Prediction Of Volcanic Reservior In The Changling Graben-depression

Late hydrocarbon exploration of the Changling graben-depression in Southern Songliao has resulted in a great breakthrough.. The production well named Yaoshen-1 outputed gas of 200 thousand cubic meters a day in the reservoir of Yingcheng Formation. Identification different volcanic rock is difficult, and the causes are included of the complex lithology and lithofacies of volcanic rock. The volcanic rock usually is inclined with the continental-margin clastic rock and mud rock. In view of the problems above, a comprehensive method has been used for research, based on volcanic rock lithology, facieology, lithochemistry, petroleum geology and reservoir geology. The seismic, geophysical logging, magnetic, coring, assay and outcrop datum are helpful. The content as follow: classification, characteristics, lithofacies, stage, cycle, distribution, controlling factors of volcanic rock, prediction for favorable reservoirs of different types and the main factors controlling hydrocarbon accumulation. The conclusion as follow:(1) In the Changling graben-depression, there are six cycles of volcanic eruption, and the main two are Huoshiling and Yingcheng.(2) With seismic and magnetic evidences, large volcanic craters and volcanic conduits usually arranged along the faults continuously. The volcanic craters in Yingcheng Formation transported toward the northern. And the thickness of volcanic rock become accreted along three faults, one of which form northwest to southeast, and the other two from south to north.(3) The volcanic rock with higher resistance, lower acoustic-time and higher or lower gamma-ray contrasting with clastic rock.(4) The basalt, andesite and liparite are expressed with high seismic amplitude, the two former are basic, and the latter is acidic.(5) Composition and boundary of Changling graben-depression are researched, and the effect of fault with volcanic rock and sedimentary rock also is analyzed. The Yingcheng Formation has been divided into four seismic zone, by the attributes such as seismic amplitude and waveform.(6) In the Yingcheng Formation, the porosity and the permeability of volcanic reservoirs are tested, and divided into four levels.