The Reservoir Comprehensive Evaluation Of Triassic Lower Oil Formation In The Main Area Of 1st Block Of Tahe Oilfield

The reservoir of the 1st block of Tahe Oilfield is one with a complicated fault system and edge-bottom water in the lower section of the lower oil formation. At present, the main problem is the breakthrough water in production wells. Water volume is increased too fast with over -declined oil volume. Production fluid lateral section of the horizontal wells sees abnormal features. The overall production level of reservoirs declines. The treatment is difficult to find in the high water stage, and it is not very effective to block water.All above factors pose a serious threat to reservoirs.Therefore necessary to re-understanding of the reservoir, the reservoir area to make further evaluation.In order to scientific and reasonable to predict reservoir distribution in the region, author in-depth study of the area of the first three main oil reservoir characteristics of a sublayer. Finally, combined four factors of sexual relations and reservoir control and minimum standards for the research results of reservoir, reasonable forecasted reasonably the distribution of favorable reservoir.Based on summing up and collating the previous studies of the 1st block of Tahe Oilfield , combination of advanced technologies and method to carry out scrutiny, this paper takes the drillinganalytics, the geophysical well logging ,the seismology ,the experimental data and the traditional geology method to study the characteristics of Lower Oil Formation by using available exploration and production data in study area. In the previous division and a small layer on the basis of this observation of cores, author reviewed and makeuped the sublayer division of the main layers of 26 vertical wells, straight guide hole wells and 19 horizontal wells of the study area.The study area of Lower Oil Formation in braided main channel development area is a thick braided river deltaic deposit. The main feature of profile is more than the performance with large sets of positive rhythm braided sand, the sand body widely distributed, multi-branching or merger braided stream was the depositional characteristics, the sublayer of Lower Oil Formation development braided main stream channel microfacies, little interchannel microfacies and even less non-development, development of interchannel microfacies are only sporadic local exist.Based on study of petrologic characteristics, properties characteristics and pore structure in Lower oil formation,we regard that the lithology of study area is mainly with The main types of sandstone are feldspathic litharenite and lithic arkose ,the pore structure of mesoporous, mesopore, high permeability, uniform coarse pore throat distribution of reservoir. Aim at specificity for the reservoir, author combined electric characteristics of well logging and interpretation of results of physical properties and study the layer in layer, flat, interlayer reservoir heterogeneity.Author study the layer in layer heterogeneity mainly at layer in layer's rhythm characteristic of permeability and the type of interbed and interbed's distribute. Plane heterogeneity mainly study sand distribution, physical parameters in areas such as. interlayer heterogeneity mainly use the means of permeability, range, coefficient of sudden to evaluate the degree of non-homogeneous of interlayer. Moreover, the study shows that the reservoir property is clearly under the control of composition of reservoir rocks, sedimentary facies and reservoir diagenesis and so on. The first is lithogenesis during the factors of thin out porosity and permeability, the second is compaction. Towards to the good permeability, pore throat development is the most important factors and the next is particular denudation. According to physical property and pore structure,the author got the criterion of reservoir classification and defined 4 container rock.Based on the study of sedimentary facies,reservoir parameters and sand plane distribution,the author comprehensively evaluated the character of 1,2,3 sublayer for Triassic Lower Oil Formation in the 1st Block of Tahe Oilfield, the study shows thatâ…¡,â…¢t ype of reservoir is mainly,â… -type reservoir is only in TK103-T114-TK121 and TK120-TK112-S29 wells development zones.