A double-pipe SAGD long horizontal well uniform steam injection numerical simulation method considering coupling of an oil reservoir and a shaft

Abstract

The invention relates to a double-pipe SAGD long horizontal well uniform steam injection numerical simulation method considering coupling of an oil reservoir and a shaft, and the method comprises thesteps: establishing a reservoir internal seepage and heat transfer mathematical model in a three-dimensional three-phase heavy oil reservoir double-pipe steam injection development process from the aspects of mass conservation and energy conservation; And establishing a flowing and heat transfer mathematical model in the wellbore in the steam injection process according to the variable-mass bidirectional convergence flow characteristic of the fluid in the wellbore and the structural characteristics of the slotted screen pipe column. The method is based on pressure and temperature continuity principles. the wellbore model and the reservoir model are coupled; the model is solved by adopting a fully implicit finite difference method and an iteration technology; By means of the model, the distribution rule of parameters such as pressure, temperature, steam inflow and wellbore on-way steam pressure, temperature and dryness at any moment in the simultaneous steam injection process of the double-pipe SAGD long pipe and the double-pipe SAGD short pipe can be predicted, proper steam injection parameters are selected, the stratum heating uniformity degree is improved, and a reasonable development scheme is made.

Description

technical field [0001] The invention relates to a numerical simulation method for uniform steam injection in double-pipe SAGD long horizontal wells considering the coupling of reservoirs and wellbores, and belongs to the technical field of numerical simulation of heavy oil reservoir development. Background technique [0002] Heavy oil reservoirs are one of the most important types of reservoirs in the world. The world's heavy oil (including bitumen, etc.) resources are very rich, accounting for about 70% of the world's total oil resources. my country's heavy oil resources are mainly distributed in Liaohe, Xinjiang, Shengli and other oil fields, with geological reserves of 20.6×10 8 t, a large amount of heavy oil resources need to be exploited urgently. Therefore, at the moment when the development of conventional oil and gas resources is becoming more and more difficult and energy conflicts are becoming more and more prominent, the economical and efficient development of hea...

AI Technical Summary

Problems solved by technology

The research on the double-pipe model mainly includes two aspects: on the one hand, the double-pipe is equivalent to a single pipe string, which cannot be used for the simulation calculation of parameters such as the long tubing in the horizontal section of the double-pipe and the pressure field and temperature field of the annular space; on the other hand, the current Some models mainly consider the flow and heat transfer of fluid in the wellbore, but the influence of reservoir pressure, temperature, saturation, etc. that change with time during steam injection is not fully considered

[0005] The simultaneous steam injection process of double-pipe SAGD with long and short pipes is a dynamic process in which the wellbore of a horizontal well interacts with the reservoir. The existing theories and methods do not fully consider the reservoir physical parameters changing with time. Influenced by the distribution of key parameters along the wellbore during the process, and the length of the horizontal section of the simulated horizontal well is generally about 300 meters, there are certain errors in the simulation results, which cannot be used for oil production at any time during the simultaneous steam injection process of double-tube SAGD long and short tubes. Prediction of Change Law of Key Parameters in Reservoir and Wellbore

Images