微小井眼水泥浆体系室内性能评价

Laboratory performance evaluation on micro-hole slurry system

针对微小井眼固井环形间隙小,形成的水泥环薄等缺点,研制出了微小井眼水泥浆体系。并按照API标准对该水泥浆的密度、失水量及游离液、稠化时间、水泥石强度、耐盐耐温、耐腐蚀等性能进行了大量的实验评价。结果表明:微小井眼水泥浆体系不仅具有抗压抗折强度较高(抗压强度12.7 MPa,抗折强度6.0 MPa)、脆度系数低(仅2.1)的力学性能,且具有游离液为零、失水量小(<80 mL)、初始稠度低(<6 Bc)、直角稠化以及稠化时间可调等特点。同时为检验该体系的适应性,进行了耐温、耐盐、抗腐蚀性能评价。结果,该体系室内评价温度高达170℃,配浆盐水浓度高达12%。而且微小井眼水泥石具有较强耐酸、耐地层水腐蚀性能。微小井眼水泥浆体系完全可以应用于小尺寸,窄环空的井眼固井,同时由于其优良的适用性,有更广泛的应用前景。

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 ℃, 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.