The Logging Evaluation Of Chang 7 Member Of Yanchang Formation Tight Oil In Heshui Oilfield

With the deepening of the Ordos basin exploration and development,the exploration and development of the tight of oil and gas layer,together with the increase of oil reserve and production,has become the focus and hot issue of the further exploration and development.Tight oil reservoir group in basin Chang6 and Chang7 is widely dispersed,the total amount of tight oil resources is preliminarily estimated to be about 30 x 108 t,and the total amount of long and tight sandstone oil reservoir group resources about 9 x 108 t;the tight oil resources is a long-term stable practical replacing resources that will make sure the annual output of oil and gas equivalent of Changqing oilfield reach 5000 x 104 t.Currently,the prominent issues of Chang7 tight oil reservoir are poor physical property,complex influencing factors of oil production test,no obvious correlation with electrical and physical properties and reservoir characteristics,and low single well production.How to improve the single well production,accurate evaluation of the reservoir,reservoir classification and prediction capacity is now an urgent problem needs to be solved.This study is based on reservoir geological and petrophysical characteristics in Heshui area,by researching the form a complete set of rock physics experiment,logging interpretation method and promoting the application of new technology,it has established a classification of log evaluation standard,an interpretation model of the tight oil pertinence quantitative logging series and the tight oil reservoir logging,and a formation of low permeability sandstone reservoir logging evaluation techniques.Mainly,the following results have been obtained:(1),On the basis of reservoir characteristics research,the study has established the parameter calculation model for tight oil reservoir of Chang7 in Heshui area,and studied parameter quantitative calculation method of logging data of the pore structure,based on the dense oil reservoir based on nuclear magnetic resonance(NMR);(2),It has established the interpretation standard in the study area as well as the identification standard of the nuclear magnetic resonance(NMR)pore structure parameters of the oil and water layer,and it has also determined the reservoir lower limit of electrical and physical properties;(3),It has formed a map of the cracks development characteristics and cracks distribution results in the study area,and has analyzed the impact of the cracks development in the area of reservoir on the reconstruction effect and production capacity;(4),It has standardized the rock brittleness and in-situ stress parameter calibration,and perfected the industrialized figure pattern of the array acoustic processing results as well as the scale popularization and application of plots by adding brittleness index and stress profile;(5),It has preliminarily established reservoir classification standard for the Wells in the study area based on the pore structure.Through this study,the expected purpose of research has been achieved.This thesis has laid a foundation for tight oil reservoir fine quality evaluation and classification and the productivity prediction,it is also a foundation for scheme optimization of fracture reservoir and the improvement of single well production capacity;moreover,it can also provide technical support for a optimization of perforation,fracturing design,deployment and horizontal well borehole trajectory design,so as to achieve purpose of providing quality logging service to tight oil exploration and development.