油藏型储气库兼具提高原油采收率及储存天然气两大作用,目前受到了国内外专家的广泛关注.但油藏建库远比气藏建库复杂,国内外针对油藏型储气库渗流特征、相态变化特征、建库可行性等方面的研究较少,严重制约了油藏型储气库的发展.为此,以冀东油田某断块油藏为例,开展多周期注采相渗实验测试、长细管混相压力实验测试,结合油气相态实验与气驱油多周期注采实验,分析明确油藏型储气库建库可行性及建库过程中的渗流规律.研究结果表明:①原油与天然气混相压力为36.2 MPa(高于设计上限压力35 MPa),注采过程中不能发生混相;②注入气溶解能够使原油黏度降低、体积膨胀,经5轮次注采后,天然气抽提能力变弱,原油黏度降低幅度减小,注气改善原油性质的能力略有下降;③经过5轮次油—气和水—气注采后,油和水仍保持较高的渗流能力,但气—油、气—水两相共渗区变窄,渗流能力减弱,气驱油和水效率有一定下降;④相比于水驱,经过5轮次注采后,可提高原油采收率20％,岩心内含气饱和度达到47％.结论认为,多周期注采后能够形成较大库容,且在此基础上能够大幅度提高采收率,该研究成果可为油藏型储气库建设提供技术支持.

低渗透油藏压裂开发中,压裂裂缝的延伸方向、缝高等受现今地应力控制,搞清现今地应力的展布规律即三向主应力方向及数值具有重要意义.南堡凹陷属于复杂断块、陆相小湖盆碎屑岩沉积的地质特点使油藏的岩石力学特性、应力场受到断层、岩性、区域应力场等多因素影响,地应力场描述异常困难.基于岩石力学室内实验,同时参考利用测井数据计算的岩石力学参数,开展地震多属性与力学参数相关性分析,多元回归确定权重,采用确定性和随机建模方法构建三维非均质岩石力学场,实现断陷小湖盆复杂断块油藏三维非均质岩石力学场的构建.在三维非均质力学参数场的基础上,发挥Petrel软件与ANSYS软件在建模和有限元数值模拟上的优势,建立复杂三维地质模型、精细刻画断层并体现储层岩石的非均质性,实现复杂断块三维非均质应力场预测.基于三维非均质地应力场模型,采用全三维有限元法模拟人工裂缝,建立压裂裂缝三维模型,实现复杂断块油藏压后人工裂缝的有效表征.建立基质与人工裂缝耦合的双重介质模型,开展油藏数值模拟研究,明确油藏剩余油分布规律,并针对不同类型剩余油制定不同的挖潜对策.结果表明:发挥Petrel软件与ANSYS软件的优势,精确刻画构造形态,包含断层展布及构造起伏,可实现强非均质砂岩储层的精细表征.

针对注水油藏改建储层库微观渗流机理问题,本次研究首先进行注气速度及储层性质对库容的影响研究,了解多次注气采气循环作业后的渗流特征,最后进行多次注采作业后对库容及渗流能力的影响分析,为推动我国注水油藏改建储气库的进一步发展奠定基础.研究表明:在改建储气库的初期阶段,需要选择一个合理的注气速度,同时还需要考虑形成次气顶以后的强注问题,以此防止气井将油藏内的水资源封隔,增大水锁气的量;对储气库进行多次注采作业以后,其库容和注采能力都会得到一定程度的提升,这十分有利于注水油藏改建储气库.

With distinguishing features of fast phase change,strong aeolotropy,complex hydrocarbon water contact in fan delta,study of remaining oil based on sublayer cannot meet the needs of adjustment during the middle-late development stages,and quantitative description of remaining oil for the single sand body in fan delta reservoir bed was launched.Taking Es33 reservoir in the northern region of Liuzan Oilfield in Nanpu Sag as an example,based on the core description,sedimentary structure analysis,electrofacies recognization,and the method of vertical substage and lateral delimitation,single sand bodies and sandstone boundary were identified.Using the method of fractional facies modeling,three-dimensional anisotropic geologic model for single sand bodies were built.The numerical reservoir simulation for single sand body and three indices including remaining oil saturation,remaining oil reserves abundance and remaining oil reserves are used to quantitatively describe residual oil potential of single sand body.Exploration drilling has confirmed that the forecasting results are helpful and accurate,which can effectively direct the fine tapping of the remaining oil.

南堡凹陷柳赞油田稠油油藏在馆陶组、沙河街组均有分布,属复杂小断块型普通稠油油藏.通过研究原油分析化验资料发现,柳赞油田稠油油藏分布具有明显的区域性和成层性.在详细分析原油地球化学特征的基础上,结合构造演化与油气成藏规律,揭示了区内浅层稠油油藏的形成主要受生物降解与水洗氧化作用影响,深层稠油油藏的形成主要与断层活动有关.

The study of the mineralization degree,water type and ion combination coefficient of the Pre-Tertiary formation water in Chaluhe fault depression,Yitong Basin,reveals that total mineralization degree of the water is relatively low,and NaHCO3 water type,while the formation water has obvious vertical mineralization zonation with a high metamorphic grade.The analysis of the plain and profile of formation water's chemical characteristics not only supplies exact parameters for log interpretation,but also verifies the beneficial zone for oil preservation and potential zone for exploration.

油藏描述技术是综合应用多学科知识,采用先进的计算模块,对储层形态进行精细的描述,对油藏的各种参数进行三维空间的定量描述和表征.油藏描述技术的发展和应用使油藏研究由传统的单一油藏地质研究转入多学科一体化综合的系统研究.不同的勘探开发阶段油藏描述方法具有不同的内容和特点.总结了岩性油气藏、复杂断块油气藏等几种类型油气藏的描述方法,并提出对目前油藏描述方法的认识.

Two methods are selected to evaluate economic re- coverable reserves of Shuangyang formation in Changchun oilfield:Economic Limit Water-cut Method and Cash- flow Method.Based on previous foundation,with the combination of available economic parameters and water- flooding curve,the former method can be developed; while for the second method,besides forecasting the pro- duction and waterflood injection,it also takes running cost,related tax expense,different crude oil prices and other economic parameters into consideration.Therefore, by using these two methods together,the economic recov- erable reserves of Shuangyang formation can he effectively worked out,which provides good guidance for later stage development.