北部湾盆地简易井口新型隔水导管应用研究

在北部湾盆地,油气开采设备需满足百年一遇的台风海况要求。常规探井普遍采用一开双眼,并将ø508 mm套管作为表层隔水导管,下入ø508 mm和ø339.7 mm复合套管,较难保障固井质量。为提高固井质量,并进一步节约工程投资,采用有限元方法建立隔水导管稳定性分析模型,探究了水深、隔水管外径、壁厚等因素对简易井口隔水管井口允许载荷的影响规律,确定了主控因素强弱顺序为:外径> 壁厚>钢级>水深>井口高度,且外径对井口允许载荷的影响远大于其它因素。在此基础上,对北部湾盆地乌石海域探井隔水导管进行优化研究, 在非台风季节时,实现了新型小尺寸套管作为隔水导管在北部湾W井的首次应用。该隔水导管优化技术的成功应用,为后续探井的井深结构优化、进一步提高作业时效、降本增效提供借鉴。

Application Study of New Type of Water-blocking Conduit for Simple Wellhead in Beibu Gulf Basin

Oil and gas exploration equipment needs to meet the typhoon sea conditions that are once in a hundred years in the Beibu Gulf Basin. The Conventional exploratory wells generally apply one open eye, and the 508 mm casing as the surface water conduit with the inserted 508 mm and 339.7 mm composite casings, which makes it difficult to guarantee the cementing quality. In order to improve cementing quality and save the engineering investment, the finite element method was applied to establish the stability analysis model of the water-blocking conduit. The influence of water depth, outer diameter of the riser and wall thickness on the allowable load of the wellhead of the simple wellhead were investigated. The order of the main control factors is confirmed as: outer diameter > wall thickness > steel grade > water depth > wellhead height, and the influence of the outer diameter on the allowable load of the wellhead is much greater than other factors. On this basis, the optimization study of the wells in the Wushi sea area of the Beibuwan Basin was carried out. In the non-typhoon season, the new small-sized casing was used as the water-blocking conduit for the first time in the Beiwan Gulf Basin. The successful application of the water conduit optimization technology provides a reference for the optimization of the well depth structure of the subsequent exploration wells.