Laboratory performance evaluation on micro-hole slurry system

To overcome the narrow annular and the thin cement mantle of micro-hole cementing, the micro-hole slurry system is developed. A lot of experiments are conducted to evaluate the density, the water loss and free fluid, the thickening time, the cement strength, the salt and temperature resistance, and the corrosion resistance of slurry system, according to the API criteria. Results show that the system presents high compressive (12.7 MPa) and flexural strength (6.0 MPa), and low brittleness coefficient (only 2.1). Besides, it has wonderful performance of no free fluid, low water loss ( 80 mL), low initial thickness ( 6 Bc), right angle thickening, and adjustable thickening time. At the same time, to examine the adaptability of the system, evaluation on its temperature resistance, salt resistance, and corrosion resistance is made. The result is satisfactory, the laboratory evaluation temperature reaches 170 °C, and the brine concentration is as high as 12%. Moreover, the cement has strong corrosion resistance to the acid and formation water. The micro-hole slurry system can be applied in small size or narrow annular wells cementing. It has broad prospect for application for its excellent adaptability.