The Method Of Stress Interpretation In Natural Fractured Stratum And Its Application

In the petroleum industry,the study of in-situ stress is a hot spot and a difficult point,especially in fractured formations where natural fractures are abnormally developed.The existence of natural fractures has a great influence on drilling construction,exploration and development of oil and gas,and also brings great uncertainty to the accurate calculation of in-situ stress in fractured formations.The hydraulic fracturing method and logging method are used to calculate the formations in-situ stress,but it is not specific for the fractured formations,and sometimes the error is large.Although the hydraulic testing of pre-existing fractures is applicable to the calculation of the in-situ stress of fractured formations,it needs a lot of the number of tests,and the calculation process is cumbersome.This paper is based on the hydraulic testing of pre-existing fractures for in-situ stress measurement.Firstly,the software of Techlog and log data is used to introduce the method of identification and analysis of natural fractures in fractured formations.Then based on tensor coordinate transformation and the basic problems of elasticity mechanics analyze the normal stress on the fracture surface.The relationship between normal stress and in-situ stress on the fracture surface was established.Four methods for the interpretation of in-situ stress in fractured formations were presented in different situations.Finally,select three wells for example use.The results of the calculation shows that the method of stress interpretation is reliable.