阿根廷San Jorge盆地凝灰质砂岩压裂测试特征分析

Fracturing test characteristics analysis of tuffaceous sandstone in San Jorge Basin, Argentina

针对San Jorge盆地SinopecArg工区凝灰质砂岩储层压裂完井有效期普遍较短以及低效改造的实际情况,从加砂规模、裂缝扩展情况等方面对盆地南翼15个区块中抽取的8个区块93口井共计216井次的测试压裂资料进行统计分析,发现工区内大致存在5种水力裂缝扩展或滤失特征,其中水力裂缝垂向上的过度扩展及先存微裂隙活化是压裂作业过程中的两大重要特征。从压裂测试响应机制上,认为凝灰质的存在导致垂直裂缝高度增加及先存微裂隙重新活化是加剧作业过程中脱砂风险的主要原因,最终影响工艺成功率及作业有效率。该工区的压裂测试特征分析为后续储层优化改造方案设计和施工参数控制提供了方向。

The effective period of the fracturing and completion of the tuffaceous sandstone reservoir in the SanopercArg work area of the San Jorge Basin was generally short and the stimulation efficiency was low.In order to solve these problems,the statistical analysis of 216 times of test fracturing data of 93 wells in 8 extracted blocks from 15 blocks in the south wing of the basin was carried out from the aspect of sand addition and fracture propagation.It was found that there were five types of hydraulic fracture propagation or fluid loss characteristics in the work area,of which the excessively extended hydraulic fractures and the activation of pre-existing micro-fissures are two important features in the fracturing process.Based on the response mechanism of the fracturing test,it was considered that there are two main reasons for increasing the risk of screenout fracturing during the operation;one is that the presence of tuff will lead to an increase in the height of the vertical fracture;the other is the reactivation of the pre-existing micro-fractures.These two factors ultimately affect the process success rate and operational effectiveness.The analysis of the fracturing test characteristics of the work area provides the direction for the fracturing design optimization and quality control.