Abstract:

Volcanic rocks of the Yingcheng Formation are main reservoirs in Xingcheng gas field. Geochemical and petrological research shows that neutral and acid volcanic rock is the major type of volcanic rocks in the Yingcheng Formation. Core and thin section study reveals that gas pore and devitrification pore are the main accumulating spaces in lava as well as intergranular pore, intragranular pore and dissolved pore in volcaniclastic rock. Core analyses show low porosity and permeability characteristics of the volcanic reservoirs. The control factors of volcanic reservoirs are analyzed based on the data of core and thin section. Types of volcanic rocks and volcanic facies control the development of original pores, and diagenesis modifies original pores and fissures, and tectonic action leads to the formation of structural fissure, which contribute a lot to effective drainage of volcanic reservoirs. It is concluded that favorable volcanic facies near the volcanic crater are the pay zones in gas exploration and development.

Key words: Xingcheng gas field, volcanic reservoir, reservoir space, control factor, volcanic facies, diagenesis, tectonic action