Reservoir Evaluation and Development ›› 2018, Vol. 8 ›› Issue (3): 40-45.

• Petroleum Engineering • Previous Articles     Next Articles

Study on scaling mechanism and its effect on water flooding in Shahejie formation of QK 18-1 Oilfield

Shen Jianjun1,Tang Hongming1,Wang Yijun1,Gong Xiaoping2,Yu Hao1   

  1. 1. School of Earth Science and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China
    2. Northeast Sichuan Gas Production Company, Southwest Petroleum Bureau, SINOPEC, Chengdu, Sichuan 637402, China
  • Received:2017-06-30 Online:2018-06-26 Published:2018-12-07


QK 18-1 Oilfield is located in the western Bohai sea. After 10 years of water flooding, the water injection now is difficult. In 2013, the sealed coring was conducted on the well P13. The core represented large amounts of the information after the long term of the water flooding, including the pore structure changes, the inorganic scale plugging, etc. By comparing the interstitial materials in the reservoir of the exploratory wells in the early stage and the exploitation wells in the late stage, we used many methods, such as the low field NMR, the electron microprobe, the environmental electron microscope, the cathodoluminescence and the rock cast sections, to study the inorganic scale in the reservoir and determine the formation mechanism of the scaling crystal in the reservoir. The results showed that the CaCO3 cements in the early stage of the reservoir presented as the crystal or the porphyritic distribution were the products of the diagenetic stage. The well P13 contained a large number of rhombohedral CaCO3 scales with the grain diameter of 5 ~ 30 μm and great euhedral degree of the scale. And the scale mainly distributed around the surface and the throat of the skeleton particles with high content of Mg and Fe formed during the water flooding. The average reservoir water damage rate was 44.5 % and the average velocity sensitive damage rate was 139.5 %. The clay minerals generated by swelling of part of the scale with water, the mobile formation particles and the suspension matter in water wrapped together to form a composite inclusion, accumulating in the pore space to damage the reservoir

Key words: water injection, calcium carbonate scale, electron probe, reservoir damage, compatibility

CLC Number: 

  • TE357