姬塬油田长8油藏注水井欠注主控因素

姬塬油田长8油藏具有欠注井数多、欠注程度高、形成原因复杂等问题,造成地层能量低和油井递减快,目前已成为制约油井稳产的重要因素之一。针对这一问题,从地质因素和开发因素出发,系统分析了储层渗透率、储层微观特征、敏感性、润湿性、注入水水质和水型配伍性等对注水井欠注的影响,在此基础上,建立了主成分分析(PCA)和最大隶属度相结合的欠注主控因素判别方法,以油田133组欠注井数据为样本,求取了24项关键特征参数的影响权重,发现储层物性、注入水水质和水型配伍性是对姬塬油田欠注影响最为显著的因素;实例应用表明,该方法能够定量、准确地判别注水井的欠注主控因素,为后续有针对性地制定治理措施提供依据。

Research on the main controlling factors of the under-injection wells in Chang 8 reservoirs of Jiyuan Oilfield

The Chang 8 reservoir in Jiyuan Oilfield exist a large number of under-injected wells, most of which are with high under-injection degrees and complicated influence factors, this result in low formation energy and fast decline of oil productions. In order to solve this problem, based on geological and development factors, systematical analyzes on the reservoir permeability, reservoir microscopic characteristics, sensitivity, wettability, injection water quality and water compatibility are conducted to illuminate the influences on the under-injection wells; then, the PCA (principal component analysis) and the maximum membership degree methods are combined to establish the main controlling factors of the under-injection discriminant method, with 133 groups of data from Jiyuan Oilfield taken as samples, the influence weight of 24 key characteristic parameters are determined. It is found that the reservoir physical property, injection water quality and water compatibility are the most significant influential factors to lead the under-injection problems of Jiyuan Oilfield. The application shows that this method can identify the main control factors of under-injection quantitatively and accurately, and it can provide a reliable guidance for the subsequent treatments of the under-injected wells.