库车坳陷古近系盐底卡层技术研究与应用

库车坳陷主体广泛分布古近系膏盐岩,最厚达4000m.盐层底部沉积模式多样,无统一综合对比性标志;同时由于南天山隆升产生垂向剪切与盆山挤压运动,膏盐层塑性复杂变形,导致盐底精确卡层困难.结合欠压实理论总结出盐间泥岩与盐底泥岩的区别,利用120余口井实钻资料,结合盐下沉积序列、底砂岩岩性序列、白垩系残余厚度等证据,刻画了研...

Research and application of the base salt rock discrimination of the Paleogene in Kuqa Depression

The Paleogene gypsum-salt rock is extensively developed in the main part of Kuqa Depression,with a maximum thickness of up to 4000 m.There are diverse deposition patters of the base salt rock but a lack of the unified marker bed.Moreover,influenced by the vertical shear stress and orogenic compression during the uplift of the south Tien Shan Mountains,the gypsum-salt rock experienced intensive plastic creeps,and the complex lithologic association brought difficulties in accurately discriminating the base salt rock.Based on the undercompaction theory,the differences between inter-salt mudstone and base-salt mudstone are summarized.Then the sedimentary pattern of multiple salt lakes is characterized and the zonal sedimentary sequences are identified of the subsalt sequence by using drilling data from 120 wells,as well as the subsalt sedimentary sequence,lithologic association of basal sandstone and residual thickness of the Cretaceous;The cuttings,mud logging and wireline logging data enable to determine the lithologic associations at the base salt layer and establish a lithologic association plate for different zones;The differences between inter-salt mudstone and base-salt mudstone are compared and an on-site identification standard is set up based on the lithology,mineral composition,element composition,wireline logging and seismic facies characteristics;A series of quantitative indexes for discriminating the base salt mudstone are precisely established in various zones by using sedimentary sequences,drilling,mud logging,wireline longing and element geochemistry data;Finally,the micro-drilling time,XRF logging,and pilot well data are applied to develop an applicable discrimination method and field operation scheme by integrated geology and engineering.The technology ensures the safe and rapid completion of 31 exploration wells,which provides solid technical supports for building the largest production base of ultra-deep natural gas with a production capacity of 30 billion cubic meters.