Study On Prediction Of Carbonate Fractures Based On Multi-Scale

Currently the fracture reservoirs is accounting the proportion of reservoir findings increasingly,the reserves and production is also in increasing proportion accordingly.The focus of researches is more sloped to irregular reservoirs rather than that of structural traps reservoir,the fractures of reservoir is not only the transport corridor of liquids in oil reservoir,but also the fine reservoir space for oil and gas,thus it shall has important significance for improving the output of oil reservoirs,and it's already the hot topic among the scientific analysis field to make research on fracture prediction.It's quite complicated and a system engineering for research on reservoir fractures,within a single scale it cannot represent the features of fractures inside reservoir even better,so the analysis via the angel of multi-scale to fractures is needed to develop.In this study,by combining IR Spectrum imaging with multi-dimension analysis,to perform the study on fractures' microscopic characteristics by application of Infra-Red Spectrum technology,then determine the availability and formation period of carbonate fractures under microscopic characteristics;to make prediction study on carbonate fractures within reservoir area by using surveyed data and geologic information of the wells,and then predict the distribution of fracture development states.The results of the study indicate that:(1)In study area there contains Organic hydrocarbon compounds and liquid inclusion inside the core,the reservoir fractures exist mainly inside dolomite medium,There's quite small filling degree just with 26.014% of alkane organics in fractures,but the bigger proportion with 51.691% of brine inclusions inside.The fracture in the core is a great gap,with quite fine availability.(2)In study area there're two main formation period for oil and gas fractures in Qianshan,the one is between late depositions of Dongying Formation to medium deposition ofMinghuazhen Formation;another is deposition between Oligocene sand two Section to Eocene sand three Section.(3)Through the numerical simulation calculation,can get the stress value inside the top stratum of reservoir area in such Wumishan Deformation ranging from 26 to 102 MPa.The higher stress value exists on the southwest and northeast part;the stress value inside the fractures is smaller than that of continuous stratum.(4)The development index inside fractures and the transitional region of its neighboring fracture is quite big;it shall be fracture developing region.The development index in both southwest and northeast direction increases gradually,it shall belong to fracture developing region also.For the remained part,including the southeast and northwest part,shall be both fracture slightly-developing region.The contour curve around the fracture edge ranges fast;the fracture distribution presents a block distribution accordingly effected by the stress releasing of rock stratum.By comparing the Contour curve figure of Fracture development index and the wells distribution figure,more intensive wells distribution is found just near the fracture area and those areas with great gap of fracture towards to southwest / northeast direction,and other regions with sparse wells distribution.The prediction study on fracture developing area of reservoir is in conformity with the wells distribution,it also testify that this study is in accordance with the engineering.