Delicate Logging Evaluation Of Chang-10 Reservoir In Gao-XX Well Area

The Gao XX well zone was located in the yishan slope central south of the ordos basin,and the area was constructed as the west inclined monocline with high east and low west.The Chang-10 reservoir of Yanchang Formation,with geological features very different from north to south,complex pore structure,difficult identification of oil and water,and large error between the core analysis parameters and the reservoir parameters calculated by the original regional experience formula,was a newly developed reservoir in recent years.Therefore,based on the principle that the technology research served for production interpretation,the method of logging interpretation should be improved to establish an accurate reservoir parameter interpretation model,determine the evaluation standard of the research region,and enhance the logging interpretation coincidence rate.Closely around the exploration targets of Changqing oilfield,based on the exposed problems in the practical logging production and the conventional logging data combined with geology,testing,core analysis and imaging logging data,this paper carried out the research of six aspects as follow:(1)small layer division of Chang-10 reservoir in Gao XX well zone;(2)according to the description of the core phase and the logging phase,the sedimentary characteristics of the study area were determined;(3)study on the relationship among lithology,physical property,oil content and electric property in the reservoir.(4)reservoir evaluation by imaging logging;(5)the calculation formula of porosity and permeability in Chang-10 reservoir was determined by core calibration logging.(6)the logging interpretation chart and the lower limit standard of effective thickness were re-established to determine the oil and water layer for the the second interpretation.Then,in Chang-10 reservoir,the varying pattern of lithology,physical property,oil content and electric property was clarified,the interpretation standard for oil and water layer was determined and the method of using logging data to identify oil and water layer was set up.Adopting the crossplot method of sound waves &formation deep resistivity,the intrusion characteristic analysis method,the construction auxiliary discrimination method and the identification of oil and water layer by the nuclear magnetic resonance logging,a set of comprehensive logging evaluation methods for the Chang-10 reservoir in Gao XX well zone were developed.In the interpretation and evaluation of the Gao XX well area,the above research results had played an important role and had achieved good results.Using the core calibration logging,the calculation formula of porosity and permeability of Chang-10 reservoir was determined.85% of the absolute error of porosity was less than 1.5%,and 88% of the absolute error of permeability was within an order of magnitude.The logging interpretation chart and the lower limit standard of effective thickness were re-established to carry out the second interpretation with 95% coincidence rate of interpretation.The log interpretation chart and the lower limit of effective thickness were reestablished,and the log interpretation was carried out,and the interpretation of the coincidence rate was 95%.