Through microscopic identification

geochemical analysis and numerical simulation of the intrusions penetrated in the Tazhong-Bachu area

the paper discusses their thermal effect and influences upon the development of carbonate reservoirs.The study indicates that the layered intrusions in the carbonate reservoirs in the area are mainly of hypersthene gabbro and dolerite.The former has labradorite and hyperite as the host minerals and apatite as the accessory mineral

while the later has a host mineral assemblage consisting mainly of clinopyroxene and basic plagioclase.Geochemical analysis shows that the gabbro from Well He-3 and He-4 belongs to alkaline series

with w(SiO

2

)of 44.58%-45.39%

w(K

2

O+Na

2

O) of 3.91%-4.67%

and w(Na

2

O)/w(K

2

O) of 2.16%-4.23%.Its partitioning pattern of REE is of LREE enrichment type

with LaN/YbN ranging from 5.010 to 5.980

and δEu from 0.910 to 1.002

with very weak or even no negative Eu anomaly.The equation of heat conduction was used to calculate temperature profiles adjacent to the thin layered intrusions during the cooling processes.The result points out that these intrusions have limited range of thermal effect

which is closely related to the thickness of intrusions:the thicker

the bigger.