The Research On Uniform Steam Injection Mode And Parameter Optimization In SAGD Horizontal Well

Steam-assisted gravity drainage(SAGD),as one of the most effective development methods for the exploitation of heavy oil reservoirs,has been carried out in advance experiments in Canada gradually applied to production practice.Production practice shows that SAGD technology is very helpful to improve the development effect of heavy oil.However,in the practice of SAGD production,the problems of uneven development of steam absorption profiles along the well direction and uneven production of oil reservoirs occurred in long horizontal well sections.In this paper,through the experimental method that can directly observe the development law of the steam suction profile,systematically study the steam injection of the SAGD horizontal well section,fully understand the development law of the steam suction profile along the horizontal well section,and optimize the steam injection string of the horizontal well.Thus,an effective uniform steam injection method for SAGD horizontal wells is formed,which has important practical significance for improving the development effect of SAGD horizontal wells in my country.This paper first designs and conducts two-dimensional experiments with different steam injection methods for SAGD horizontal wells.Through indoor experiments,the heat and mass transfer of SAGD horizontal wells are observed during the experiment,and the temperature,pressure,remaining oil distribution and productivity changes are studied.The influence of the depth of the short pipe on the uniformity of the double-pipe steam injection,and the influence of the number of steam injection points and the depth of the short pipe on the uniformity of the multi-point steam injection are studied.Finally,this article is based on experiments,using numerical simulation software to verify and supplement the experiments.Finally,through the establishment of a geological model,the study on the optimization of uniform steam injection parameters and effect prediction of SAGD horizontal wells was completed.The research results show that the multi-point steam injection method develops the most uniform steam absorption profile along the well direction,and the steam chambers are distributed along the horizontal section.The steam cavity at the middle and toe ends of the conventional steam injection method is underdeveloped,and the steam suction profile accounts for 1/4 of the length of the horizontal section.The steam chamber in the middle section of the double-pipe steam injection method is underdeveloped,and the steam suction profile accounts for 1/3 of the total length of the horizontal section.When the short pipe running depth of the double-tube steam injection method is extended to 1/3 of the horizontal section,the heel end of the double-tube steam injection method develops more evenly,reaching 1/2 of the length of the horizontal well.The injected steam energy get more effective use.There is an optimal value for the number of steam injection points in the multi-point steam injection mode.With the continuous increase of the number of steam injection points,the uniformity of the steam cavity first increases and then decreases.Combined with reservoir geological data,through the optimization method of injection and production parameters and the optimization of steam injection point,the uniformity of steam cavity development along the way has been improved by 13.39%,the cumulative oil production has increased by 1.01×10~5 m~3,the maximum precipitation has reached 7.13%,and the gasoline ratio reduction of 24.93%.