The Development And Assesment Of Fault-association Fracture System

The development of natural fracture in reservoir often decide the distribution of oil and gas, impact the filtrate characteristics of oil and gas development, so the study of natural fracture's characteristics, causes and distribution have great significance to fracture reservoir exploration and development. From domestic and abroad previous research work on the fracture, the causes of the fracture is very complex, be controlled by many factors, and very difficult. The causes of the many types of fracture, the symbiotic fracture which related with fault have done some research by predecessor, received some awareness, but it is lack of systematic and quantitative evaluation of the distribution. Text to UPPER SHUAIBA formation, Daleel Oilfield, Oman reservoir an example, carry out the typical fault symbiotic fracture studies, provide reference and inspiration for the fault symbiotic fracture zone studyThis paper is fully integrated geological background of the study area, first of all, through the core and core thin, the fracture was observed, described and been statistic, and combined with single-well analysis of fracture direction, inclination and parameters, summarized the fracture characteristics of the study area systematically. Combining the study area's fracture development characteristics and the evolution of the tectonic and stress field, were analysis and comparison of fault fracture symbiotic mechanism and the breakdown characteristics, recognized that the fracture was controlled by the fault, is fault symbiotic fracture. Fault identification is the premise of fault symbiotic fracture study, through the use of spectral decomposition of seismic data converted from time domain to frequency domain, according a single well drilling meeting fault as valid condition, in the band edge, respectively, the use of low-frequency phase data and high - frequency phase data for a large body of small faults and fault identification. Identification of fracture in a single well is often the focus of the fracture study, but also the key to the evaluation of fracture distribution, mainly to take a horizontal well logging and imaging of conventional vertical well log data to identify fracture. According to the image features by imaging logging ,it recognized continuous high conductivity fracture, non-continuous high conductivity fracture, continuous high resistant fracture, non-continuous high resistant fracture, and calculated the relevant fracture occurrence and parameters. Through the analysis of conventional logging response to the fracture, the study area fracture is often manifested that low effective density, high neutron porosity, high-acoustic, high-resistivity range of the depth of the lateral deviation, but because of non-fracture on the impact of conventional logging, the effective identification of fracture often could not rely on a single logging series, a single method; therefore fracture porosity, width parameters are calculated by dual laterolog in text. Applied identification analysis to establish fracture identification function by a series of logging to identify, applied R / S analysis method to calculate fractal Well fractal dimension, and finally, combined the integrated characteristics of core fracture to establish conventional logging standard to identify fracture. Fracture distribution is carried out based on the fracture density, through the samples of 20 typical fault, identified the fracture and calculated its density of the vicinal drilling well, established the fracture density function near the fault, and classified in accordance with the function type, and ultimately according to the fault scale (fault length) established large, medium and small fault-controlled fracture density function. In accordance with the fault density of fracture in the control function, designed relevant calculation method, developed a computer program, calculated to the intended layer's fracture density in study area, completed the distribution of fracture forecast. Finally, through all the fracture identify results of single well and the production reflects to the dynamic characteristics, verified and evaluated the understanding of the law of fracture development and the fracture predicting distribution in the study area.In this paper, some exploratory works have been done to the fault symbiotic fracture's systematic research, ideas and methods of quantitative evaluation establishment. And attend to combine the research results with the geology, well logging, production data, etc., which reflects the characteristics of the actual fracture. Research results have guiding significance to the block layer's development of study area. Especially, provide a practical basis to the comprehensive management about the current development water-injection problems and the follow-up oil block's development programming.