| The lower submember of Es2 is one of the main puduction layers of the three area of Shanghe. Although study of the lower submember of Es2 has been done in a certain by the previous, such as the provenance is from the north-west or north of the study area, and it is mainly conventional low permeability reservoirs and so on. But which has entered a post-exploitation stages now has also exposed many problems in the development process. The main are:I As the previous reservoir evaluation instrument used by older, had made large data errors,which led to the inaccuracies of reservoir evaluation; II The heterogeneity of the reservoir is strong. Due to that the existence of the small sand bar makes the heterogeneity of the reservoir stronger, and because of the development process limited by the small fault blocks, less reserves of single layer and other conditions, the contradiction has been stronger constantly inner and between layers, and the degree of difficulty of development is becoming increasingly. Thus based on the previous study, it is necessary to do a deeper analysis of the lower submember of Es2, which can comprehend the characteristic of the reservoir.Through a full analysis of cores, cast sheet, well logging data and other data, using the relevant theory and technology, it has been done comprehensively and systematically of the sedimentology, reservoir petrology, physical and heterogeneity characteristics, sensitivity characteristics, fracture characteristics. The knowledge and achievements are as follows:(1)The types of rock mainly is feldspar quart silt-fine sandstone, compositional maturity medi u m, and structure maturity low. The pore is dominated by secondary pores, followed by primary porosity. Meanwhile it is small of the pore throat, which its shape is mainly punctiform, tubes bundle, and sheet, while the pore structure is well.(2)First,through the well logs re-interpretetaion, data standardization and normalization, the establishment of a reservoir property parameter database has been done which filters out the best fitting formula.Then based on it, the analysis of the por and the permeablility of the reservoir has been done by using the well log explanation,which show that the reservoir of the the lower submember of Es2 is mid por and low permeability.(3)After the standardization and normalization of the well log, it has been done to establish the physical template between the AC and porosity, and the template between porosity and permeability. Based on it, the evaluation criterion of the inner layer heterogeneity with the subjective and objective variable weight comprehensive evaluation model as the core, the differential, heterogeneity coefficient, variation coefficient and relative sorting coefficient as the evaluation parameter, has been done. And it acknowledges that the heterogeneity of the inner layers and the plane is stronger, while the heterogeneity of the interlayer is weak.(4)Using X-ray diffraction, scanning electron microscopy (sem), thin section identification, water flooding methods of sensitivity flow test, it shows that the sensitivity of the reservoir is weak, namely, its velocity sensitive is non or low, its water sensitivity is non or weak-medi μ m, its acid sensitivity is non or weak-mediμm, alkali sensitivity is weak-mediμm and non salt sensitivity. While taking advantage of the injection water method, it showed no fracture characteristics with improved reservoir properties of the role.(5)Using 3D geological modeling software- petrel simulates the geological properties and setting up the3D geological database of the lower submember of Es2. In combination with logging data,roughening the structure model appropriately, finally it is established of the porosity and permeability models of the lower submember of Es2. Comparing with research findings, the similarity is about 80% between them, which can be considered that the research achievements of reservoir of the lower submember of Es2 is a scientific and reliable, with the expectation to play a guiding role on the post-exploitation(6)After it, the control factors of the reservoir also has carried on the thorough discussion and analysis, while think that reservoir is mainly affected by sedimentation and diagenesis.(7)On this basis, selecting the corresponding parameters for evaluation of the reservoir in the area, the reservoir into three categories:Type I,is the best reservoir,with the better physical property, which the mouth bars are widespread; Type II, is the better reservoir, with the good physical property, which river mouth bars are developed well, but dominated by distal bar. Type III, is the worst reservoir, which mainly develop the between tributary bay. Among them, the type I and II is the main layer, which mainly distribute in the sand group 3 and 1+2. |
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