低饱和度油藏产水率测井预测技术研究

The Method Study of Water-Cut Prediction of Low Oil Saturation Reservoir by Well Logging

摘要: 吐哈盆地台北凹陷低含油饱和度油藏资源丰富，目前已在西山窑组、三工河组发现了低含油饱和度油藏，多口井获得了工业或低产油气流，这种储层的生产特点是油水同出，且能够长期稳产，产水率受油藏含油饱和度控制。利用测井资料准确评价油层饱和度是解决现场生产的关键。本文以红台、温吉桑构造带西山窑组为样本，通过岩心刻度测井，基于岩心物理实验，结合薄片、压汞、核磁实验等资料深入开展储层微观特征研究，建立有效储层的分类标准、评价方法及参数模型。提高了饱和度的计算精度，建立了产水率预测模型和图版，依据产水率的高低，进一步细化油水同层的分类标准，提出完井和试油方案，成果应用于新井解释、老井复查和油藏评价中取得了显著效果，累计新增三级石油地质储量1400多万吨，有效指导了油气勘探与开发。

Abstract: Taibei sag of Tuha basin has rich in petroleum resources in the reservoir with low oil saturation. Oil and gas with commercial value or with low production in many drilled wells have produced from the Xishanyao formation and Sangonghe formation which are the low oil saturation reservoir. The production character of the reservoir is not only a long-term and stable oil production but also water production. Water-cut rate is controlled by the oil saturation. Therefore, accurately evaluate reservoir saturation with well logging data is the key to solve the field production. Currently, the main problem is: to log evaluation of reservoir physical properties and the change of formation water, and oil and water layer difference is not obvious; saturation calculation difficulties; pre-production and production change are big and middle water rate prediction is difficult, unable to effectively guide the production. This study takes Xisanyao formation of Hongtai and Wenjisang structural belt as an example. The method is calibration logging with core, based on the core physical experiment, combined with thin section, mercury injection and NMR experiment etc., to study reservoir microscopic characteristics, to establish effective reservoir classification standard, evaluation method and the model of reservoir parameters. The calculation precision of the saturation is improved. Watercut rate prediction model and chart are established, further refining oil-water classification standard. Well completion and test scheme is put forward. The application in new wells’ evaluation and old wells’ re-evaluation made significant effect, accumulated total of new third-grade oil geological reserves of more than 1400 × 104 tons, and effectively guided the oil and gas exploration and production.