环空加砂压裂管柱流体压降分析及现场应用

连续油管(CT)水力喷射压裂技术是提高低渗透油藏开发效率的一种重要手段。选择压裂作业连续油管时需要考虑连续油管及套管的强度及尺寸,不仅要保证压裂施工作业过程中管柱结构安全可靠,而且还要保证压裂施工中高压力、大排量要求。环空喷射压裂作业就是为了满足现场施工大排量而采取的一种有效措施,然而,增大环空排量会增加环空流体摩阻压降,摩阻压降又会直接影响地面设备选择、以及井下压裂作业成功与否。因此,针对连续油管水力喷射压裂环空流的流动特点,通过理论分析及现场数据回归的方法开展连续油管环空喷砂压裂环空流体压降分析,主要研究内容包括:连续油管偏心、流体流变参数对压裂液环空流压降规律研究。分析结果表明:连续油管偏心降低了环空流体摩阻压降,且影响明显;流变指数及压裂管柱尺寸增加,油套环空流体摩阻压降增加;压裂液环空流压降为清水压降的36%,根据校正Gallego F理论模型可以准确预测压裂液环空流压降梯度变化规律。研究成果可为连续油管环空压裂施工及设计提供理论指导。

Pressure Loss Analysis and Field Application of Annular delivery Sand Fracturing

Coiled tubing hydraulic jet fracturing technology is an important method to enhance the recovery ratio of low permeability reservoir. It needs to consider intensity and size of coiled tubing and casing for the choice of coiled tubing fracturing operation, not only to guarantee the reliability of string structure in the process of fracturing operation, but also to ensure the requirements of high pressure and large discharge capacity. An effective measure of annular jet fracturing operation is taken to meet the requirements of field operation. However, with increasing of annular discharge, annular flow friction pressure loss is also increasing. At the same time, it also directly influences the choice of ground equipment and success or failure of fracturing operation. Therefore, based on the flow characteristics of coiled tubing annular flow of hydraulic jet fracturing, it is necessary to carry out analysis of annulus flow pressure loss in coiled tubing annular jet fracturing operation with the methods of theoretical analysis and field data regression. The main research contents include: annular pressure drop rule research under the conditions of coiled tubing eccentric and fluid rheological parameter. The results of the study show that it is obvious that the coiled tubing eccentric reduces annulus fluid friction pressure loss in annulus. Fracturing fluid annulus flow pressure drop of the water pressure drop of 36%, and Gallego F correction model can accurately predict fracturing fluid annulus flow pressure drop gradient change rule. In this paper, the research achievement provides theoretical guidance for coiled tubing fracturing operation and design.