Development of water-based drilling fluid used in unconsolidated sandstone reservoir

ABSTRACT

According to the fact that there is some little research on drilling fluid used in unconsolidated sandstone reservoir while conventional drilling fluid can not meet the requirements, we developed a new kind of water-based drilling fluid system. In this paper, bentonite, filtrate reducer, inhibitor, and other additives were optimized according to the characteristics of unconsolidated sandstone formation and several properties like rheology, filter loss, inhibition, and so on. A new drilling fluid system was developed and it was finally determined to be 5% Na₂CO₃ + 4% bentonite +0.2%PAC+ 0.7%FLA1 + 2%IHT1 + 3%GSJ +0.8% WHA1. The density, apparent viscosity, plastic viscosity, and yield point of this system were 1.18 g/cm³, 38.2 mPa·s, 24 mPa·s, and 17.2 Pa, respectively. Its filter loss was 6.2 ml, thickness of filter cake was 0.5 mm, roll recovery of rock samples was 88%, and the expansion amount was 0.18 mm. In immersion experiment, there was no obvious cracks on core samples. The result showed that this drilling fluid system can effectively clean the unconsolidated sandstone borehole and its filter loss performance, rejection capability, and antipollution properties were pretty good.

KEYWORDS:

• Unconsolidated sandstone reservoir
• water-based drilling fluid system
• additive optimization
• property investigation
• drilling fluid formulation

Acknowledgments

Tis project was funded by 2017 China Petroleum Science and Technology Innovation Fund Project: Research on EOR technology of low permeability reservoir based on 3D reservoir physical model, thanks to this project. I would like to thank my tutor Yi Pan and ShuangChun Yang for their conscientious guidance and I would also like to thank my teammates for their help and suggestions during my experiment.

Additional information

Funding

This work was supported by the 2017 China Petroleum Science and Technology Innovation Fund Project: Research on EOR technology of low permeability reservoir based on 3D reservoir physical model [under Grant number 2017D-5007-0201].

Notes on contributors

Xu Zhao

Xu Zhao is pursue the degree on oil and gas development engineering of Liaoning Shihua university, and his research focus on enhance recovery rate.

Qiushi Dai

Qiushi Dai master, received his oil and gas well engineering degree from Liaoning Shihua university in 2015,now he focus on drilling fluid.

Yi Pan

Yi Pan professor, received his Phd on Geological Resources and Geological Engineering of China Petroleum University (Beijing) in 2011,and his research is about the working oilfield development engineering.

Shuangchun Yang

Shuangchun Yang received her Phd on Environmental and Chemical Engineering of China Petroleum University (Beijing) in 2011, and now she is a professor of Liaoning Shihua University.Her research is on the working fluid and environmental engineering of oilfield.

Wakam Fogaing Marcellin

Wakam Fogaing Marcellin is pursue the master degree on oil and gas well engineering of Liaoning Shihua university, and his work is about drilling fluid.

Wei Li

Wei Li is a master student of Liaoning Shihua university, and his major is  oil and gas development engineering, his work is on enhance recovery rate.

Haiyan Zhang

Haiyan Zhang professor, received her Phd in Chemical Engineering and Technology from China Petroleum University (Beijing) in 2010,and her research work is on the chemistry and technology of petroleum.