The Research On The Development Technology Optimization Of Inclined Reservoir's Steamflooding In The Middle-late Stages

In 2006,Qi 40 in Liaohe Oilfield fully implemented the industrialization of steamflooding and transferred 149 wells and mobilized 37.74 million tons of petroleum geological reserves.At present,Qi 40 steamflooding is in the middle and late development stage,and has entered the phase of denudation adjustment.If the conventional steamflooding technology is still used,it is inevitable that the production will continue decreasing.In addition,the oil layer dip angle of Qi 40 steam-flooding area in Liaohe Oilfield is more than 10 ° Well group occupy a large proportion,of which only the inclination angle ?15 ° there are 22 wells group,accounting for the total number of well group 22/149 ? 1/7;presence of oil dip reservoir exacerbated the oversupply of steam on the development of the impact of the late seriously,Qi 40 Steam Drive current production status is not optimistic.Therefore,in this paper,according to 40 geologic features and practical problems of production,the theoretical and practical experimental studies on how to improve the development effect in the middle and late stage of steam dumping in high-dip reservoirs are conducted in depth.At present,Have a significant role in improving the overall technical level of China's steam flooding is also of great significance.In this paper,the mechanics model of oil and gas migration in inclined oil reservoirs is established by theoretical analysis of oil and gas(vapor)migration in the process of steep reservoir steam flooding,and the relationship between oil dip angle and steam migration direction and steam overrun is revealed.Based on the migration law,a new technical scheme of gravity-assisted steamflooding for inclined oil layer is proposed,and the specific methods and important technical parameters for applying the new technology are given.The result of this paper has guiding significance and practical value for improving the development effect and optimizing injection and production parameters of steep reservoir steamflooding.According to the principle of factorial analysis and liquid flow similarity,six similar criteria that can be used to simulate the production of steam flooding reservoirs are put forward.The calculation methods of mutual conversion between model and prototype parameters are proposed,and the proportion of physical simulation experiments of steam flooding Device.On the basis of this,a proportional physical simulation experiment of steep reservoir steam flooding was carried out and the experimental results in line with the actual production of Qi 40 were obtained.Through experiment,it is found that when the dip angle of oil layer is more than 12 °,the production well in the uphole part of the regular well net steam injection well is compared with the production well in the downtilt part.The steam breakthrough time of the production well in the up-dip part should be about 8 years ahead of schedule,It is almost impossible for the steam inside to reach the producer in the dip area.The location of the steam injection well must be adjusted to achieve the expected effect of steamflooding.A steam overlap degree analysis method is proposed based on the analysis of difference propulsion speed of steam in strata(top)layer and the lower layer(bottom)of inclined reservoir.Using this method evaluate the overlap degree of steam for different thickness and different angle,and the measures of slow the degree of steam overlap are put forward: After the formation dip angle ?10 °,according to different reservoir thickness to determine different perforation position,it should shoot two-thirds at the bottom of reservoir whose single layer thickness is 2 m ~ 5 m,and the bottom of reservoir with single layer thickness greater than 5 m should be perforated 1/2;According to the different inclination of reservoir to determine the different position of steam injection wells in well group,and 0 ~ 15 ° angle formation and steam injection well is located in the center of symmetry;15 ~ 25 ° angle formation and steam injection wells located 3/7 apart from downdip;25 ° angle formation and steam injection wells located 3/8 place apart from downdip.Based on the actual 40 reservoirs with high dip angle,aiming at the pursuit of crude oil recovery rate and maximum heat utilization rate,this paper presents an adjustment method of anti-9 point well pattern in the middle and later stages of steep reservoir steam flooding.The research shows that the 70 m well spacing and the anti-9-well pattern are more suitable for the current Qi40 inclined reservoir steam flooding.On the basis of well spacing and well pattern,the different steam injection well positions are selected as 0-10 ° situation,the injection well is located 70 m away from the production wells in the lower part;in the case of 11 ° ~ 20 °,the injection well is located 60 m away from the production wells in the lower part;the case where the injection well is located 46 m away from the production well in the lower part;,And the production of high partial well in steep reservoir steam drive well develops well at 1/5 of that in the lower part of the well.Different optimal injection and production parameters should be adopted in different stages of steam flooding.In this paper,Petrel software is also used to establish a three-dimensional geological model.The CMG-STARS software is used to establish the numerical analysis model.The numerical simulation completes the production history fitting of four typical well groups.The production dynamic analysis results are given.According to the typical well group steam Driven by numerical simulation results,it is suggested that the intermittent steamflooding or continuous steamflooding considering gravity aiding may be used in the middle and later stages of steamflooding in the Qi40 inclined reservoirs,and some of the blocks may adopt the stratified steamflooding method.At the end of the article,the feasibility of the new gravity-assisted steamflooding technology for inclined oil layer proposed in this paper is verified through field tests.The available injection and production parameters for on-site construction have been confirmed and good stimulation effects have been achieved.After adopting this new technology,there are 8 steam-tracing wells in the experimental zone that have returned to normal production.The daily output of the test area has risen from 150 tons to the maximum of 206 tons and currently produces 177 tons of crude oil per day.As of now,it has saved steam injection volume of 55,000 tons,An increase of 4760 tons of oil production,oil-gas ratio rose from 0.13 before the test to the current 0.18,a record economic benefit of 9.2 million yuan.The successful field test results show that the gravity-assisted steam-flooding technology in this paper is one of the effective technologies for increasing yield in the middle-late stages of steamflooding in a tilted reservoir(formation dip ?120).Similar to the reservoir conditions in this paper,it is suggested that the application of gravity-assisted steamflooding to improve the steam flooding effect.