Evaluation Of Volcanic Reservoir In Gu 16～(th) Well Area, Kramay Oil-field

The Gu 16th well area lies between Baijiantan area and Baikouquan town, Kramay city, in the middle of Kramay-Wuer river' great overthrust fault zone ( or Kramay great fault ) that is in the northwest of Junggar basin, and in the south of Baijiantan-Baikouquan which lies between Baijiantan fault and north Baijiantan-Baikouquan fault in textural. It is a frontal block felt that belongs to Kramay great overthrust nappe structure. The Carboniferous volcanic reservoir is very rich in which rich hydrocarbon reservoir is found. But structures are involute, distribution of lithological character has no rule and volcanic reservoir has heterogeneous feature, so knowledge to volcanic reservoir is low and the exploitation work for this reservoir faces great difficulty. This paper explains structure, lithology, and evaluation and comparison of stratum firstly by using drilling material, core material, and emphatically logging material, then appraises and explains fractures of the volcanic rock, and finally appraises the fractures of researched area.Then the following some knowledge is given:1 ) Structures in this area are a part of front of nappe structure and controlled mainly by nappe structure. Volcanic rock layer inclines to northwest and obliquity is big.2 ) Volcanic lithological character is involute. Owing to the influence of volcanic formation fashion and structure, distribution of lithology has obvious rule either in portrait or in landscape. But log response feature has zonation to some extent. There are four log fades zones in portrait which were developed under the influence of deflation after structural movement and are not real zones on the mean of lithology.3 ) Fractures in the volcanic reservoir are rich and mainly middle and low obliquity fractures. Of them reticulated fractures have the best density which reaches 10-15 strip/meter and 12.9 strip/meter averagely. Oblique fractures have the second density and its average of this area reaches 3.11 strip/meter. Fracture porosity calculated by log material is between percent 0.01 and percent 0.08 and fracture width is between 0.01 um and 35 urn. Owing to some fractures are packed fully or partly, validity of fractures is confined to great extent. Direction of modem earth stress in researched area is about 1000. And natural fractures that extended to this direction perhaps splay to some extent, as is useful to migration of hydrocarbon.4 ) The type of Carboniferous reservoir space is mainly intragranular solutional void, micro-fracture, fracture, matrix solutional void. Of them fracture and matrix solutional void are the mam reservoir pore space.5 ) There are two reservoir models, i.e fracture model that fractures connect each otherdirectly and pore-fracture model that fractures connect each other indirectly.6 ) Volcanic reservoir is a multiple medium reservoir that constitutes of fractures and matrix pores. Carboniferous reservoir has two reservoir models, i.e low porosity fracture model and pore-fracture model.