CO2 干法压裂液体系的研究与试验

Research and test on CO2 dry fracturing fluid system

汪小宇 宋振云 王所良

WANG Xiaoyu SONG Zhenyun WANG Suoliang

川庆钻探工程有限公司钻采工程技术研究院，陕西西安　710018 中国石油天然气集团公司油气藏改造重点实验室CO2 压裂增产研究室，陕西西安　710018

Drilling and Production Engineering Technology Research Institute of Chuanqing Drilling Engineering Co. Ltd, Xi’an 710018, China CO2 Fracturing Stimulation Laboratory, CNPC Key Laboratory of Oil and Gas Reservoir Reform, Xi’an 710018, China

为提高低压、低渗透、强水锁/ 水敏伤害致密砂岩储层压后产量，开展了CO2 干法压裂液体系的研究。采用分子模拟技术，研究液态CO2 与提黏剂分子间微观构型，评价不同CO2 提黏剂对液态CO2 的提黏效果，优选提黏剂，并建立CO2 干法压裂液体系配方。通过研究发现，在62~63 ℃、15~20 MPa 条件下，CO2 干法压裂液体系黏度提高至5~10 mPa·s，较超临界CO2 的黏度提高240~490 倍；对气井岩心渗透率平均损害率为2.75%，对油井岩心渗透率平均损害率为0.98%。该压裂液体系在苏里格气田成功进行了国内第1 口CO2 干法加砂压裂现场试验，增产效果明显。

In order to increase the production of low pressure, low permeability, strong water locking or water sensitive damaged tight sandstone reservoir after fracturing, research was conducted on CO2 dry fracturing fluid system. The molecular simulation technique was used to study the microscopic configuration of molecules between liquid CO2 and viscosifier, to evaluate the viscosifying effect of various CO2 viscosifer on liquid CO2 , to optimize the viscosifiers, and to build the formula for CO2 fracturing fluid. Based on the research, it was found that, under the conditions of 62–63 ℃ and 15–20 MPa, the viscosity of CO2 dry fracturing fluid system was increased to 5–10 mPa·s, which is 240–490 times that of supercritical CO2. The average rate of damage to core permeability of gas wells was 2.75%, and the average rate of damage to core permeability of oil wells was 0.98%. This fracturing fluid system was successfully tested on the first domestic well with CO2 dry sand fracturing in Sulige Gas Field, and the production was increased remarkably.

10.13639/j.odpt.2014.06.017