| Lujiapu Sag is one of sags in Mesozoic sags surrounding Liaohe, which the exploration was made earlier and where exploration success was also gotten earlier. In this research, the interesting area located in Geli oil field and its suthern area, which was on the east of Jiaolige seg, Lujiapu sag, Kailu Basin. The exploration and development of this area was blocked because of the blanked block in the seismic data, which was developed with the influence of water storage reservoir and low quality of seismic data. So, a new 3D seismic data was gathered for further interpretation to (1) clarify the fault distribution and the structure, (2)characterize the distribution of favorable reservoirs with the research of sedimentary system, and then (3) make a guide for the development and drilling.This research was based on the cycle theory of sequence stratigraphy and reference-layer-based strata correlation theory. Strata correlation and accurate calibration were made with drilling, logging and production data in the strata of lower Jiufotang group, upper Jiufotang group, Shahai group and Fuxin group.It deposited lake-sedimentary systems. The facies of neritic fan, fan delta, lacustrine sedimentation and offshore were all developed. It deposited fan delta and lake sediment in strata of early Jiufotang; in the late Jiufotang period, the lake expended and the sediment-supply was lacked, so retrogradation developed and it deposited fan-delta and lacustrine sedimentation. Although, the area of the lake in Shahai period was the similar with that of late Jiufotang, the level dropped significantly, so sedimentation of shore and shallow lake were dominated in the fan-delta and lacustrine sedimentation. In the Fuxin period, with the attenuation of the tectonic activity, there were a further basin-filling and lake-atrophy, fan-delta and shore sedimentation developed on the basin edge while deposition of shallow lake developed in the center of the seg.After bottom interpretation of the above groups, the fault and structure were clarified. The faults were classified in three according to their affection, scale, period and active time. Seven new favorable traps were found in two groups. Four tectonic periods were classified including disproportionate rift period, slow-stable rift period, whole-stable depression period and bi-faulted depression period. The reservoir distribution of lower Fuxin group, Shahai group and upper Jiufotang group was characterized with the seismic inversion result. In upper Jiufotang, the max sand thickness was 354.0m which was located around well Jiao25 and Jiao 18; the sandbody was northward thinner and the thickness was between 50.0m and 200.0m. Reservoir developed worse in Shahai group; the reservoir in the bottom developed better than that of the middle and upper parts. The sand bodies of this formation developed in the south and west. In lower Fuxin group, the max sand thickness was 48.0m and 47.0m which separately located around well Jiao4, Jiao 25 and Jiao50-54; the sandbody thickness was between 0m and 48.0m.In this research, it is concluded that there are three types of reservoirs including fault- anticline reservoir, fault-nose structure reservoir and fault block reservoir. Fault-anticline reservoir was the dominated. The reservoirs are controlled by both structure and lithology.Based on the theory of Sedimentology, Petroleum Geology, Reservoir Geology, Sequence Stratigraphy and land-basin hydrocarbon gathering theory, comprehensive geological evaluation was made with the result of researches including seismic interpretation, reservoir predication and reservoir characterization. In this research, the research area was classified into three favorable belts and 4 new wells were suggested.
|
PDF Full Text Request