【摘要】 在塔里木盆地奥陶系海相碳酸盐岩中识别出准同生岩溶、风化壳岩溶、埋藏岩溶3种不同类型的古岩溶作用。根据地质、录井、钻井、地球物理等响应特征,分别总结了它们各自的主要识别标志。粒内溶孔、铸模孔和粒间溶孔等组构选择型溶孔的发育,非组构选择型溶孔、小型溶洞、溶沟和溶缝及其渗流粉砂充填物的出现,大气淡水胶结物的产出等是准同生岩溶的主要识别标志;风化壳岩溶作用主要的识别标志包括:风化剥蚀及其伴生的风化残积层,高角度的溶沟、溶缝及落水洞,大小不等的各种溶蚀孔洞及其相应的充填物,充填物具有大气水参与的地球化学特征,钻井过程中的钻具放空以及泥浆的大量漏失,高自然伽马和低电阻的测井响应特征,相对低速的地震反射特征;埋藏岩溶作用一般可以根据地层水对原有孔洞缝的增溶并被油气充注的特征加以识别。指出准同生岩溶作用控制了早期碳酸盐岩储层的形成与分布,风化壳岩溶作用是储层形成的关键作用,埋藏岩溶作用则是储层优化改造的关键因素之一。更多还原

【Abstract】 Three types of palaeokarst can be recognized in Ordovician non-marine carbonate in Tarim Basin,which are syndepositional rock-dissolution,weathering karstification and buried rock-dissolution.Their main recognizable indicators are summed up by analyzing the responsive characteristics in the aspects of the geology,well logging,drilling and geophysics.The recognizable indicators of syndepositional rock-dissolution include abundant texture-optimal dissolved-pores,such as the intra-grain,mold and inter-grain dissolved-pores,and non-texture-optimized dissolved-pores,small-scale dissolved-caves,dissolved channels,dissolved-fissures,as well as vadose silts and meteoric freshwater cements.The recognizable indicators of weathering karstification include the Ordovician carbonate weathering out and residue on a regional unconformity,high-angle dissolved channels,dissolved fissures,sinkhole,dissolved pores and caves with different scale and the fillings,the carbonate fillings in the dissolved pores and caves are of the geochemical characteristics that meteoric freshwater is of,the drilling break leakage occures,the well logging response is characteried by high combination gamma ray neutron value and low electrical resistivity value,as well as the low-velocity seismic response characteristics are dominant.The buried rock-dissolution can be recognized by further original pore and cave dissolution and infilling by oil and gas.It is indicated that early development and distribution of carbonate reservoir are controlled by the syndepositional rock-dissolution,the weathering karstification is the key to the formation of carbonate reservoir,the buried rock-dissolution is one of key factors of optimal reworking of carbonate reservoir.更多还原