高集油田剩余油影响因素及其分布研究

The Influential Factors and Distribution of Remaining Oil in Gaoji Oilfield

高集油田已进入中高含水阶段,油藏历经多年的注水开发,剩余油分布趋于复杂,因此对剩余油影响因素及其分布的研究就显得尤为重要。研究表明,储层内的沉积韵律与夹层、单砂体内韵律性、沉积结构和沉积相变导致的垂向上储层性质变化,夹层的发育特征是控制单砂层垂向上注入水波及体积和层内剩余油形成及分布的主要地质因素。通过分析发现,不同的韵律类型、隔夹层、沉积微相与油砂体的空间组合可以产生不同的剩余油分布模式。无论是在垂向上还是平面上,在夹层频率较高部位、正韵律顶部、反韵律底部、物性较差的相带,其渗流率都较低,从而形成了渗流屏障,使油气不易被驱替,形成了剩余油的富集区。

Gaoji Oilfield has entered into the stage of mid-high water cut of oil exploitation,where remaining oil distribution tended to be complex,thus the study on the influential factors and distribution of remaining oil was especially important.Research showed that sedimentary rhythm and interlayer in reservoir,rhythm and sedimentary structure in single sand body,sedimentary facies changes induced vertical changes in reservoir properties and development characteristics of interlayer were the main geological factors controlling the vertical sweep volume of injected water,the formation and distribution of remaining oil within the single sand layer.In addition,the development factors have a certaininfluence on the distribution of remaining oil.It is found out in analysis that the space combination of different types of rhythm,interlayers,sedimentary micro-facies and oil sand body can produce different patterns of remaining oil distribution.Whether it is distributed vertically or on the plane,the places of high frequency interlayer,the top of positive rhythm,the bottom of reverse rhythm and poor petrophysical facies are low seepage rate.Thus a seepage barrier is formed,where oil and gas are not easy displaced and a remaining oil enriched region is formed.