidence led to another large-scale lake invasion event in Songliao Basin. In the late Nenjiang Formation, the subsidence rate of the basin slowed down, the lake area was continuously filled, and the lake area contracted, ending the deposition. The early sedimentary system was dominated by alluvial environment, and then suddenly transited to semi-deep lake/deep lake environment, and then gradually transited to alluvial environment through shore/shallow lake.

(2) sea level change.

According to a large number of research data, brackish water and brackish water biota (such as dinoflagellate, shark tooth and petabranchia) were found in Qingshankou Formation and Nenjiang Formation. Paleosalinity (Sr/Ba & gt；; 0.5、B/Ga & gt； 5) Other geochemical indicators also show that there is a marine sedimentary interlayer in Songliao Basin, which has a history of communication with the open sea. Therefore, the formation of oil shale is most likely due to the intrusion of seawater, which leads to the stratification of salinity density and the formation of anoxic environment.

Compared with the global sea level change curve of Haq, the datum level change curve of Songliao Basin has a higher coincidence degree in the form of quadratic curve. It further shows that two lake invasion events developed in the first member of Qingshankou Formation and the second member of Nenjiang Formation in Songliao Basin are related to the global sea level rise, which leads to the connection between lake and sea.

(3) Hypoxia events.

According to the research data at home and abroad, the formation conditions of black oil shale are often related to the lack of oxygen at the bottom of the basin. The anoxic environment of oil shale is related to the water layer. The core problem of water stratification is that lakes are stratified by density, and the density difference can be realized by temperature difference and salinity difference. Generally speaking, layered lakes formed by temperature difference are unstable and change with climate change. Layered lakes formed by salinity differences are relatively stable. Bradlty( 1963) and Bradlty and Eugster( 1969) firstly explained the formation of oil shale and related lithofacies in the Lvhe Formation according to the layered lake model. According to this model, the lower part of the lake is salt water. The upper part is suitable for the growth of lake organisms such as cyanobacteria, and the lower part has high salinity and strong reduction conditions, which is not suitable for the life of all organisms. Under normal circumstances, the rotten organic sludge at the bottom of the lake is provided by plankton swimming in the upper water body. Excessive reproduction of phytoplankton in spring or summer leads to carbonate precipitation, forming seasonal carbonate stripes. Spring water injection leads to the formation of seasonal clay layer. Later, Desborough( 1978) proposed a biochemical layered lake model to explain the formation of oil shale in the Lvhe Formation. According to the distribution characteristics of oil shale in Songliao basin, the formation of oil shale in the first member of Qingshankou Formation and the second member of Nenjiang Formation is related to layered lakes. Whether this stratification is related to the time of transgression is a question worthy of further discussion.

3. Paleoecological environment

Nenjiang Formation is mainly composed of dark mudstone and oil shale, and carbonate rocks were deposited in Nenjiang period, reflecting a warm and humid climate. At the end of the period, the water body becomes shallow, mainly composed of silt and sandstone, and there are traces of ice crystals in the series, reflecting that the temperature at the end of the period has dropped.

During the sedimentary period, the temperature of Qingshankou Formation was obviously lower than that of Quantou Formation, mainly angiosperms and ferns (a few angiosperms like heat), reflecting the warm and humid environment.

During the sedimentary period of Nenjiang Formation, the temperature was lower than that of Qingshankou Formation, Yao Jia Formation and Quantou Formation. With the expansion of the basin area, the topographic difference becomes smaller, plants gradually adapt to the new environment and flourish, angiosperm pollen is widely distributed, and various plants reach the most prosperous period.

(3) Distribution characteristics of oil shale

Vertical distribution characteristics of 1. oil shale

Oil shale in ore-bearing areas mainly occurs in the first member of Qingshankou Formation, the first member and the second member of Nenjiang Formation. The first member of Qingshankou Formation contains five recoverable oil shale layers, namely K2QN 1-a, K2N2-b, K2N2-c, K2QN 1-d and K2QN 1-e from bottom to top. The thickness of the oil shale layer in this section is 0.75 ~ 5.44m, and the oil content is 3.5655. The first member of Nenjiang Formation contains three recoverable oil shale layers, which are K2N 1-A, K2N 1-B and K2N 1-C from bottom to top. The thickness of oil shale layer in this section is1.97 ~ 4.60m, and the oil content is 3.5 1% ~ 4. The second member of Nenjiang Formation contains three recoverable oil shale layers, numbered K2N2-A, K2N2-B and K2N2-C from bottom to top. The oil shale layer in this section is 0.75 ~ 7.25m thick and the oil content is 3.51%~12.10% (Table 5-65438

Table 5- 12 Vertical Distribution Characteristics of Oil Shale in Nongan Mining Area

2. Plane distribution characteristics of oil shale

Oil shale in the mining area is mainly distributed in five exploration areas: Nong 'an area, Nong 'an periphery, Xiaohelong, Yong 'an and Qingshankou. The distribution characteristics of oil shale in different exploration areas are different, and the plane distribution characteristics of oil shale can be summarized as follows:

(1) Local exploration area and exploration area around Nong 'an.

Oil shale is mainly distributed in the first and second members of Nenjiang Formation, in which the first member of Nenjiang Formation contains two recoverable oil shale layers (K2QN 1-A and K2N 1-B) and the second member of Nenjiang Formation contains two recoverable oil shale layers (K2N2-B and K2N2-C).

(2) Little He Long exploration area and Yong 'an exploration area.

Oil shale is mainly distributed in the second member of Nenjiang Formation and contains recoverable oil shale layer (K2N2-B).

(3) Qingshankou exploration area.

Oil shale is mainly distributed in Qingshankou Formation, including two recoverable oil shale layers (K2QN 1-A and K2N2-B).

The general distribution law of oil shale in the mining area plane is that the higher the oil content of oil shale, the greater the thickness. According to the isogram of oil shale thickness in Qingshankou Formation, the two ore-rich centers are located on the east and west sides of Songyuan, with a maximum thickness of 40m and a distance of 60km. According to the contour map of oil shale thickness in the second member of Nenjiang Formation, the ore-rich center is located 60km west of Songyuan, with the maximum thickness of 12m.

Four. Evaluation of oil shale resources

(1) Analysis of the degree of exploration work

1. Geological exploration work

1959 In March, the Nong 'an Geological Team of Jizhong Brigade of Jilin Geological Bureau submitted the Reserves Calculation Report of Nong 'an Oil Shale Deposit, including the following reports:

(1) Detailed investigation report of oil shale in Nong 'an mining area (reduced to detailed investigation after review);

(2) the general survey report on the periphery of Nong 'an;

(3) the investigation report of Xiaohelong;

(4) Geological survey and exploration report of Qingshankou oil shale mine in Nong 'an County, Jilin Province,1March 96015;

(5) Geological survey report of Baliyingzi oil shale mine in Nong 'an County, Jilin Province,1March 96015;

(6) Detailed geological exploration report of Yong 'an oil shale mine in Nong 'an County, Jilin Province1March 960 15.

2. Degree and accuracy of exploration

In the resource evaluation, the above geological reports are analyzed.

(1) exploration degree and grid.

It is pointed out in the explanatory abstract of the Calculation Report on the Reserves of Nongan Oil Shale Deposit (Volume I) that the oil shale layer belongs to the first category of stability and continuity.

The grid size is 1000× 1000m, and the grade is 2000×2000m.

Class b is 4000× 4000m, and class c is 8000×16000m.

Using this grid, the oil shale reserves in Nong 'an, the periphery of Nong 'an and Xiao He Long are calculated. 1962 Jilin Provincial Mineral Reserves Committee made a resolution on the review and verification of the oil shale report in Nong 'an County, Jilin Province: although the scale of the deposit is large, the quality is not good, the oil content and calorific value are low, and it cannot be developed and utilized by industrial departments at present; In view of the main reasons such as too wide exploration network, improper selection, insufficient research on oil shale quality, and insufficient hydrogeology engineering specialty in the mining area, the following decisions are made on the handling of this report: Article 4 of the report states that it is agreed to reduce the verified reserves as of June 6 1962 to C 1+C 0+C level.

(2) Exploration accuracy.

By counting the area, construction boreholes, exploration lines and grids of each exploration area, the statistical results of reserves reported at all levels show that the agricultural safety zone covers an area of 250km2 with 32 boreholes. Xiaohelong area covers an area of 1 12.5km2, with 13 boreholes; The remaining exploration area covers an area of 1 15 1.5km2, with 23 boreholes.

This report was submitted in March 1959, during the Great Leap Forward. 196 1 on April 9, 2008, the Provincial Reserve Committee wrote in the review resolution of the Oil Shale Deposit Reserve Report in Nong 'an County, Jilin Province, "In the actual exploration work, according to the stability of the deposit, we should master the law of the deposit, creatively apply norms, dilute the exploration grid, speed up the exploration and save a lot of money. The exploration grid is 2,000× 2,000 m (.

Due to the low drilling density, the quality of oil shale can not meet the requirements of the corresponding reserve level. So the survey accuracy is not enough. According to dz/t02 15-2002 Code for Geological Exploration of Coal Peat. All exploration in this area is at the level of pre-investigation and general survey, and the obtained resources are at the level of inference (333). It can't be used as the development basis for the time being, and the economic basic reserves will be obtained after further exploration.

Table 5- 13 Table of Oil Shale and Shale Oil Resources in Nongan Oil Shale Mining Area

(2) Resource evaluation

The evaluation results show that the proven resource reserves of Nong 'an oil shale mining area are 6,543.8+0,555.748 million t, and the recoverable resource reserves of oil shale identification technology are 606.742 million t; The proven reserves of shale oil are 754.99 million tons, the technically recoverable reserves are 294.45 million tons and the recoverable reserves are 220.84 million tons (Table 5- 13).