铁山南气田长兴生物礁气藏的储层地质特征研究

GEOLOGIC CHARACTERISTICS OF CHANGXIN ORGANIC REEF RESERVOIRS,TIESHANNAN GAS FIELD

铁山南气田长兴气藏经4次容积法储量复核差异较大。为了搞清造成这种差异的主要原因,有针对性地采取措施来提高气藏的开发效益。本次研究是在钻井、试油及测井资料综合分析的基础上,确定生物礁的有效分布范围求得储量。该储量值经压降法与数模法的验证具有较高的可信度。同时也说明对该气藏储层地质特征的剖析,是符合气藏实际的。文中认为,造成储量复核差异的主要原因,是对长兴生物礁的地质储层展布特征认识不同造成的,气藏生物礁的储层展布主要受断层及岩性因素的控制。储层孔隙以晶间孔和粒间溶孔为主,物性具中低孔、中低渗特征,储层构造缝发育,属裂缝—孔隙型储层,且可划分为Ⅳ种类型。气藏Ⅱ类、Ⅲ类储层在较发育裂缝的连通作用下,获得了高产。

For Changxin gas reservoir' reserves,we have carried out four calculations with volumetric method.However,there exists a big difference.Some measures have been taken to improve the reservoir's development benefit in order to make clear the reason resulted in the big difference.In this paper,we determined the effective distribution of reef to obtain the reserves based on the comprehensive analysis of drilling,well testing and logging data.The reserves are approximately identical with the reserves obtained from both drawdown testing and numerical simulation.Meanwhile,it is indicated that the analysis of reservoir's geologic characteristics is coincident with the facts. The main reason for the big difference is due to the different understanding for the reservoir distribution,which was primarily controlled by fault and lithlogy.With intercrystalline pore and intergranular dissolved pore as the soul,Changxin organic reef reservoir is of fractured-porous type.And its petrophyscial property is characterized by middle-low porosity and permeability and tectonic fissure are developed.The reservoir is classified into four types,among which type II and type III have obtained high productivity because of connectivity of well-developed fractures.