Determination of Stress Directions From the Scale of the Volga-Ural Region to the Local Scale of the Field in the Orenburg Region For Optimize the Development System

摘要

Study of changes of regional horizontal stress in the Orenburg region in order to optimize the development of Volga-Ural region oil fields has not been carried out before.The research is aimed at obtaining the results of the connection between direct(azimuthal electric microlateral logging)and indirect(work wells,hydraulic fracturing,tracer studies)methods to determine the direction of maximum stress in a vast territory of two regions:Samara and Orenburg.A regional map based on the systematized measurements of the azimuthal electric microimager was constructed.This map does not contradict the tectonic and geological concepts of the Devonian system formation,which is the main largest reserve for the Volga-Ural region fields.A local analysis of the direct and indirect methods relationship to determine the direction of maximum stress at the level of two fields of the Pervomaisky group-G1 and RK1 was conducted.This analysis was performed due to the large amount of input information from indirect data and in order to confirm the distribution of values in the peripheral zone of the regional map,where the reliability of mapping is reduced.As a result of localization,a relationship was revealed,which allowed us to scale the analysis methodology to the existing fields of Volga-Ural region and to increase the number of indirect studies(tracer studies),as a cheaper analogue to azimuthal electric microblock logging.Positive conclusions on the interconnection of methods made it possible to optimize the development of a perspective area in the eastern part of the RK1 field with the recommended reorientation of the direction horizontal wellbores with the subsequent economic effect for the company.