Lithologic Identification And Model Building Of Peperite In Jimsar Depression

Lucaogou formation in jimusar sag of junggar basin is a set of mixed deposits of saline lacustrine,whose lithofacies features are complex,mineral types are diverse,and logging response characteristics are poor,which greatly increases the difficulty of lithology identification and horizontal well drilling.At present,the geological orientation of horizontal Wells in lucaogou formation is mainly faced with the following two problems:(1)There is no quick lithology identification scheme to guide the field work,and the current classification scheme is not practical enough.(2)The response characteristics of conventional well logging are poor,which seriously affects the guiding work of horizontal Wells.In this paper,through XRD and XRF element data to identify the mixed lithology of lucaogou formation,and summarize the mineral content and element content of the typical rock types of lucaogou formation by semiquantitative method to establish a new mineral content and element content standard.On this basis,the control points are established according to the characteristics of elements and logging response for the trajectory adjustment and reservoir judgment during horizontal well drilling.Finally,based on reservoir geology,sedimentology,petroleum geology,reservoir modeling and other disciplines,the reservoir leading model of lucaogou formation is established to provide guidance for horizontal well construction.Studies have shown that:(1)Based on XRD,XRF data,the typical lithology characteristics of lucaogou formation were studied,and the six typical lithology of lucaogou formation could be effectively distinguished by curve feature method,curve intersection method,quantitative numerical method and map method.(2)The element and mineral content ranges of six typical lithology are summarized,and the element curve characteristics of six typical lithology are identified.After screening a variety of elements and mineral charts,it is found that K and Mg can distinguish the six lithology effectively,and the content ranges of K and Mg can be divided.(3)Ten marker layers with typical elements and electrical characteristics were identified,and on this basis,16 control points with typical element characteristics were established for the trajectory control and out-of-layer status judgment during horizontal well guiding process.(4)Based on the data of lithology,nuclear magnetic porosity and permeability,the geological guidance model of horizontal Wells in the study area is established.The results show that the upper "dessert" reservoir is more stable than the lower "dessert" reservoir,Feldspar lithic sandstone reservoir mainly develops in the upper "dessert" and the arenaceous dolomite reservoir mainly develops in the lower "dessert".(5)On this basis,the design of virtual X3 horizontal well is designed.The results show that the leading model can guide the reservoir development,and the control point can control the horizontal well trajectory.