Research Of Well Logging Evaluation Method For Daanzai Carbonate Reservoirs In Longgang Area

The Jurossic carbonate reservoirs of the Daanzai segment in Longgang area presentcomparatively great heterogeneity and anistropy, which make it difficult to achieve effectivereservoir evaluation and parameters calculation. Based on petrophysical experiments, thisthesis establishes a set of logging evaluation method which is suitable for carbonate reservoirof Daanzai segment, in combination with conventional logging data and imaging loggingdata.The analysis of conventional logging data, imaging logging data, core data, slice data,mercury penetration data show that the lithology is major in limestone, porosity andpermeability are very low, and electrical characteristics is complex in Daanzai segmentreservoir. Fracture development or not is significant controlling factors of reservoireffectiveness. Although matrix porosity of carbonate reservoirs in Daanzai segment is low, butit can act as important reservoir space. Analysis showes that the reservoir space in Daanzaisegment is mainly of fracture-porosity type. Dual-porosity crossplot method is adopted tocalculate the total porosity and a fast algotithm for computing based on dual laterolog isadopted to calculate the fracture porosity. In view of the special characteristics of complexmatrix pore texture, permeability interpretation model based on flow unit FZI is establishedwhich improves the accuracy of the reservoir interpretation and evaluation; Rock electricalproperties experiment of carbonate rock samples in Daanzai segment is carried out, whichshowes the rock electrical relationship of core, and the parameters of saturation computationmodel are determined.The effectiveness of the Daanzai segment reservoir is studied from two levels, the matrixporosity and the development of fracture. Based on the mercury penetration and NMRexperiment, the pore texture of reservoir matrix is divided into three types, the threeclascification criteria for matrix porosity is identified; the distribution scale of reservoirfracture porosity is counted and analyzed, additionally, the three clascification criteria offracture porosity is determined. Finally, based on the matrix porosity and the fracture porosity leve, the reservoir of Daanzai segment is divided into three types, which is verified with thedeliverability level based on testing data.Using the method of multi-parameter integration contrast, sensitive parameters includingmatrix porosity, fracture porosity, three porosity logging value, deep lateral resistibity areselected to establish fluid identification crossplot and establish the identification criteria ofdry layer and effective reservoir, which proved to have high fluid identification coincidencerate through verfication.