【作者】 高树生；

【导师】 于兴河；

【作者基本信息】 中国地质大学（北京） ， 油气田开发工程， 2012， 博士

【摘要】 新疆莫北油田2010年预计可新增千万吨级规模储量、新建产能近百万吨,成为新疆油田近年来在老油田深化滚动勘探探明的最大整装稀油油藏。莫北油田老井开发过程中普遍存在水驱机理不清、无水采油期短、见水后产能急速下降、最终采收率低等问题。为保障莫北油田重点区块莫116井区开发方案的编制与高效开发,本文以渗流理论为基础,运用恒速压汞、核磁共振、高精多功能渗流平台等物理模拟与数值理论模拟计算两项关键技术,研究了砂砾岩储层的物性特征、渗流机理、有效驱替理论、井网井距,并进行了老区生产动态分析。主要成果如下：(1)系统地评价了砂砾岩储层的物性特征,论证了主流喉道半径、可动流体饱和度、拟启动压力梯度是表征低渗砂砾岩储层物性的关键参数,其与储层岩性具有很好的对应关系。(2)研究了储层的微观孔隙结构特征及其分布规律,发现储层喉道大小及其分布规律是储层渗流能力和开发效果的控制性因素,首次基于微观结构特征建立了可用于水驱开发动态预测的渗流理论模型。(3)揭示了莫116井区砂砾岩储层相对于其它渗透率相近的砂岩储层主流喉道半径较大、启动压力梯度较小、微观非均质性更强的特点是莫北油田注水难度较小,水驱油效率低的本质原因。(4)明确了莫116井区储层存在较弱的速敏与压敏及中等偏强水敏的敏感性特征；储层的束缚水饱和度较高,油水两相共渗区间窄,仅为20%,无水采出程度占最终采收率的85%以上,见水后含水率迅速上升到90%以上；具有一定的渗吸采油能力等一系列渗流特征。(5)推导了基于等值渗流理论并考虑启动压力梯度的两相三区水驱油渗流模型,论证了注水有效性的影响因素,编制了多因素的井网井距图版和注水有效性理论图版。应用上述成果并结合老区生产动态分析,揭示了砂砾岩储层水驱开发的固有特征,明确了莫116井区砂砾岩储层水驱开发动态机理及提高莫116井区油藏最终采收率的两个关键：一是通过井网、井距和生产制度优化来延长无水采油期,以提高无水期采出程度；二是在水驱后期,通过调剖等手段来改善吸水剖面,提高波及体积,以提高水驱后期的采出程度,从而达到提高莫北砂砾岩油藏最终采收率的目的。更多还原

【Abstract】 It has been predicted that more than ten millions reserves was found in Mobei oilfield of Xinjiang in October,2010, about millions of which would be developed. And dute to that, Mobei oilfield has became one of the biggest of large piece thin reservoir with the development of rolling mode for the past few years. But the problems, such as, misunderstanding of the waterflooding mechanism, shortness of water free production period, deliverability descend hasty when water breakthrough, the low final recovery efficiency and so on, were widespread in the process of development of the old oilfield blocks. In order to insure the compilation of the development plan and the efficient development of Mo 116 well field, some critical technologies, including constant speed mercury injection, NMR, Multi-functional seepage platform and numerical simulation calculation, were applied to study physical characteristic of sand-conglomerate reservoir, percolation mechanism, effective displacement theory and pattern well spacing and so on. We also evaluated the performance of old oil field blocks. Main results are as follows:(1) It has been evaluated systematacially the properties of sand-conglomerate reservoir and demonstrated that the parameters of microscopic pore structure characteristics, mobile fluid saturation and trigger pressure gradient have the very good corresponding relation with reservoirs lithologies.(2) We also found out the characteristics of micro pore structure of Mobei oilfield. And we thought that the size and distribution of the throats was critical factor to determine the flowing capacity and development of the reservoir. Base on of micro pore structure, we have built flowing theory model, which could predict the reservoir production dynamic performance.(3) Compared with other low permeability reservoir, the reason why it’s easy to inject water and the water displacement efficiency is low in Mo 116 well field is that the mainstream throat radius of Mobei field is wider, the trigger pressure gradient is lower and the microscopic heterogeneity is more serious.(4) The reservoir of Mobei field has some degree of sensitivity, including weak speed sensitivity, weak pressure sensitivity and medium water sensitivity. There has been high bound water saturation and its common seepage interval is very narrow, only 20%. Althought breakthrough recovery reach up to about 85%, it’s hard to increase production when water breakthrough because water content will rise to 90% quickly. In the process of development, there exists some degree ability of imbibition oil recovery.(5) Base on the equivalent seepage theory, we have obtained the model of three districts, two-phase theory of seepage of water flooding which considered the trigger pressure gradient. We also demonstrated the influencing factors of water injectiom effectiveness, and gave theoretical chart boards about rationale well nets spacing and effective water injection.Applying the above results to actual oilfield development, there are two ways to improve the final recovery efficiency of Mo 116 well field. The first one is to optimise well network, well spacing and production system to prolong the water free recovery. The second one is to ameliorate water-injecting profile in the later stage of waterflooding, which could improve spread coefficient and brought higher recovery efficiency.更多还原