低渗稠油油藏CO2表面活性剂复合吞吐开发——以克拉玛依油田五区南上乌尔禾组油藏为例

克拉玛依油田五区南上乌尔禾组油藏为低孔低渗稠油油藏,储集层物性差,注水开发产量递减快,地层能量保持程度低,后油井全面关停。近年来重新压裂复产,初期效果显著,但产量递减率高。为解决油井低产低效的问题,开展CO₂表面活性剂复合吞吐技术研究,并进行提产试验。在增油机理实验的基础上,应用多组分油藏数值模拟技术,对CO₂表面活性剂复合注入方式及参数进行优化;建立了增产油量随不同吞吐周期注入量、注气速度、焖井时间、开采强度等参数变化的响应关系,确定了复合吞吐的最佳注入参数。矿场实施后,单井自喷达240 d,增产原油630 t,补充地层能量、改善流动性的效果显著,可供同类油藏开发参考。

Development of Low-Permeability Heavy Oil Reservoirs by CO2 + Surfactant Combination Huff and Puff : A Case Study of Upper Wuerhe Formation Reservoir in Southern Block 5, Karamay Oilfield

The reservoir in the upper Wuerhe formation, southern Block 5, Karamay oilfield, is a heavy oil reservoir with low porosity and low permeability, indicating poor reservoir physical properties. When it was developed by water injection, the production decreased rapidly, and the formation energy kept low; as a result, all production wells were shut in or suspended. In recent years, some wells have been refractured to resume production and good effects have been gained in the initial stage, but the production declines rapidly. In order to solve the problems of low production and low efficiency of production wells, the CO₂ + surfactant combination huff and puff technology was developed and tested for production enhancement. On the basis of experiment on stimulation mechanism, through multi-component reservoir numerical simulation, the method and parameters for injecting CO₂ + surfactant were optimized. The relationship between the changes of the production increment and the parameters such as injection volume, injection rate, soaking period and production intensity in different cycles of huff and puff were established, and the optimal parameters for injecting CO₂ + surfactant were determined for huff and puff. Field application reveals a natural flow of a sing well for 240 days and an incremental oil production of 630 t. It is concluded that the CO₂ + surfactant combination huff and puff technology can effectively supplement formation energy and improve fluid mobility, which can be used as a reference for the development of similar reservoirs.