Layered polymer injection process Overcome the recovery problem
A few days ago, the Shengli Oilfield Development Office organized the leaders, experts and related technicians of the Oil Production Institute, Gudong, Gudao and Shengli Oil Production Plant to hold a concentric double-pipe layered polymer injection technology seminar in the third production center of Gudong Oil Production Plant. G06-23-474 well for on-site observation.
日前，胜利油田开发处组织采油院、 孤东、孤岛、胜利采油厂的领导、专家及相关技术人员在孤东采油厂三采中心召开了同心双管分层注聚技术研讨会. 并到G06-23-474井进行现场观摩。
On-site observation shows that the concentric double-pipe layered polymer injection process effectively solves the problem of difficult polymer injection profile testing in polymer injection wells, greatly reduces the loss of tubing string fit, and also solves the problem of polymer injection tool blockage, and the injection cycle of a single well. significantly prolonged. At present, the average injection cycle of the measure wells in Gudong Oil Production Plant reaches 255 days, and the longest one has exceeded 400 days.
Continuous innovation of three mining technology
Polymer flooding has become an important technical means to increase production, improve oil recovery, and maintain the sustainable development of oilfields in the later stage of high water cut. Polymer flooding development is like water flooding, and there are also interlayer contradictions in the process of opening. The problem of single-layer inrush of oil layer c. If the general injection method is adopted, the polymer solution mainly enters the high-permeability layer, and these layers correspond to the oil wells. It will seriously affect the development effect of polymer injection flooding.
As of September 2008, Gudong Oil Production Plant has 5 positive injection units and 226 polymer injection wells, with a daily injection volume of 20,803m3/d and a daily oil production of 2,084.3 tons. In 2007, the annual oil production of the positive injection unit was 57.7 x 104 tons, accounting for 21.9% of the total output of the oil extraction plant. It is estimated that the annual oil production in 200B will be 70.8 x 104 tons, accounting for 27.2%. Statistics on the number of layers injected into the polymer injection wells in the positive injection unit can show that there are 161D wells with more than two layers injected, accounting for 71.9% of the total number of polymer injection wells.
截止2008年9月，孤东采油厂有5 个正注单元，226 口注聚井，日注入量 20803m3/d,日产油2084.3吨。2007年正注单元年产油57.7 x 104吨，占采油厂总产量的21.9%,预计200B年年产油70.8x104吨，占27.2%,三采产置的高 低严重影响采油厂产量的稳定。对正注单 元注聚井注入层数进行统计可以看到，注两层以上的井有161D,占注聚井总数的71.9%。
The third production technician of Gudong Oil Production Plant found that the permeability difference of different layers of each unit is quite different. The permeability difference of the third and fourth areas is 9.4, and the permeability difference of the second area has also reached 8.2. . Taking the second-zone polymer injection zone as an example, due to the large difference in permeability, there are also significant differences in the amount of polymer absorption in each layer. Among them, 54 and 45 have better absorbing and polymerizing conditions, while 42 and 53 have relatively poor absorbing and polymerizing conditions. After a period of polymer injection, the difference in permeability between different layers of some wells has become larger, and the high-permeability layer has larger absorbing and polymerizing capacity, while the original absorbing and polymerizing conditions are poor. Therefore, the purpose of adjusting the absorption profile cannot be achieved by the high viscosity of the polymer. That is to say, it is hoped to improve the absorption profile through the polymer, so as to improve the contradiction between layers and improve the yield of remaining oil. wishes cannot be realized.
The layered polymer injection technology can improve the polymer control and injection profile, control the inrush phenomenon of the polymer solution along the high permeability strip, so that the difficult-to-produce oil layers can be effectively developed, and solve the problem of large differences in the absorption and polymerization between the layers of the polymer flooding wells , to achieve reasonable distribution between layers, prolong the validity period of polymer Li, and further improve the recovery rate.
The world focuses on layered polymer injection process
Foreign polymer flooding began in the late 1950s, the former Soviet Union's Orleans Oilfield and Arland Oilfield, Canada's Horsefly Lake Oilfield and Rapdan Oilfield, France's Chatearenard Oilfield and Courtenay Test Area, the United States, Germany, Oman and more. All oilfields have carried out the industrial promotion of polymer oil. Since foreign oil reservoirs are generally developed with multiple sets of well patterns or a single set of well patterns, and each set of wells is generally injected with bare tubing, the research on polymer layered injection technology is aimed at Rarely.
国外的聚合物驱油开始于上世纪50 年代末，前苏联的奥尔良油田和阿尔兰油田、加拿大的Horsefly Lake油田和Rapdan油田、法国的Chatearenard油用和Courtenay试验区、美国、德国、阿曼的多个油田都开展了聚合物驱油工业推广，由于国外油藏一般采用多套井网或单套井网开发，每套井冋采用光油管笼统注入，所以针对聚合物分层注入技术上的研究并不多见。
Domestic research on layered polymer injection technology began in the 1990s. Daqing Oilfield started early in this regard. Jianghan, Dagang, Henan, Liaohe and other oilfields also rely on Daqing technology to conduct research on polymer layered injection technology. and application. At present, the most widely used layered polymer injection technologies in China mainly include reverse polymer injection technology, concentric single-tube layered polymer injection technology, and oil-casing separate injection technology.
The inverted injection process pipe string is composed of a hollow water distributor, a packer and a bottom ball. The core of the hollow water distributor is extended, and the nozzle is enlarged to reduce the shearing of the polymer, and the oil layer that is temporarily not injected is put into death. The core, realizes the injection of a single layer segment. This process does not need to be tested. The injection flow rate is read from the surface flow meter, but it cannot meet the layered injection requirements of the two layers at the same time. Repeated injection and fishing can easily cause pressure fluctuations, resulting in formation rebate and affect normal injection. In addition, the injection cycle To be sure, further research needs to be done.
The concentric single-pipe layered injection process is mainly composed of a packer, a distributor and a bottom valve. The dispenser adopts a double-layer tubular structure. There are equidistant annular grooves on the outer wall of the inner tube, and a throttling gap is formed with the inner wall of the outer tube. On the basis of retaining the polymer stickiness, the purpose of throttling and reducing pressure is achieved. , adjust the length of the throttle core during deployment. Due to the small gap of the annular groove, it is easy to block the annular groove when the wellbore mechanical impurity content is high or the formation returns, which affects the normal injection.
The oil-casing dispensing technology is relatively simple in the structure of the pipe string, using the oil pipe and the oil-casing annulus to realize the two-layer dispensing of the polymer. This stratified injection technology has the advantage of being free of measurement, adjustment, and fishing. However, due to the serious damage to the casing due to the injection pressure, corrosion and scaling, the stratified injection pressure is adjusted by the ground splitter device, which will inevitably cause the pressure difference before and after the ground splitter device to overshoot. If it is too large, the viscosity loss of the polymer solution is too large, which is not conducive to the oil control effect of the beard injection. At the same time, the strong corrosiveness of the polymer solution can easily cause permanent damage to the casing, and sand production in the oil layer can easily lead to sand burial of the pipe string, which affects the normal injection.
At present, the polymer stratification test instrument mainly adopts the underground storage electromagnetic flowmeter for water injection. The test instrument is lowered to 5 meters below the position of the lowest stage distributing device with a steel wire. Sit into the agglomerator. After positioning, the liquid outlet hole on the test sealing section corresponds to the liquid inlet hole of the throttle core in the agglomerator. The upper and lower parts of the hole are sealed by a sealing ring. And the distributing device enters the destination layer. After the test of the layer is completed, the previous layer is lifted up and tested in turn. For polymer injection in Shengli Oilfield, slush water is used to configure mother liquor, which is mixed with sewage and injected into the formation. Due to uneven mixing, there are "fish-eye"-shaped agglomerates in the injected liquid, and the error of test data is relatively large.
目前聚合物分层测试仪器主要采用注水用井下存储式电磁流量计，用钢丝将测试仪器下到最下一级配聚器位置以下5 米，上提测试仪器将测试密封段定位后爪打开并坐入配聚器内，定位后测试密封段上的出液孔与配聚器内节流芯的进液孔相对应，孔的上下由密封圈密封，聚合物溶液 经流量计、测试密封段及配聚器进入目的层。该层段测试完后依次上提测试上一层段。胜利油田注聚采用淸水配置母液，与污水混合注入地层，由于混合不均匀，注 入液中有"鱼眼”状结块，测试数据误差相对较大。
In order to further enhance the oil recovery by polymer flooding, it is necessary to realize the layered injection of polymer. Retain the injection viscosity of the polymer to the maximum extent, realize the layered test and deployment of the polymer, improve the displacement effect of the corresponding oil layer, and develop a simple, economical and effective concentric double-pipe split according to different types of oil reservoirs and injection well conditions The polymer injection process string has become the direction of technical research in various oilfields at home and abroad.
New layered injection craft pipe string Design
The technicians of Gudong Oil Production Plant designed the stratified polymer injection string. The main downhole tools are: seal compensator, inner pipe hanger, downhole packer, large-diameter screen and downhole commutator according to different layers. Under different pressure conditions, a forward and reverse concentric double-pipe layered polymer injection string is formed (Fig. 1, Fig. 2).
Positive concentric double-pipe layered polymer injection string: It consists of a seal feeder, an inner pipe hanger, a downhole packer, a downhole commutator, § 89mm nitriding tubing and § 48mm sea nitrogen tubing. It is mainly suitable for layered polymer injection in two-stage polymer injection wells with higher upper layer pressure and lower lower layer pressure. Reverse concentric double-pipe layered polymer injection pipe string; composed of sealing compensator, inner pipe hanger, downhole packer, large-diameter screen pipe, § 89 meters of nitriding oil pipe and § 48 mm nitriding oil pipe, mainly suitable for Layered polymer injection in two-stage polymer injection wells with lower upper layer pressure and higher lower layer pressure.
正向同心双管分层注聚管柱：由密封补供器、内管悬挂器、井下封隔器、井下换向器、§89亳米渗氮油管和§48亳 米海氮油管组成，主要适用于上层压力高下层压力低一级两段注聚井的分层注聚。反向同心双管分层注聚管柱；由密封补偿器、内管悬挂器、井下封隔器、大通径筛 管、§89臺米渗氮油管和§48毫米渗氮油管组成，主要适用于上层压力低下层压 力高一级两段注聚井的分层注聚。
The ground process of the ground supporting device has the functions of completing the diversion, accurate metering and auxiliary pressure control, and at the same time, it is necessary to improve the station retention rate in the whole process as much as possible, and the ground process has been optimized for this purpose. Mainly developed a balanced low-shear valve, selected an electromagnetic flowmeter, and designed a standard ground process. Field tests show that the optimized ground supporting device achieves the goals of accurate diversion, accurate metering and high pressure control within a certain range.
Development of the balanced low-shear regulator: After the positive and negative improvement of the pipe string, different layered polymer injection pipe strings can be selected for different oil pressure differences. However, due to the limited frictional resistance provided by the tubing, for wells with large interlayer pressure differences, more pressure control capability on the surface is required (Fig. 3).
平衡式低剪切调节御的研制：在对管柱进行正、反向改进后，能针对不同 油层压差选择不同的分层注聚管柱。但 由于油管能提供的摩擦阻力有限，对层间压差较大的井，还需要地面提供更多的控压能力（图3 ）。
Valve design: In order to reduce the mechanical shearing of the valve seat to the polymer solution, the valve core is designed with a conical shape, and the adjustment channel is an arc shape; the seal between the valve core and the valve seat is made of surfacing alloy material, which has Strong erosion resistance can ensure the tightness of the valve; the valve transmission system seal adopts the depressurization technology to ensure the flexibility of Minmen adjustment and achieve the purpose of balanced adjustment.
阀门设计：为降低阀座对聚合物溶液貼度的机械剪切，阀芯采用圆锥形设计，调节通道为圖弧形；存阀芯与阀座的密封处采用堆焊合金材料，该材料具有较强的耐冲刷性，可以保 证阀门的密封性；阀门传动系统密封采用 降压技术，保证闽门调节的灵活性，达到平衡式调节的目的。
The performance index of the regulating valve: the maximum working pressure is 20 MPa. Under the working pressure of 16 MPa, it can effectively cut off the flow of liquid without leakage. Within the maximum working flow range, the flow rate of the polymer solution can be adjusted arbitrarily. Not less than 1m3/h, the control pressure difference is within 1 trillion, and the viscosity retention rate of the polymer solution is greater than 90% 。
调节阀性能指标：最大工作压力20兆帕，在16兆的工作压力下，可以有效截止液体流动而不发生 滲漏「在最大工作流 量范围内，可以任意调节聚合物溶液的流量,最低不小于1m3/ h,控制压差在1兆岫以内，聚合物溶液黏度保留率大于90% 。
Screening of flowmeters Currently, the flowmeters used in oil fields include turbine flowmeters and electromagnetic flowmeters. Because turbine flowmeters have moving parts in the process, they can shear the polymer and reduce the station degree of the polymer. There are only two electrodes in the process, no moving parts, and no influence on the viscosity of the polymer. Therefore, an electromagnetic flowmeter is used to measure the ground flow (Figure 4).
The ground flow is designed to reduce the viscosity loss of the ground flow, and the ground diversion adopts the principle of proximity. The flow meter and control valve are directly connected to the wellhead, and the pipelines used to connect the process are all nitrided pipelines, and each weld is finely treated to reduce the loss of polymer viscosity.
Concentric double-pipe layered injection polymerization has achieved remarkable results
The concentric double-pipe layered polymer injection process started field trials in April last year. As of the end of September this year, Gudong Oil Production Plant has carried out test applications in 15 wells, and the success rate is 100%. The test proves that this process has better improved the polymer absorption profile of polymer injection wells. The number of layers where the well does not absorb and absorbs the accumulation is reduced from 101 meters in the 21 layers before the measure to 4.5 meters in the first layer. The average injection volume of layers with less accumulation increased from 21.1 cubic meters to 73 cubic meters.
同心双管分层注聚工艺于去年4月开 始进行现场试验。截至今年9月底，孤东 采油厂共在15 口井上进行了试验应用，成功率达100%„试验证明，该工艺较好地改善了注聚井的吸聚剖面。目前，已实施的注聚井不吸聚和吸聚差的层数由措施前21层101米，减少到1层4.5米。措施前吸聚较多的层位平均注入量由112.8立方米下降到74立方米，而吸聚较少的层位平均注入量由21.1立方米上升到73立方米。
The corresponding oil wells have seen better results. Corresponding to 39 oil wells, 37 are comparable, 32 are effective, and the efficiency is 86.5%. The daily oil production increased from 228.5 tons before the measures to 344.0 tons after the measures. The daily oil increased by 115.5 tons, and the cumulative oil increase was 15,100 tons. The number of effective wells after polymer injection increased from 21 before the measure to 33 after the measure, and the effective efficiency increased from 53.8% before the measure to 84.6% after the measure, and the efficiency increased by 30.8%.
The field test shows that the technical indicators of the concentric double-tube layered polymer injection have all met the design requirements, and the double layered layered polymer injection standard with low shear, high pressure difference, high precision and no clogging has been realized, which meets the requirements of isolation. In order to meet the needs of polymer injection and stratification in the East Oilfield, the polymer injection profile has been greatly improved after the implementation, the efficiency of the corresponding oil wells has been greatly improved, and the oil-increasing effect has been obvious.
Relevant experts of Shengli Oilfield believe that the concentric double-pipe layered polymer injection process "revives the second spring of the third production", which is a technological revolution of the third production injection, and this process is worth popularizing in the "three high" oil fields in eastern my country. application.
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Keywords关键词: CCSC Technology, Layered polymer injection technology, innovative three-production technology, layered polymer injection technology, concentric single-pipe layered injection technology, oil-jacketed injection technology, new layered polymer injection technology, process string design.CCSC技术，分层注聚工艺，创新三采技术，分层注聚工艺，同心单管分层注入工艺，油套分注技术，新型分层注聚，工艺管柱设计
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Poster发布人: Clark Guo, CCSC Technology, Shanghai, China, 2022.06 Youtube: Clarkwellhead
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