| The tidal area of eastern Changdi is located in the northeast of Zhan Hua sag. The drilling result shows that there are 5 sets oil-bearing series in the research area(Guangtao Formation, Dongying Formation, Member 1 of Shahejie Formation, Member 3 of Shahejie Formation, Mesozoinc Erathem). The ground condition of shallow beaches and the complicated geological situation of this area has limited the exploration, which lead to a main research focus on the fracture area in the west of Changdi and the grade of exploration was represented by the greater height in the west than the east, even in the northeast research area without drilling. The current main problems in the process of exploration in the research area are: the study of sediment filling history cannot be a good combination of tectonic evolution, the oil and gas are hard to be preserved in the lower part of Guantao Formation which makes it difficult for seeking out the effective traps, and the upper part of the Guantao Formationa and Member 1 of Shahejie Formation reservoir is thin with fast changes of lithology which makes it difficult to be described. Therefore, it results to unclear exploration targets with consequence of many no oil and gas wells and low production wells.To the issues above, the thesis, under the theoretical guidance of sequence stratigraphy, seismic sedimentology, petroleum geology and other theory, does the research on the prediction about the structural characteristics, sequence stratigraphic classification, sedimentary facies and seismic reservoir of the tidal area of eastern Changdi by making the full use of the well point data and seismic data. Below are the main results:1. The thesis completed the calibration and interpretation of horizon and three-dimensional fault interpretation, and reveals a new recognition to the fracture structure and tectonic evolution in the research area. 3-D coherent data volume, which is the most visualized fault interpretation, was also achieved by detailed processing. The coherence technology highlights the non-similarity relation between neighboring seismic trace which identifies fault and other geological anomaly with more effectiveness and accuracy. The major fault in Changdi area controls the structural characteristics which leads to a tectonic framework with south high and north low, east high and west low. Fault activities are the key controlling factor for forming up traps and it has the characteristic of the episodic activities by ‘Jiyang Movement' and ‘Dongying Movement'. Tectonic evolution affected by the tectonic movement is divided into fold uplife stage, extensional rift stage and steady subsidence stage, including extension rift stage which is further divided into from Member 3 of Shahejie to Member 2 of Shahejie?episodic and from Member 1 of Shahejie to Dongying?episodic. Changdi fault zone was overlapped faults created by two stages of tectonic movement. The formation of the two unconformity interfaces in Changdi area had close relationship with the episodic activities. Several unconformity interfaces were formed up in the sedimentary strata which showed the importance of multicycle fault depression in the Cenozoic tectonic evolution.The period from the end of the sedimentary in Dongying to the beginning of Guantao was the basic transition stage when en-echelon faults were being developed. Tectonic movement of the imbalance caused that structural high point has the characteristic of southward movement from the deep structural layer to the shallow structural layes, and Changdi rise plunging towards north.2. According to the theory of sequence stratigraphy, the thesis establishes the sequence stratigraphic framework of Shahejie Formation, Dongying Formation and Guantao Formation. It also studies separated layer of logging in the research area by using frequency spectrum analysis, the instantaneous amplitude attribute analysis, log section analysis of strata division. The adjusting scheme is proposed to the problem of the stratigraphic division of the Member 1, 2, 3 of Dongying Formation, ultimately getting sound data of strata division. Member 1+2 of Dongying Formation is not a set of second or third-order sequences, but a highstand system tract in third-order sequence. 3 second order sequences( ? ~ ?) and 5 third order sequences(SQ1~SQ5) are distinguished from the Paleogene Shahejie Formation to the Neogene Guantao Formation in the research area.?sequence is divided into 2 third order sequences, an equivalent of Member 3 of Shahejie Formation(SQ1) and Member 2 of Shahejie Formation(SQ2).?sequence is divided into 1 third order sequences, equivalent of Member 1of Shahejie Formation plus Dongying Formation(SQ3).? sequence is divided into 2 third order sequences, an equivalent of the lower part of Guantao Formation(SQ4) and the upper part of Guantao Formation(SQ5).3. Based on a great deal of core data, logging and well testing within the sequence stratigraphic framework, this thesis analyzed single well sedimentary facies. And on this basis to analyze the characteristics of sedimentary evolution in the research area for thicker strata using a split evenly slices of along the layer, and extract the sensitive seismic attributes. The development of Member 3 of Shahejie Formation is deposit fan nearshore beneath the water which is remanent. The top of the fan is also with heavy erosion. The stratum of Member 2 of Shahejie Formation is mostly missing in the research area, but is still developing the fan deposit nearshore in the west of this area. The stratum of Member 1 of Shahejie Formation, which remains stable, is developing bio bar deposit. Member 3 of Dongying Formation preludes the main body of fan delta deposit entering into the research area, it develops fine sediment at the front side for fan delta deposit, such as sandbank and turbidity deposit, etc. Member 2 of Dongying Formation is composed mainly of the front side of fan delta deposit. Member 1 of Dongying Formation is mainly composed of the plain deposit of the fan delta deposit. The lower part of Guantao Formation develops sandy wandering river deposit which is not braided stream deposit recognized traditionally. The bottom of the upper part of Guantao Formation contains lots of thicker sandstones which obviously do not belong to meandering stream deposit, so this thesis indicates the the research area develops the fan delta deposit in a small scale.4. Through comparing the distrubtion characteristics of sterane to terpane and the analysis to the tectonic evolution, this thesis indicates the oil and gas from Z303 to Z47 oil block is derived from Wuhaozhuang subsag. There are two main properties for the oil and gas distribution by understanding the volumn in the wells explored, that the oil and gas is distributed by the pattern of one side-two long-slope and the burial depth of the rich layer of oil and gas is with a trend of upraising from south to north.5. In the research area with the positive structural belt, the volumn of the oil and gas is controlled by the favorable reservoir caprock and fault activity. The favorable place for accumulating oil and gas is the sand channel body in the mid-fan nearshore of Member 3 and 2 of Shahejie Formation. The thicker bank bars developed in Member 1 of Shahejie Formation formulates effective reservoirs which develops the structural oil pool. The block sandstones in the lower stage of the lower part of Guantao Formation act as the transfer layer for the favorable oil and gas network. Therefore, it vertically stacks with the river bank along the edge and mid-area of the river. The top of block sandstones also develops well on faults which serves as a good spot for great traps. The lower area of the upper part of Guantao Formation develops fan delta deposit in small scales which can formulate favorable traps in the proper structural area.6. The thesis predicts the regularities of distribution of the sand group in Guantao Formation through well constrained seismic. It also searches for the favorable development area of reservoir according to the previously found oil pool features. The prediction to the favorable target area will be done by looking for the high point of structure in the moving path of oil and gas in the reservoir of Shahejie Formation and Dongying Formation. Therefore, it is suggested to implement five wells.The thesis has gained two new creative recognition through above research:1. Research on the log layering using methodologies of Analysis of logging curve spectrum properties, instantaneous amplitude attribute and log bisect. Redistrict the boundaries of Member 3, 2 and 1 in Dongying Formation, as well as the top boundary.2. Through the analysis of sedimentary facies, the thesis identifies the sandy wandering river deposition in the lower part of Guantao Formation excluding the brained river deposition; categorizes the thicker sand layer at the bottom of the upper part of Guantao Formation into fan delta deposit in small scales; also proposes that there should be a hypothesis on strata succession interface with higher level between upper and lower part of Guantao Formation, based on the huge difference between the braided river near source sedimentary system in the upper part and the meandering river sedimentary system of remote source in the lower part of Guantao Formation, thus to be divided into three layers of strata succession interface. |
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