黄16井区氮气-水交替非混相驱先导试验研究

用数值模拟技术对黄16井区的氮气-水交替非混相驱的驱替方式、注气部位、注入方式、注入参数、油井排液量进行了优化,编制了氮气一水交替非混相驱矿场先导试验方案,开展了一个井组的矿场先导试验,总结了先导试验的效果及初步经验     

水气交替方式氮气非混相驱试验研究

江汉油田由于地层水矿化度特别高、区块小，限制了一些三次采油方法的开展。本文通过室内平面模型、长岩心驱油实验研究了地层韵律、注气位置、倾角、水气比等因素对驱替效果的影响，同时优化氮气非混相驱筛选标准，在理论研究基础上选择黄场油田黄16井区开展井组水气交替方式氮气非混相驱先导试验，增油效果显著。     

温吉桑油田水气交替非混相驱研究

吐哈温吉桑油田储集层以正韵律或复合正韵律沉积为主，断层、裂缝不发育。油层少，砂体连通性好。同时，吐哈油区有丰富的天然气资源，这些特征非常适合注气驱，为此开展了注气非混相驱方案研究。通过对注气区块优选 ，注气影响因素分析，注气工程参数优化设计，完成温吉桑油田注天然气水气交替非混相驱方案，形成了套低渗透油田有效实用的水气交替非混相驱注气方案设计方法。方案采用顶部注气，边部注水，水气交替非混相驱方式。水气比为1：1，交替周期半年，累计注入气段塞为0.25倍孔隙体积，提高采收率6%-7%。     

温吉桑低渗油田水气交替非混相驱方案研究

通过对吐哈盆地温吉桑油田注气区块优选，注气影响因素分析，注入气筛选，注气方式、气驱油方式及注水转注气时机的确定，注气工程参数优化设计，水井注气能力、配注气量及井口注气压力的论证，注气井网部署优化，注气方案实施及注气监测工作量部署，完成温五区块、温西一区块、温西三区块注天然气水气交替非混相驱提高采收率方案设计，形成一套低渗透油田有效实用的水气交替非混相驱注气方案设计方法。     

特低渗透油藏CO2混相驱和非混相驱水气交替注采参数优化

以大庆油田贝14区块和树101区块为研究对象,应用油藏数值模拟方法,优化了CO2混相驱和非混相驱水气交替的注采参数.采用经济评价的方法,以经济利润为目标,对CO2水气交替过程中的水气比、注气速度、水气交替时间和水气交替时机4个参数进行了优化研究.结果表明,对于CO2混相驱,气油比达到50 m3/t时开始水气交替,水气比...     

水驱后特低渗透油藏氮气驱驱油特性分析

特低渗透油藏水驱采收率低,注入压力高,而氮气在特低渗油藏具有良好的注入性。本文在特低渗透岩心水驱后分别进行了常规的注氮气、水驱后水气交替、水驱后脉冲注氮气驱替实验。实验结果表明:特低渗储层微观非均质性导致气体在大孔道易形成窜流,水驱后常规注氮气提高采收率的效果有限。水气交替通过多轮次的注入使油藏中不同相态流体的分散程度提高,在优势流动通道中形成毛管阻力,促使后续注入气体进入局部致密区,可有效提高采收率16.37%;脉冲注气通过周期性注气方式,在局部高渗区和局部低渗区间形成压力扰动与交互渗流,使流体在地层中不断地重新分布,从而启动油层低渗区原油,提高采收率15.94%。此外,脉冲注气的注气压力比较低,与水气交替开采方式比较注入性提高。图6表1参12     

断块油田不同方式注氮气的研究与实践

断块油田水驱开发后期都面临高含水的问题,如何降低含水提高油藏采收率一直是研究重点。着重在通过氦气对地层由膨胀降粘及长岩心水气交替物模实验基础上介绍了注氮气降水增油机理和在现河断块油田采用氮气吞吐、气水交替驱以及泡沫驱等不同注入方式下的矿场实践情况,分析了影响注气效果的因素,为断块油田注氮气提供一些经验。     

冀东油田高13断块注烃气驱提高采收率优化研究

冀东油田高13断块油藏渗透率低,水驱开发效果差。但油藏温度和压力较高,原油粘度小,适宜注烃气驱提高原油采收率。针对高13断块油藏,在流体相态拟合的基础上,应用油藏数值模拟技术进行了注烃气驱提高采收率方案优化研究。研究结果表明,气水交替驱是最佳的注入方式。优化后的气水交替驱注采参数为：最佳的注气段塞大小为0．3HCPV,气水比为1：1～1：2,注入速度为0．03～0．04HCPV／a,注采比为1．0～1．1,优化方案与水驱方案相比提高采收率9．7％。     

裂缝性油藏水气交注非混相驱实验研究

为解决低渗裂缝性油藏在注水开发中出现含水率急剧上升的问题,开展水-气交注非混相驱室内实验研究。分析注入方式、气液比、温度等因素对采收率的影响。实验结果表明,氮气驱＋水-氮气交替注入段塞效果最好。气液比为1∶1-3∶1时,随着气液比增大,最终驱油效率明显提高;温度对水、氮气交注非混相驱的驱油效率有一定影响,但不明显。该研究具有较好应用、推广价值。     

茨34块CO2驱参数优化与方案设计

茨 34 块在目前注水开发的过程中存在的着油水流度比大,油层压力下降快,油层能量低,地层亏空严重等一系列问题.为了进一步提高茨 34 块的开发效果,进行了普通稠油注 CO2 驱数值模拟研究,优化了注入周期、注入压力、注入气水比、油井排液量等参数,预测了最佳开采方案.数值模拟研究表明,保持现有注采井网进行注水开发,到 2011 年茨 34 块累积产油量为 308 961 t;茨 34 块注气方式为气-水交替注入,注气周期为 60 d,单井注入量为目前注水量的 2.0倍,气水比为 1.0:2.0,油井排液量为目前日产液酌 1.0 倍时,开采效果最佳;在现场注气试验中注气量选用 1 200 t 时最好.     

葡北油田气水交替驱提高采收率矿场试验研究

吐哈盆地葡北油田是我国第一个气水交替驱矿场试验基地,开发方式为气水交替注入混相驱开发。为解决葡北油田气水交替注入过程中无法实施注水转注气的实际问题,通过室内长岩心驱替实验,进行了注气机理、现场酸化解堵、高压注液氮、注入井关井降压等多项研究,解决了注入井气水切换的问题。葡北油田实施混相驱开发以来,地层压力和流压保持水平均在混相驱开发确定的压力界限以上,地层流体黏度由原始的0.67mPa·s降为目前的0.20mPa·s,体积系数由2.210增大为2.819,饱和压力由29.44MPa上升为目前的32.86MPa,原油组分变化明显,中间烃含量由23.79％上升至25.12％,证明葡北油田实现混相驱开发,开发效果较好。图2表2参9     

The Experimental Investigation of Nitrogen and Carbon Dioxide Water-alternating-gas Injection in a Carbonate Reservoir

Abstract

Floods were conducted using rock–fluid systems consisting of carbonate cores from Binak reservoir, which is located in southwest of Iran, oil and brine. The coreflood protocol consisted of a series of steps including brine saturation, absolute permeability determination, flooding with oil to initial oil saturation, endpoint oil permeability determination, and, finally, nitrogen and carbon dioxide water-alternating-gas (WAG) injections. The effect of slug size on oil recovery was investigated using immiscible nitrogen (N₂) WAG injection and the amount of oil recovered was compared with continuous injection of N₂. Experimental results show that ultimate oil recovery is not very sensitive to changing the slug sizes for N₂ WAG injection, although the slug size of 0.15 pore volume (PV) injection is better than others. As less PV is injected, a higher oil production rate is achieved. Also, N₂ WAG flood appeared to be better in performance than continuous gas injection (CGI) of nitrogen. Carbon dioxide (CO₂) injection was performed in three modes, including CGI, WAG injection, and hybrid WAG. Experimental results show that for optimization of oil recovery in CO₂ floods, a continuous gas slug of 0.4–0.5 PV followed by 1:1 WAG needs to be injected.     

Maximizing the Oil Recovery Through Miscible Water Alternating Gas (WAG) Injection in an Iranian Oil Reservoir

In recent years there has been an increasing interest in water alternating gas (WAG) processes, both miscible and immiscible. Microscopic oil displacement and sweep efficiency of waterflooding and continuous gas injection can be improved by WAG injection. In this work, by designing various scenarios of water and gas injection, WAG injection and simultaneously water and gas injection, the recovery and residual oil saturation obtained by implementing these methods are compared to choose the appropriate method of injection. The results showed that simultaneously the water and gas injection method has the highest recovery but from economic view, WAG process is the best enhanced oil recovery method to increase the recovery. In WAG method, the values of gas oil ratio and water cut are the smallest, so in this case, operational and process facilities problems and their costs are the minimum.     

An Experimental Study on the Applicability of Water-alternating-CO2 Injection in the Secondary and Tertiary Recovery in One Iranian Reservoir

Abstract

The objective of this study was to experimentally investigate the performance of water-alternating gas (WAG) injection in one of Iran's oil reservoirs that encountered a severe pressure drop in recent years. Because one of the most appropriate studies to evaluate the reservoir occurs generally on rock cores taken from the reservoir, core samples drilled out of the reservoir's rock matrix were used for alternating injection of water and gas. In the experiments, the fluid system consisted of reservoir dead oil, live oil, CO₂, and synthetic brine; the porous media were a number of carbonate cores chosen from the oilfield from which the oil samples had been taken. All coreflood experiments were conducted using live (recombined) oil at 1,700 psi and reservoir temperature of 115°F. A total of four displacement experiments were performed in the core, including two experiments on secondary WAG injection and others on the tertiary water and gas invaded zones WAG injections. Prior to each test porosity and permeability of dried cores were calculated then 100% water-saturated cores were oil-flooded to obtain connate water saturation. Therefore, all coreflooding tests started with the samples at irreducible water saturation. Parameters such as oil recovery factor, water cut, and gas-oil ratio and production pressure of the core were recorded for each test. The most similar experimental work with the main reservoir condition, indicated that approximately 64% oil were recovered after 1 pore volume of WAG process at 136,000 ppm brine salinity. Although tests show ultimate recovery of 79% and 55% for secondary and tertiary injection in gas and water invaded zones, respectively, immiscible WAG injection efficiency in the gas and water invaded zones will not be proper. In the similar test to field properties, the average pressure difference about 70 Psig was observed, which shows stable front displacement. These experiments showed that there was significant improvement in the oil recovery for alternating injection of water and CO₂, especially in the secondary recovery process. Water breakthrough time in almost all of the tests shows frontal displacement of injected fluid in cores and produced gas-oil ratio changes a little whenever the injection is miscible and increases rapidly in immiscible processes.     

温西3块非混相驱注气参数优选室内实验研究

开展温西3块非混相驱长岩心室内实验,分析了注入气贫富、注入气段塞尺寸、注入气水比和转注气驱时机对驱油效率的影响,并优选出了该块非混相驱注气参数.该项研究对今后类似油藏的开发具有一定的借鉴作用.     

肇源油田高温混合气驱油物理模拟实验研究

针对肇源油田常规开发效果差的特点,开展了高温混合气驱油物理模拟实验。采用基础管式物理模拟试验装置,分别进行了不同气汽比对比、不同大小注气段塞对比、不同温度以及地层温度注气与气水同注的高温混合气驱油室内实验。结果表明,随着混合气温度的提高,驱油效率增加,气汽比为1∶1、采用段塞驱、烟道气与水蒸汽复合同注时,驱油效果最好。     

The Evaluation of Variable-Injection Rate Waterflooding,Immiscible CO2 Flooding,and Water-alternating-CO2 Injection for Heavy Oil Recovery

Abstract

Despite the existence of studies for separate evaluation of waterflooding, immiscible CO₂ flooding, and CO₂ water-alternating gas (WAG) for heavy oil recovery, there is a lack of an experimental, comparative evaluation of these three methods. The authors conducted tests for comparative evaluation of variable-injection rate waterflood (VIWF), immiscible CO₂ flood, and CO₂ WAG. The results illustrate the (a) effectiveness of VIWF, immiscible CO₂ flood, and CO₂ WAG; (b) effect of permeability and oil viscosity on VIWF, immiscible CO₂ flood, and CO₂ WAG; (c) effect of injection rate on VIWF; and (d) effect of slug ratio on CO₂ WAG.     

裂缝性底水潜山油藏注气数值模拟研究

碳酸盐岩存在裂缝发育,先期水驱时,裂缝的高导流能力致使注入水充满了大部分裂缝,高含水与高效开发产生了深刻的矛盾。注气能够保持地层压力,波及效率较水驱高。为评价CO2的驱油效果,用正五点法单元井网,应用数值模拟软件,对华北任丘裂缝性底水潜山油藏CO2驱注气参数进行优化,主要包括段塞大小优化、注气速度优化、气水交替中的小段...     

Recovery Improvement Using Water and Gas Injection Scenarios

Abstract

Water and miscible gas injection scenarios are considered in an Iranian oil reservoir for the purpose of recovery improvement. Firstly reservoir fluid modeling and modeling of a slim tube test were performed. Then, water alternating gas (WAG) injection was evaluated by optimizing the WAG half cycle and WAG ratio. Alternatively, hybrid WAG and separate injection of water and gas in the top and bottom of the reservoir were also investigated. The numerical simulation results showed that the optimum WAG, with half cycle of 1.5 years and WAG ratio of one, gave the highest recovery factor. Moreover, economic evaluation of these scenarios indicated that WAG had the highest net present value and was the most interesting scenario for improving the recoveries.     

QK17-2油田注N2-WAG提高采收率可行性实验研究

气水交替驱(WAG)是增加油田水驱后的波及体积和减弱气驱过程因油气黏度差异而产生的气体指进现象的有效方法。QK17-2油田为注水开发油田,目前油田综合含水率已超过80%,已经进入开发中后期的高含水时期。针对QK17-2油田水驱后面临高含水、产油量下降的问题,通过地层流体相态实验、注N2膨胀实验、细管实验、长岩心驱替实验,研究注水后再注N2-WAG可进一步提高采收率的可行性。结果表明,单纯注N2效果不佳,注N2-WAG采收率较单纯水驱采收率提高4.46%~6.24%,而长岩心驱替在带倾角条件下注N2-WAG采收率较单纯水驱提高11%~12.58%,可见由油藏高点注N2-WAG采收率将有明显提高。