低渗透油藏氮气泡沫驱油实验研究

发布时间：2018-03-14 07:12

本文选题：低渗透　切入点：非均质　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：新疆X油藏属于低孔、低渗及强非均质油藏,这类油藏在注水过程中层间矛盾显著,储层动用不均,注入水在高渗透层中窜流严重导致含水上升加快,低渗透层动用程度差,剩余油储量大。针对X油藏开展了氮气泡沫驱油实验研究,通过氮气泡沫的调驱作用进一步提高采收率。本文研究形成了适合X油藏的氮气泡沫驱油体系;分析了体系液相黏度、起泡剂吸附性能、压力以及原油对泡沫稳定性的影响;研究了氮气泡沫在低渗均质岩心、并联非均质岩心以及三并联非均质岩心中的驱油特性。取得的主要认识如下:(1)0.25%Y1起泡剂体系在油藏条件下(温度73℃、矿化度24818.5 mg/L)老化90d后起泡体积为554mL,析液半衰期为162s,仍具有良好的起泡性和稳定性。聚合物P4可有效延长泡沫析液半衰期,泡沫析液半衰期随聚合物浓度增加而增加且二者近似满足线性关系。0.25%Y1+0.2%P4体系老化90d后,其泡沫析液半衰期为946s,具有良好的稳定性。(2)对于强化起泡体系,影响泡沫稳定性的主控因素在于黏度,而不在于界面张力和表面张力。高压有利于提高泡沫的稳定性。X油藏轻质原油对普通泡沫和强化泡沫体系的起泡性能无显著影响,起泡体系中加入聚合物有利于提高含油泡沫的相对稳定性。(3)均质单岩心普通氮气驱油实验表明,气液比、氮气泡沫注入速度、氮气泡沫注入量以及泡沫注入时机均对泡沫驱油有影响:①气液比和泡沫注入速度均存在一个合理值使得在注泡沫和后续注水过程中氮气泡沫驱具有最佳的驱油效率;②氮气泡沫驱提高驱油效率值随泡沫注入量的增加而增加,当泡沫注入量大于0.5PV后,驱油效率增加缓慢;③在实验注入时机范围内(含水率为71.43%-98.32%),注入时机提前有利于提高驱油效率。(4)水驱和氮气泡沫驱速度均为5.94m/d时,通过双并联非均质岩心泡沫驱油实验可得出:①水驱可启动渗透率级差为5.22的低渗岩心,而无法启动级差为7.20的低渗岩心;②普通氮气泡沫能在渗透率级差为10.67的并联岩心中建立良好的流度控制能力,降低高渗岩心分流率,增加低渗岩心分流率,能够有效增加高渗岩心以及低渗岩心的驱油效率,而不能启动渗透率级差为15.46的低渗岩心;③强化氮气泡沫能有效启动渗透率级差为15.68的低渗岩心;④随着注入时机的提前,普通氮气泡沫对渗透率级差为10左右的低渗岩心的动用程度逐渐减弱,泡沫注入时机为含水率76.69%时,低渗透岩心无法动用。(5)对于渗透率变异系数为0.28和0.72的三并联非均质岩心,水驱只能启动前者的低渗岩心而不能启动后者的低渗岩心,普通氮气泡沫驱可有效动用后者的低渗岩心,且氮气泡沫驱对渗透率变异系数大的三并联非均质岩心的驱油效果较差。本文在低渗透、强非均质油藏注氮气泡沫方面取得的认识,将有利于丰富氮气泡沫驱的应用范围;同时,对于氮气泡沫提高采收率技术的矿场应用也具有实际意义。
[Abstract]:Xinjiang X reservoir is low porosity, low permeability and strong heterogeneity reservoir, the reservoir in the water interlayer contradiction significant reservoir producing uneven water injection in high permeability layer resulted in serious channeling water rises up, the producing degree of low permeability reservoirs, the remaining oil reserves for X oil reservoir. The nitrogen foam flooding experiments, further enhance oil recovery by nitrogen foam flooding. This paper studies the formation of the oil displacement system for X reservoir of nitrogen foam; analysis of the system of liquid viscosity, foaming agent and oil absorption performance, pressure effect on foam stability; study of nitrogen foam in low permeability homogeneous the core, heterogeneous core and three parallel heterogeneous rock displacement characteristics in parallel. The main conclusions are as follows: (1) 0.25%Y1 foaming agent system under reservoir conditions (temperature of 73 DEG C, the mineralization degree of 24818.5 mg/L) after aging for 90d foaming volume is 5 54mL, the drainage half-life of 162s, still has good foamability and stability. Polymer P4 can effectively prolong the half-life of foam drainage, foam drainage half-life increases with the polymer concentration increases linearly and the two.0.25%Y1+0.2%P4 system after 90d aging, the foam drainage half-life of 946s, has good stability. (2) to strengthen the foaming system, main controlling factors affecting the stability of foam is not in viscosity, interfacial tension and surface tension. High pressure is beneficial to improve the stability of foam.X light crude oil reservoir on foaming property of common foam and strong foam system has no significant effect, adding polymer foaming system to improve the relative stability of the oil bubble. (3) homogeneous core common nitrogen flooding experiments, gas-liquid ratio, nitrogen foam injection rate, injection volume of nitrogen foam and foam injection timing on Foam flooding effect: gas-liquid ratio and foam injection rate has a reasonable value in the bubble and subsequent injection in the process of water flooding efficiency of nitrogen foam flooding is the best; the nitrogen foam flooding can increase the oil displacement efficiency with the increase of foam injection volume increases, when the bubble injection amount is greater than 0.5PV. A slow increase oil displacement efficiency; in the experiment of injection time range (moisture content 71.43%-98.32%), injection timing advance can improve the oil displacement efficiency. (4) water flooding and foam flooding velocity was 5.94m/d, the double parallel heterogeneous core foam flooding experiment showed: water flooding can be started permeability for low permeability core 5.22, did not start the reason for low permeability core 7.20; the general nitrogen foam can establish good mobility control ability for parallel cores in 10.67 lower permeability, high permeability core flow rate increased. Low permeability core flow rate, can effectively increase the high permeability core and low permeability core oil displacement efficiency, which can not start permeability for low permeability core 15.46; the enhancement of nitrogen foam can effectively initiate permeability for low permeability core 15.68; with the injection timing advance, ordinary nitrogen foam on the permeability ratio is about 10 the producing degree of low permeability cores is gradually weakened, foam injection time for moisture content is 76.69%, low permeability cores can be used. (5) the permeability variation coefficient is 0.28 and 0.72 of the three parallel heterogeneous cores, water flooding can only start the low permeability core and low permeability core which can not be started, ordinary nitrogen foam flooding can effectively use the low permeability core, and nitrogen foam flooding for three parallel permeability variation coefficient of the heterogeneous core flooding effect is poor. In this paper, low permeability, strong heterogeneous reservoir of nitrogen injection The understanding of bubble foam will help to enrich the application scope of nitrogen foam flooding, and at the same time, it has practical significance for the field application of nitrogen foam enhanced oil recovery technology.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.46

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