Comprehensive Research On The Formation Condition Of Volcanic Hydrocarbon Reservoir In Malang Depression In Santanghu Basin

Igneous hydrocarbon reservoir is the type of unconventional hydrocarbon reservoir whose reservoir body is mainly composed of igneous rock which possesses of reservoir space, fractured volcanic hydrocarbon reservoirs are characteristics of varied of mineral compositions and structure types, strong heterogeneity of reservoir space and regularties of hydrocarbon bearing are difficult to identify. further study the formation conditions and distribution laws of volcanic hydrocarbon reservoir if of great theoretical and practical significance.This paper starts with the evolution of regional geological and characteristic of volcanic rocks. By using outcrop, drilling, logging, well logging and seismic data,and combined with the distribution of the source rock in volcanic hydrocarbon reservoir. We take fractured volcanic hydrocarbon reservoir in malang depression as research object and do comprehensive research on petrology, petrography, hydrocarbon source rock and fractured volcanic hydrocarbon reservoir. We discusses the formation rules and controlling factors of volcanic hydrocarbon reservoir. Besides,we indicates the direction of exploration Conclusions are as follows.(1)The lithology of volcanic reservoir in malang depression is determined to be basalts, trachyandesites, andesite and basalt-andesite et.al.(2) The lithofacies of volcanic rocks are explosive facies, effusive facies,volcano-sedimentary facies and volcanic channel facies Volcanic mechanisms in malang depression are central type, fractured eruptive and fractured overflow type. On the basis of the features of volcanic rock lithologic association, we create three compound phases which are relative to six types of seismic facies.(3) Volcanic reservoir can be divided into insider type reservoir developed in the inside of volcanic rock body, weathering type reservoir developed on the top of volcanic rock body and fractured reservoir due to tectonic stress. Volcanic reservoir space is mainly composed of dissolution fractures, structural fractures, weathering fractures and leaching matrix pore, intergranular pore, dissolved pore, stomata and amygdale internal pore and so on.(4) Volcanic hydrocarbon reservoirs have weathering-leaching type and fractured-porous type,and its main controlling factors are tectonic conditions(Aged nose uplift), fractured translocating systems, development degree of reservoir space, hydrocarbon source rock conditions, volcanic mechanism types.features of lithology and lithofacies and sealing conditions.(5) Seismic coherence cube techniques and fracture detection are used to indicate the volcanic fractures in malang depression.The indicated the rang of volcanic favorable lithofacies belt is assess to aged nose uplift. The integrated three-dimensional distribution map of favorable volcanic reservoir in malang depression is plotted.(6)We point out the feature of multiple sources and multiple kitchens and multiple series of strata in volcanic reservoir in malang depression, tectonic conditions (Aged nose uplift), fractured translocating systems development degree of reservoir space, hydrocarbon source rock conditions, volcanic mechanism types with its lithology and lithofacies features and sealing conditions are considered to the key factors of the reservoir forming of volcanic hydrocarbon reservoir.