Reservoir Prediction For Cenozoic & Mesozoic Erathem In South-western Part Of Jianghan Basin

Based on the theory of modern sedimentary , tectonics , classical sequence stratigraphy and successful experiences of Oil & Gas exploration in the structural slope-break zone ,this paper goes deep into studying completely sedimentary system and model in south-western part of JiangLing Basin, indicates the distribution of some sandy bodies and purposes pool-forming mechanism of fault block zone . There are some conclusions and views as follows. (1) In south-western part of JiangLing Basin, tectonic evolution controlled the 2-order sequences, and affected by tectonic, climate and sedimentary supplements, changes of the base level cycle control the 3-order sequences. It is the first time to found up the sequence stratigraphic framework in studying area and deposit pattern based on the fault subsidence lacustrine basin. This paper put forward that Cai xue-Fu xingchang fault block zone ,which was called broom-like fault zone, cut by NNE fault , NW fault and their derived one , form a oil-rich fault block zone . (2) In this paper, the author illustrated the depositional system and model in studying area, and distinguished 14 kinds of lithofacies and 3 kinds of depositional system which were the alluvial fan and fluvial-delta system, turbidity fan- half deep lacustrine system. It is the first time to expound the genetic pattern and distributing rule of the fault block zone. In this area, the sediment supplements are from nearly north, the alluvial fan-braided fluvial sandy bodies distribute around the Cai xue fault block; the meandering stream-delta sandy bodies are developed in Fu xingchang area; the turbidity fan bodies mainly distribute up the western Xie fengqiao area. (3) The fault block zone developed fault-lithological pool whose hydrocarbon source belong to EX1—ES2 in the Mei Guiqiao depression. The pool , called other-fountain side-direction ladder-shape one,mean that by Xie Fengqiao fault, the cruade oil was migrated to the channel belt sandstones in Fu Xingchang fault block, and then formed New-Generation-Old-Storage reservoirs. (4) With the synthetic sequence analysis of well logging data and core data ,the highly resolution sequence architecture is build in Fu Xingchang fault block in Jiang Ling depression. They are divided into six middle-term cycles and seventeen short-term cycles in Cretaceous Yu Yang formation. Based on the analysis of sedimentary microfacies, this paper summarized the sedimentary evolvement and distribution pattern during the periods of each base level cycle. (5) This paper goes research to some technical problem about isochronal sequence stratigraphy ,the prediction of the subtle reservoirs etc, and then based on the high resolution sequence stratigraphy microfacies correlation and armed with advanced geophysical interpretation and processing , preliminarily establishes a set of reservoir prediction techniques .Using the Neural network wave shape classification to qualitatily identify sandy bodies shape and distribution, adopting the constrained sparse pulse impedence inversion combined with the multiplex seismic parameter attribute extraction and analysis ,such as absorption coefficient, instantaneous frequency, and reflecting telescope, to trace and forcast reservoirs, a north-eastern reservoir belt of K2y3 was predicted in the middle of Fu Xingchang No.1 fault block,and three beneficial reservoirs of K2y4 were predicted in north ,middle,and south-eastern studying area. Through all those work, the exploration was preferablyguided,and the larger economic benefit and social benefit was acquired.