深层碳酸盐岩储层泥砂产出与固体控制优化

Sand production and solid control optimization in deep carbonate reservoirs

碳酸盐岩储层原油储量巨大但开采过程中井壁坍塌和出泥砂严重,工程表象为岩块、岩屑及泥砂沉积在井筒内,砂埋产层影响油井产能。使用多功能驱替挡砂性能评价装置,精度为250、350、450及550μm的金属滤网切片及3口典型失稳井冲捞砂样,开展碳酸盐岩储层井壁坍塌与泥砂产出固体控制模拟试验,通过采集压差、流量等动态数据,定量评价挡砂介质的挡砂性及流通性,分析固体控制的可行性并进行精度优化。结果表明:利用精度250~550μm金属滤网阻挡中值粒径为289.5μm泥砂及岩屑/岩块和中值粒径为40.3μm的纯泥砂,挡砂介质的过砂率均小于12%,堵塞平衡渗透率均大于1.3μm^(2),针对碳酸盐岩失稳井进行固体控制可行;针对碳酸盐岩储层中值粒径为289.5μm的泥砂与岩屑/岩块复合产出,推荐控砂筛管的挡砂精度为0.5~0.6 mm,或在保证挡砂性能的前提下适当放宽筛管精度;针对碳酸盐岩储层中值粒径为40.3μm的纯泥砂产出,推荐挡砂精度为0.3~0.4 mm;针对碳酸盐岩储层的高产井,推荐进行适度携砂生产。

Borehole wall collapse and sand production are of great concerns during oil and gas production process from carbonate reservoirs,in which rock blocks,cuttings and sands can be accumulated in wellbore,causing blockage and reducing the productivity of the oil well.In this study,a multi-functional sand displacement performance evaluation device was used to conduct experiments of borehole wall collapse and sand production in carbonate reservoirs.Metal mesh slices with precision of 250,350,450 and 550 μm and sand samples from three typical unstable wells were used in the experiments.Sand retention and liquidity of sand retaining medium were quantitatively evaluated using the dynamic data of pressure and flow rate,and the feasibility of solid control was analyzed and its precision was optimized.The experimental results show that the metal filter with a precision of 250-550 μm can be used to effectively block sands with a medium size of 289.5 μm and cuttings/blocks or pure sands with a medium size of 40.3 μm.The sand passing rate of the sand retaining medium was less than 12% and the plugging equilibrium permeability was more than 1.3 μm^(2),indicating that the solid control for carbonate unstable wells is feasible.The results of screen precision optimization show that for the composite production of sands with a medium size of 289.5 μm and cuttings/blocks in carbonate reservoirs,it is recommended that the screen precision should be of 0.5-0.6 mm,or the screen precision should be appropriately expanded on the premise of ensuring sand retention performance.For the production of pure sands with a medium size of 40.3 μm,the screen precision can be improved to 0.3-0.4 mm.Production with a moderate sand carrying or sand-out is recommended for high yield wells in carbonate reservoirs.