气田水平井防砂筛管类型优选与精度优化试验

机械防砂筛管是疏松砂岩气藏防砂完井管柱的关键组成部分,其总体结构和挡砂介质性能决定了挡砂效果和气井防砂后产能以及总体服务期限。南海X气田为疏松砂岩易出砂气藏,为选择合适的水平井二次防砂机械筛管类型并优化挡砂精度,使用自行研制开发的挡砂介质性能评价径向流驱替试验装置,模拟该气田地层砂和生产条件,对单层网布复合筛管、双层网布复合筛管、复合绕丝筛管、多层精密筛管、孔网复合筛管等5种类型的筛管样品进行了综合性能评价试验;根据动态试验数据,提出筛管的流通性能、挡砂性能及其评价指标的计算方法,系统地评价5种筛管的各单项性能和综合性能,并得到具体的量化评价指标。为优化挡砂精度,使用从0.08~0.18mm的5种不同精度的双层网布复合筛管分别阻挡粒度中值0.08mm的模拟地层,测试与评价各精度筛管的综合防砂性能。结果表明,对于南海X气田不产水粉细砂气藏水平井,双层网布绕丝筛管和精密筛管的流通性能、挡砂性能等综合指标较高,依次推荐为气田二次防砂最佳筛管类型;最终推荐该气田二次防砂挡砂精度为0.1~0.12mm。

Experimental study on selection of mechanical screens and sand retention precision design for horizontal wells in a gas field

Mechanical screen is a key component for downhole sand control in unconsolidated sandstone reservoirs, and its type and comprehensive characteristics have a great impact on sand retention capability, well productivity and service life. In order to select a proper screen type and optimize sand retention for X gas filed in South Sea with typical sandstone formation and severe sanding problem during production, various parameters, such as screen conductivity, sand retention capability and a corresponding evaluation index, can be used to characterize the screen ''s comprehensive sand control capability. A series of sand control experiments were conducted using an in-house experimental set up with sand samples from the field and under the production conditions. Six types of screens were tested, including a single-layer mesh compound screen, a two-layer mesh compound screen, a slotted linear screen, a wire-wrapped compound screen, a multi-layer mesh screen and a star-hole metal cotton screen. The performance index of each screen tested was calculated based on the experimental results. It indicates that, to control the fine sands from the gas reservoir with no water production, the two-layer mesh compound screen and the multi-layer mesh screen are the bests for use, which exhibited a good performance for sand retention, flow deliverability and anti-plugging. To optimize the sand retention precision, the two-layer mesh compound screens with six different sand retention accuracy from 0.1 to 0.15 mm were tested using simulated formation sands with median size of 0.08 mm. The experimental results show that the optimum sand retention accuracy is 0.1-0.115 mm for X gas field.