Notes on the trip to North China

1From August to September, 1960, Guan Shicong, Peng Shifu, Yang, Cai Ganzhong, Liu Zhengzeng and others made a comprehensive and systematic field investigation of the North China Basin.

The reasons and background for organizing this survey are as follows: ① New progress has been made in the comprehensive geophysical survey in North China Basin; ② Six benchmark wells have been completed; ③ The oil and gas geological work of oil teams in Henan, Shandong and Hebei provinces has accumulated a batch of new data; (4) The planned North China Petroleum Survey Conference will be held soon, which needs to provide scientific basis for decision-making and deployment.

Journey to North China starts from Zhengzhou, Henan Province, and uses the jeep of Henan Petroleum Team to observe and study the field geological profiles of Jiyuan, Lincheng, Mengyin, Wangcun, Wudishan, Changle, Zhucheng, Weifang and Laiyang in this province. The core drilling geological records of Meng 1, Meng 2, Linzi 2, Boxing 1, Hua 4, Hua 7, Yangsanmu shallow well, etc. 12 wells were consulted. Relevant geophysical survey data mainly refer to the general detailed survey data of earthquakes. In addition to Zhongyuan Petroleum Geophysical Prospecting Team, the detailed investigation data of Hebei Geophysical Prospecting Team in Yangsanmu area of Huanghua were also consulted.

The trip to North China coincided with the difficult period of national natural disasters, and life along the way was quite difficult. Sometimes I used baked sweet potatoes to satisfy my hunger, but I persisted in my geological trip for more than 40 days and gained rich investigation data. Summing up in Qingdao on the eve of National Day. The report "Journey to North China" written by General Manager Guan is a strategic document with far-reaching influence on oil and gas exploration in North China. Its historical value lies in that it is the first-hand data summarized in the oil exploration stage in North China and an important basis for formulating the early oil and gas exploration deployment in North China. In particular, the decision-making proposal focusing on Huang Ji sag was put forward for the first time, which laid a solid foundation for the later Tianjin North China Petroleum Survey and Exploration Conference.

A Journey to North China is divided into five chapters: field debris, core observation, new geophysical data, discussion of several problems and supplementary opinions on prospect evaluation.

"Field Profile" discusses the field geology of eight areas, including Jiyuan Depression in Henan, Lincheng Profile in Hebei, Mengyin Basin in Shandong, Wangcun Profile, Wudishan, Changle Area, Weifang Profile in Zhucheng and Laiyang Basin. Most of the outcrop profiles observed in the field are Mesozoic strata.

There are fossil evidence of Yanchang and Jurassic strata in the western section of Jiyuan sag, Henan Province. Considering that the depression is located in the southwest margin of North China Basin, the tertiary sedimentation should be dominated by marginal facies, while Triassic-Jurassic is expected to generate oil because of its dark shale sedimentation, which can be used as the target layer of the depression.

Lincheng District, Hebei Province. As early as June and July of 1957, I took Wu and Feng Keqiang from Beijing Institute of Geology and conducted stratigraphic research in Yuanshi County, Gaoyi, Lincheng, Neiqiu, Xingtai and other places at the eastern foot of Taihang Mountain. Cretaceous strata were discovered for the first time in Zhu Bi and Weicun, Lincheng, and a large number of gastropods, bivalves and ostracods were collected, which were exposed by exploratory trench and shallow hole drilling.

Stratigraphic sequence: The overlying stratum is Paleogene Liu Jiadong glutenite, and the lower stratum is purplish red shale, grayish green mudstone and sandstone, with an exposed thickness of more than 40m. Contains Sphaerium sp. Bivalves fossils and Darwinula species. Indet。 Darvinula is from Gelmandel. Cyprinidae fish. Ostracoda fossils such as Cyprinidae and Gastropoda fossils such as Planar Bis Sinensis Odnnar, Planar bis cf sinensis Odnner cf Stalliola Gregaria, Static La Gregaria (Brongn). The strata drilled under the profile are mainly gray argillaceous siltstone, and purple argillaceous sandstone can be seen at the bottom, with a thickness of more than 85 meters. It is estimated that you can see the red strata of Shiqianfeng system when drilling 20 meters. Gastropoda and bivalve fossils were identified by Gu Zhihui of Nanjing Institute of Geology and Paleontology, and some of them were considered Cretaceous. Ostracoda fossils were identified by former Soviet Union expert Nikayeva in the Stratigraphic Paleontology Identification Room of the Institute of Geology and Mineralogy of the Ministry of Geology, and according to Hou Hutang's opinion, it is appropriate to set the age of CYPRINIDAE as Cretaceous. Later, the newly discovered stratum was named Lincheng Formation, presumably distributed in the northern depression of North China Basin (later named Qiu Cheng Formation when drilling in Linqing Depression). This achievement was published in Geological Review (1959, No.9), "New Understanding of Cretaceous Strata in Lincheng Area at the East Foot of Taihang Mountain". Lincheng Strata was once listed in North China Strata Table.

After observing the stratigraphic section, Guan Zong and others think that the field impression can be compared with the Qingshan system in Laiyang basin, Shandong Province.

The discovery of Lincheng Group is inseparable from the efforts of female graduate student Wu. She studies hard and never gets tired of studying. Unfortunately, after she left North China, she died of a heart attack in Shanghai.

The last observation point of the "field segment" is Laiyang Basin. Shanqiandian is the best stratigraphic section, and its sequence is mainly composed of Laiyang system, Qingshan system and Wangshi system, and its age is collectively called JBOY3 -K 1-K2. It is striking that there are oil-bearing siltstones and asphalt veins exposed, which generally exist in the upper strata of Laiyang system and volcanic rocks invaded by Qingshan system. Guan Zong thinks: "Laiyang layer located in the axial part has appeared in the northeast of Laiyang. No matter in the narrow sense or in the broad sense, the fault phenomenon is not as complicated as expected. In Zhucheng and Laiyang areas, there is a slow and open anticline uplift. "

JBOY3 -K 1 oil and gas show in Laiyang basin shows that from the perspective of oil and gas geology, if the North Yellow Sea basin located in the northeast can be interrelated in time and space, the oil and gas geological conditions there may be better.

In the observation core of well 12, "core observation" is deeply satisfied with the logging data of well Boxing 1 drilled by Shandong Petroleum Team and well Hua-2, the benchmark well of Shahejie drilled by North China Drilling Brigade of Safety Geological Survey of Ministry of Petroleum. Because the Tertiary sedimentary gray-green phase transition layer has been seen in these two wells, it is expected that deep drilling will encounter dark strata favorable to oil generation environment.

Through the observation of core system and field geological profile, we have a preliminary understanding and view on the correlation and division of Mesozoic and Cenozoic strata in North China.

The report "New Geophysical Data" recorded the gravity and seismic survey data in five areas, including Jiyang Depression.

1. Structural groups in Jiyang Depression

According to the gravity survey results of1:65438+100000, many local gravity anomalies were found in the northern slope, the western slope and the eastern region of Jiyang depression, which showed a nearly east-west zonal distribution. The regional seismic work has confirmed two "secondary structural zones" such as Marco Lin and Dongying and Linyi nose structure. They occupy a favorable geographical position. As shown in the reflection layer, there are huge Mesozoic sediments. In the case that different structural layers in local structures are basically the same, the phenomena such as vertex displacement, poor closure of upper and lower structural layers, and thickening of wing strata indicate the simultaneous formation of structure and deposition, structural inheritance, and fractures and asymmetry in individual structures, which are beneficial to the geological interpretation of structural morphological development process and oil and gas accumulation conditions, and can provide a basis for further deployment of oil exploration.

2. Negative gravity anomaly zone in the north of Huanghua Depression (east of Tianjin)

According to the gravity survey of 65,438+0: 65,438 438+ 10/00000, the northern part of Huanghua Depression, which is connected with Bohai Depression, is a deep depression area, parallel to the east-west trend in the mountainous area of eastern Hebei, with two regional negative anomaly zones and one positive anomaly zone. In the negative anomaly area, there are many positive anomalies of the second derivative of gravity, which should be paid attention to and earthquake investigation and detailed investigation should be carried out immediately.

3. Abnormal display in Kaifeng basin

Kaifeng basin in a broad sense includes Kaifeng sag and Jiyuan sag. In the north of zhongmou county and near Hegang, the electrical uplift is basically consistent with the anomaly of the second derivative of gravity. Two gravity second derivative anomalies, Nanyangzhai and Zhang Miao, in the north of Zhengzhou, also show uplift on the east-west seismic profile, which can explain the reflection interface of Mesozoic strata. This provides favorable conditions for re-evaluating Kaifeng basin.

4. Possible structural zones on the south slope of Huanghua Depression.

On the south slope of Huanghua Depression, except for Yangsanmu, which was confirmed as a structure by detailed seismic investigation, some seismic uplifts such as Koucun, Huanghua, Luqiao, Dacaozhong and Zhuangqiansha Hutong in Yang Er were recently discovered in some seismic profile investigations, which need further detailed investigation and confirmation. However, interestingly, these seismic uplifts are consistent with the positive anomalies of the second derivative of gravity and the residual gravity anomalies. They may form a secondary structural belt with nearly east-west strike, which, like Tongji Yang sag, is a favorable area for oil and gas exploration.

5. Huangchuan sag

It may be the marginal part of Zhoukou depression, where shallow electrical uplift was found, or there may be Cretaceous strata extending from Hefei basin.

"Discussion on Several Issues"

The report concludes, analyzes and summarizes: ① Division and correlation of Cenozoic strata between marginal basins and boreholes in North China Plain; ② Division of tectonic units and Wudi uplift belt; (3) the distribution law and shape of local structure; ④ Mesozoic and Cenozoic igneous activities; ⑤ About the division of plain strata.

The discussion mainly focuses on two aspects: one is the distribution law of local structures, and the other is the obvious arrangement in the Near East, such as Dongying, Marco Lin, Linyi, Yangsanmu, Kongdian and Yang Er Zhuang structures or earthquake uplift. The other is the NNE structure formed in the early Yanshan period, such as Qijiawu structure on the east side of Cangxian uplift and Daxinzhuang structure in Baoding sag. The second is class and association.

Previously, Shandong Petroleum Team had divided the plain strata into layers A, б, B, γ and д. After observation, it is basically agreed, but two points still need to be raised: stratigraphic contact relationship, age and tectonic cycle, which need to be carefully verified, processed, supplemented and modified in further work.

The above stratigraphic sequence was first put forward by Yang et al. of Shandong Petroleum Team, who organized Jia, Yang Chengxian and others to make a comprehensive study of the strata drilled in Jiyang Depression combined with marginal outcrops. Later, it was changed to four groups: A, B, C and D. Group A was officially named as Neogene Huanghua Group and Group B was Paleogene Jiyang Group. The former is equivalent to Minghuazhen Formation and Guantao Formation. The latter is equivalent to Dongying Formation and Shahejie Formation.

Supplementary Opinions on Prospect Assessment is the key conclusion of A Trip to North China. After a heated discussion, the oil and gas exploration situation in North China and the comprehensive geological-geophysical data obtained were deeply studied. The Supplementary Opinions are divided into eight articles:

(1) Laiyang series itself has oil generation and storage properties, and its Fangzi series (including Wutu Formation) also has oil generation properties. In plain areas, areas with gentle stratigraphic folds and less igneous activities, such as individual areas in Laiyang basin, Zhucheng and Huaifang hilly areas, still have oil and gas exploration prospects.

(2) In Jiyang Depression, because we believe that the lower structural layers, including the middle and lower Jurassic and Laiyang System, exist, there are many target layers when drilling in Jiyang Depression. Therefore, B, γ and д are all target layers except б layer itself for oil generation and storage. If it is confirmed that the coal measures of Wutu Formation are equivalent to those of Fangzi Formation, then, as in the lower reaches of Liaohe River, the source rocks of Fuxin, Fangzi and Wutu Formation widely exist in the margin and extend to the center of the plain. Laiyang, Qingshan and loose Wang stratum are all good target beds. It is particularly noteworthy that the discovery of oil-bearing siltstone in Anqiu is a very valuable inspiration.

(3) The fold belt at the edge of the uplift belt has a good structural position. According to the data obtained from shallow drilling, Shahejie in the northern slope of Jiyang Depression, Kongdian and Yanshan in the southern slope of Huanghua Depression are all produced in shallow layers. The strata in these areas are mainly the areas where б layer and γ layer pinch out and uplift, which is beneficial to oil and gas migration and storage. Therefore, the marginal areas along Huang Ji sag and Wudi uplift, including east of Tianjin, south of Huanghua and east of Guangrao, are the most promising areas, especially Koucun, Fangzhuang and Dongying in Guangrao near Huanghua. The gravity display is basically consistent with the seismic data. These structures are located in the saddle of two gravity depressions (negative anomalies), which are most suitable for oil and gas migration and accumulation and should be listed as key breakthroughs first.

(4) Considering the new subsidence, the Pliocene stratum in the eastern part of Huanghua Depression is thickened, and drilling also proves that the lithology of layer A is thinner to the east and north, which means more sediments representing the deep-water reduction environment, which is beneficial to oil generation. Therefore, it is particularly noteworthy that the area east of Tianjin is connected with the Bohai deep depression. The seismic profile from Tianjin to Tanggu shows that layer A tends to thicken eastward, and layer A itself may constitute the conditions for oil and gas generation and storage.

(5) Kaifeng basin should be reevaluated. NeoTriassic extended sandstone does exist in Jiyuan area of Kaifeng basin, which may be the main oil reservoir. However, the occurrence of Middle and Lower Jurassic in Jiyuan Basin is good. At first, it was considered that the Yanchang sandstone in Mengxian borehole may still be Jurassic with asphalt veinlets. According to the results of electrical survey, there are many NW-trending uplifts in Jiyuan basin, which may be the extension zones of several anticlines in the western mountainous area of the basin. In the east of Wuqing Uplift and along the middle of Kaifeng Depression, not only the second derivative anomaly of gravity was found, but also a uplift was shown on the east-west seismic profile from Xingyang to Zhang Miao. The seismic reflection also indicated that there was Mesozoic in Kaifeng Depression. There may be oil-bearing strata, oil-bearing structures or anomalies in Kaifeng basin, which is inseparable from the whole North China Plain in terms of sedimentary environment and properties. Therefore, we should attach great importance to Kaifeng basin and strengthen geophysical survey again.

(6) Huangchuan Basin is small in scope, but there are thick Mesozoic strata in its southern margin, which are obviously related to the oil-bearing Mesozoic in Hefei area. Therefore, it is necessary to consider geophysical prospecting and drilling survey in Huangchuan basin in order to make a long-term evaluation of Huangchuan itself and Zhoukou basin in the north.

(7) In the past, the geological interpretation that the western margin of Boye Basin, especially Wuqing and Baoding Depression, belonged to marginal facies was not enough. Along the eastern foot of Taihang Mountain, Xishan Basin, Lingshan area, etc. Mesozoic and Cenozoic sedimentary thickness is large, lithologic conditions are good, and many secondary depressions and bulges in Boye sag are also arranged in order. Therefore, the possibility of oil-bearing in Boye and Wuqing Sags cannot be ignored.

(8) In addition to Tianjin, middle-deep and shallow natural gas have been discovered in Shunyi and Zhuozhou in the suburbs of Beijing, so it should be considered that their appearance is not accidental. Studying the phase transition and the distribution of б layer in North China (Pliocene A layer) is the basis for finding tertiary natural gas in North China Plain. Therefore, the Quaternary natural gas was recently discovered in the old channel area of the Yellow River in Shandong Province, with abundant flow, which also indicates that shallow natural gas reservoirs may be discovered in the vast ancient Yellow River basin area.

After the writing of Journey to North China, it aroused strong repercussions among the main technicians in the three provinces, and the conclusions put forward were highly theoretical and targeted, which was recognized as the top priority of oil and gas exploration and evaluation in North China, especially the following two issues:

1. Select North China as the breakthrough point.

After five years of comprehensive geological and geophysical investigation, the problem of constituency should be raised as soon as possible in order to narrow the encirclement and find a breakthrough. Through on-the-spot investigation and data analysis, it is accurately put forward that "the areas east of Tianjin, south of Huanghua and east of Guangrao are the most promising areas, which are most suitable for oil and gas accumulation and should be listed as the leading areas for key breakthroughs." This is a breakthrough in the early oil and gas exploration in North China from theory to practice, the key to solving the oil and gas mystery in North China, and it can be called a monument in the history of oil and gas exploration in North China.

2. Re-evaluate Kaifeng Depression

Before 1960, the Ministry of Petroleum Industry had drilled Well Hua 2 in South Shenzhen-Hong Kong of Kaifeng Depression and Well Hua 3 (Fangerzhuang, guanxian, Shandong Province), Well Hua 4 (Tangyi, Liaocheng, Shandong Province), Well Hua 6 (Tangyi, Liaocheng) and Well Hua 5 (Tongxudige, Henan Province) in the northern part of Linqing Depression. No oil and gas was found in Mesozoic and Cenozoic, which had a great influence on the evaluation of Kaifeng sag. However, we share the same view with the comrades in the North China Petroleum Exploration Office, and both believe that we can't draw a negative conclusion under the condition of extremely low exploration degree. General Guan stressed in his report: "There may be oil-bearing strata or structural anomalies in Kaifeng Basin, which are inseparable from the whole North China Plain in terms of sedimentary environment and nature. Therefore, Kaifeng Basin should be highly appraised, and the general survey and detailed investigation of geophysical exploration and drilling should be strengthened again. "

The report "Journey to North China" was written by the general manager of Qingdao Guan. Qingdao is a beautiful coastal city with blue sea and blue sky, red tiles and green trees, and is known as "Switzerland of the East". We live in the municipal guest house near the trestle bridge, so we should relax the tense and tired travel life in recent months and then walk along the seaside. The waves aroused our appetite for seafood. General Guan gladly invited us to a restaurant to drink Tsingtao beer, and the faint scent of hops in the cup made everyone feel quite touched. If only North China could take this risk! At this time, General Guan talked about the next exploration and deployment plan. He looked at the waves in Jiaozhou Bay and said that North China would drill around Bohai Bay. He believes that Jiyang, Huanghua, Bohai and Xialiaohe Depression belong to the ancient Bohai Basin, which should be the sedimentary center of North China and have good oil and gas prospects.

As the sun sets, the sea and sky are shining, and the scenery is charming. We are full of alcohol and picking up shells on the beach. Lucky birds and seagulls seem to bless us!

Shortly after the trip to North China, it was learned that a set of gray, gray-green mudstone mixed with white siltstone was discovered underground in Hua 7, which contained a large number of paleontological fossils and was rich in organic matter, and was confirmed as a good source rock. The seismic profile shows that this layer is widely distributed, indicating that Jiyang depression has very favorable oil-forming conditions and exploration prospects. This is an important achievement made by the North China Petroleum Exploration Office since the Huazihao benchmark well, which basically confirms that the North China Basin will be a large oil and gas-bearing basin. Later, Shuai Defu named this Paleogene "Shahejie Formation", which has been in use ever since, and contributed to the formal establishment of tertiary stratigraphic sequence in North China.

198565438+In February, I mentioned the history of Journey to North China in the Early Oil Survey in North China Basin published in Volume 6, Issue 4 of Petroleum and Natural Gas Geology. However, for some reasons, the report has never been published publicly, but it has played a role in practical work. The disclosure of details after 37 years can provide important and precious historical materials for the study of early oil and gas exploration and discovery in North China (the original report of A Journey to North China was poorly printed on paper, and some of its handwriting was illegible, but it was finally saved by me after I printed and copied it with laser).