A dual-porosity dual-permeability model for acid gas injection process evaluation in hydrogen-carbonate reservoirs

The Pre-Caspian basin is one of the most prolific in terms of oil and gas exploration and hydrogen and carbon compounds energy production around the world. The major hydrogen and carbon compounds reservoirs are Carboniferous reef and platform hydrogen-carbonate rocks. The original fluids under subsurface conditions contain 15% hydrogen sulfide and 4% carbon dioxide. Acid hydrogen and carbon compounds reinjection is not only an environmentally friendly solution for disposal of produced greenhouse gases but also enhances oil recovery and supplies more fuel energy. On the other hand, the presence of fractures makes hydrogen-carbonate reservoir characteristics nature more complicated than conventional sandstone reservoirs, which leads to a tremendous challenge to evaluate the gas injection process. In this work, a dual-porosity dual-permeability formulation was used to model the dual-medium nature incorporating matrix system with high porosity and low permeability and fracture network with low porosity and high permeability. After matching PVT experiments, a ten pseudo-components fluid model was generated for running compositional simulation. The miscible hydrogen and carbon compounds injection was simulated as an effective enhanced oil recovery approach. Sensitivity analysis such as timing of injection gas, injection rate, well spacing and completion interval have proposed the optimal condition for the miscible hydrogen and carbon compounds flooding. The recommended optimum hydrogen and carbon compounds injection scenario is twice higher oil recovery compared with natural depletion. The results of this study illustrate further the practicability of pseudo-components splitting and lumping for compositional simulation to evaluate the performance of hydrogen and carbon compounds injection processes, and are of great importance using the dual-porosity dual-permeability method performing numerical simulation of naturally fractured hydrogen-carbonate reservoirs.     

GO7-23-5206井组凝胶调剖设计及效果分析

井间动态连通性是油藏动态分析的重要内容之一。孤东七区具有高孔高渗、强非均质、储层结构疏松、易出砂的特征。由于孤东油田水驱不均匀,使注入水在平面上形成水驱水流优势通道,从而有可能降低水的扫驱效率。针对这一严峻形势,先用流管图模拟出大孔道以及具有注采对应关系的注水井组。为后期调剖,选井选层提供重要的依据。并且通过连通性分析可以判别水流优势通道分布,最终达到提高采收率的目的。系统开展窜流通道定量化调剖技术提高采收率的研究。选定了一个具有代表性的典型注水井组,以凝胶为调剖剂,利用CMG软件,通过对凝胶的注入量和注入时间,从而确定注入速度,最后根据投入产出比,优选出最合适的方案,并在现场实施中获得良好的效果。     

悬浮凝胶颗粒调驱剂研究与现场试验

针对辽河油田注水区块现有颗粒类深部调驱堵剂耐温、抗剪切性能差,成胶强度低,有效期短,压力提升幅度有限等问题,采用丙烯酰胺与天然橡胶胶乳、乙烯基吡咯烷酮通过自由基共聚,经胶体干燥、造粒得到具有良好柔韧性和粘弹性能的柔性凝胶颗粒,并确定了最佳聚合反应条件:单体浓度30%,丙烯酰胺:天然橡胶胶乳:乙烯基吡咯烷酮质量比为1:0.8:0.3,交联剂浓度0.05%,引发剂(甲醛合次硫酸氢钠与过硫酸铵质量比为1:2)浓度0.6%,聚合反应温度65℃。同时确定了用于悬浮凝胶颗粒的凝胶配方体系:聚合物800 mg/L、交联剂400 mg/L、稳定剂80 mg/L,得到了凝胶颗粒现场应用的合理粒径中值为2 mm,最佳使用浓度范围1%~3%。现场试验结果表明:凝胶颗粒对调驱压力提升作用明显,具有很高的可行性和实用性,为注水区块稳油控水提供了有力的技术保障。     

臭氧氧化法分解聚驱采油废水中水解聚丙烯酰胺的过程分析

对含水解聚丙烯酰胺(HPAM)的模拟废水分别采用单独臭氧氧化和电絮凝耦合臭氧氧化两种方法进行处理。考察处理方法对HPAM降解的影响,采用GC-MS和FTIR方法对HPAM降解物进行表征以分析HPAM降解的过程。实验结果表明,单独臭氧氧化处理模拟废水时,在臭氧用量4.2 mg/L、废水pH=10、反应120 min的条件下,COD和HPAM的去除率分别为37.1%和83.4%;电絮凝耦合臭氧氧化处理模拟废水时,经电絮凝30 min后,再臭氧氧化120 min,COD和HPAM的去除率分别为82.2%和94.4%。臭氧氧化降解HPAM的过程可推断为:HPAM分子经断链分解为低相对分子质量的聚合物,低相对分子质量的聚合物继续氧化生成丙烯酸和丙烯酰胺的中间体,中间体再进一步氧化为烷烃、醛酮类、酯类等物质,最终彻底矿化。     

Verification and validation of explicit moving particle simulation method for application to internal flooding analysis in nuclear reactor building

The Fukushima nuclear accident raised the importance of flooding study in nuclear reactor buildings. It is known that the external flooding can be attributed to natural causes, while the internal flooding is caused by the piping ruptures, tank failure or the actuation of fire suppression systems. The building flooding process can damage the safety-related components and systems, which needs to study carefully. In order to simulate this phenomenon which is accompanied by complex flow with free surface, a particle method based on Lagrangian approach named explicit moving particle simulation (EMPS) method, is employed in this analysis. Verification and validation analyses are carried out. The verification problems are a hydrostatic analysis and a water spreading to investigate the differences of the particle wall and polygon wall boundary models, while the validation studies of two experiments of dam-break induced flooding show good agreements. Afterwards, the internal flooding process in AP1000 is simulated by assuming a break of the in-containment refueling water storage tank as an example. The results achieved so far indicate that the EMPS method is capable to simulate the internal flooding process in the nuclear reactor buildings.     

煤田巷道防水侵水泥浆材的封堵试验

井下巷道掘进仍然是地下煤炭开采的主要方式,在开采过程中必然要穿过一些断裂地层带以及无胶结的松软地层及煤层顶板上的含水层。在掘进过程中,如果处理不当,地层中的水将沿着裂缝和采空塌陷区大量进入巷道内,造成严重的透水事故,使掘进工作无法顺利进行,严重时将导致井巷的报废,甚至造成重大的人身伤亡事故。针对传统水泥浆经水侵后不凝固或被流动水稀释而完全漏失,起不到应有的封堵固化作用等问题,研制出一种防水侵水泥浆封堵材料。该水泥浆与水按1∶1的比例掺混后仍具有凝结时间快、凝结强度高等特点,可在25℃以上的温度条件下使用。在某煤矿840 m井深、120 m3/h出水量情况下进行堵水作业试验,堵水效果良好,可在类似的条件下推广应用。     

特高含水油藏CO_2气水交替驱注入参数优化方法

影响CO2气水交替驱开发效果的参数较多,为了得到最佳开发效果,以特高含水开发阶段的A井组为研究对象,运用数值模拟方法,对该井组CO2气水交替驱注入参数进行了优化,建立了一套CO2气水交替驱、提高采收率注入参数优化的思路和方法。结果表明:实施CO2气水交替驱能使高含水井含水率下降5~10个百分点,增加产油,并保持地层压力稳定,维持油井长时间经济有效生产。     

强碱三元复合驱开采动态特点

以4个强碱三元复合驱工业性试验区为研究对象,研究了注采能力、综合含水率、采油速度、油层动用状况、采出化学剂变化以及结垢与乳化规律,将三元复合驱全过程划分为5个阶段.结果表明:注采能力在前置聚合物段塞大幅度下降,整体水平略低于相近地质条件的聚合物驱;油层动用程度明显增加,含水率下降幅度高于聚合物驱,采油速度是聚驱的2倍左右;采出化学剂顺序是聚合物、碱、表面活性剂;三元主段塞后期开始结垢,随着pH值的升高,由碳酸盐垢变为与硅垢的混合垢,保护段塞以后结垢减轻;含水率进入低值期采油井开始乳化,主段塞阶段随含水率升高乳化类型由油包水型转变为水包油型,副段塞阶段为水包油型乳化.