Study On Gas Injection Scheme Of Carbonate Rock Fracture - Type Reservoir In Tahe District

Different from other kinds of carbonate reservoir, Tahe carbonate reservoir of Ordovician system has extremely serious heterogeneity and complex flowing law. Its development history shows that this type of reservoir has bigger decline rate and lower recovery factor. Through many years’experience accumulation and tackling several kinds of technology project, the northwest oilfield branch company of SINPEC has already excogitated one type of Tahe carbonate reservoir’s waterflooding development technology, this technology effectively slowdowns the reservoir’s decline rate and enhances the recovery factor. But when deeply using waterflooding, the water injection efficiency became worse, in order to solve this problem, a field experiment of single well gas injection was conducted to improve the recovery factor, premliminary result shows that gas injection effects well. Although the qualitative mechanism is clear, but the complex geological conditions and the low reliability of3D geplogical model and the unclear parameters of gas injection production result in the lack of the detail gas injection scheme. In order to talking this problem, this paper focus on the study of two related issues, one is to improve the geological model, the other one is to optimize the gas injection prarmeters and design the gas injection scheme which is based on the new geological model.This paper regards the4district of Tahe oilfield as the research background, based on the principle of well selection and select two wells which have obviously structural characteristics. Through the analysis of static and dynamic data of the chosing two wells to find out the influencing factors which process the gas injection development. And then using the technology of3D geological moding combined with numerical simulation to analysis the feasibility of gas ingjection, through the comparison of various types of injection production parameters to improve the design of gas injection in the end.This paper proposes a methed of valuating virtual cave system’s logging carve which is based on the equivalent single medium model, while using a method to solve the difficulty of building cave system’s permeability model which can make the3D geological model more precisely in accordance with the real geological condition. In order to increase the reserve’s recovery degree, focusing on the high point of the structure while using N2injection. This paper adopted numerical simulation to optimize different kinds of gas injection parameters which finially forms the detail gas injection scheme, and this will use for reference to the Tahe facture-cave type reservoir’s gas injection development.