哈萨克斯坦AKS油田裸眼水平井分段压裂措施效果评价

Effect evaluation of separate layer fracturing stimulation for open-hole horizontal wells in AKS Oilfield of Kazakhstan

哈萨克斯坦AKS油田M-Ⅱ-4储层为砂砾岩,是低孔、低渗储层,属于难采储量。为了进一步提高油田开发效果,该油田在水平井ASY77井开展了裸眼水平井分段压裂现场试验。通过对试验井的基础数据和储层地质特征的了解,综合对比分析了压裂管柱设计、地应力解释、小型测试压裂分析,以及主压裂优化设计及压裂后的效果情况。研究表明:裸眼水平井分段压裂技术增产效果显著,压裂后平均自喷日产液量为65m^3,平均日产油量为40m^3,是砂砾岩直井压裂后平均日产液量的2. 3倍,但其压裂施工设计的横向裂缝间距过大、压裂规模过小,导致压裂后导流能力较低,具有进一步的优化潜力。通过该研究提出的针对性建议和攻关方向,可为AKS油田及海外类似油田今后的裸眼水平井压裂施工优化设计提供理论和技术支撑,确保油田开发效果。

M-II-4 reservoir in AKS Oilfield of Kazakhstan is low-porosity and low-permeability reservoir with glutenite,which is hard to be exploited.The open-hole horizontal well separate layer fracturing test was conducted in the horizontal well ASY77 in order to further improve the oilfield development effect.Based on the understanding of basic data of the test well and the geological characteristics of reservoir,comprehensive comparison and analysis with regard to design of frac string,explanation of crustal stress,analysis of small scale test fracturing as well as optimization design of the main fracturing and effect after fracturing were implemented.The study proves that the stimulation effect of open-hole horizontal well separate layer fracturing is remarkable.The average daily flowing liquid production after fracturing is 65m3;and the average daily oil production is 40m3,which is 2.3 times of the average daily liquid production of glutenite vertical well after fracturing. However, the horizontal fracture distance infracturing operation design was too large and its fracturing scale was too small, resulting in low flowing conductivityafter fracturing, so it has the potential of further optimization. Directive suggestions and research can providetheoretic and technical support for optimization design of open-hole horizontal well fracturing operation in AKSOilfield and similar overseas oilfields in the future so as to ensure the effect of oilfield development.