New Technologies in Geosteering on Example of South Tambey Gas-Condensate Field

摘要

Severe climatic conditions, backwardness of infrastructure and becoming complicated geological structures – here what development of new fields in Russia now faces. Rise in operational price demands from service companies intensification of efforts in obtaining additional data at log interpretation measuring in real time during drilling. One of rather new directions in geology is geosteering-direction which has received a powerful push with the appearance of new LWD tools allowing us to measure and analyze spatial three-dimensional data. South Tambey field is large-scale gas-condensate deposit in Yamalo-Nenets region of Russia. It is located on the peninsula of Yamal. Stocks of natural gas on a field make about 1.3 trillion CBM, gas condensate 40-60 million tons. For upper cretaceous deltoid deposits of Tanomchinsky suite of a field heterogeneity and unevenness of layers on capacities, litho logical replacements in layer, pinch outs, probable existence of faults with shift of blocks and structural uncertainty on layer dips are characteristic. Now possibilities of new approaches in geosteering application for drilling horizontal wells are studied. As it is widely known already, the modern technological instruments allows to carry out azimuthally three-dimensional measurements in a well, being focused on definition of structural elements of a bedding of layers and measurement of distances to layer boundaries in real time. Information received during drilling together with its structural and petrophysical interpretation allows trying new approach which can possible to call three-dimensional geosteering. The geological department of JSC Yamal LNG carried out appraisal job with full application of expanded LWD complex and geosteering service when drilling sidetrack of well. It was planned to apply new advanced approach to geosteering which allowed updating in real time existing geological model, both in the structural plan, and in respect of continuous updating certain sector of modelled properties. In our case the porosity model was updated. Also, during drilling wells with horizontal ending, it is possible to use received logs for interpretation and further updating cubes of properties with porosity, permeability, collector distribution shaliness. In this report based on example of drilled well of South Tambey gas condensate field, results of the carried-out work are considered. Advantages of this innovative approach from the point of view of geology and modelling, and also from the point of view of geosteering overviewed.