南海北部超深水气田探井测试作业实践与认识

Engineering Practice and Understanding for Utra-deepwater DST in the South China Sea

随着油气勘探逐步走向深海,如何安全高效的实现油气井测试已成为深水油气勘探的关键。南海北部陵水LSE-1井为我国第一口超深水气井,测试作业面临着多个难题:低温高产流体在测试管柱内水合物生成风险极大,超深水条件下多种动载荷联合作用更为复杂,安全风险高;气层埋深仅在泥面以下1 200 m,孔隙度高,出砂风险极高;常规取样方式不能满足安全要求和样品品质要求。基于面临的困难,结合已有深水测试作业技术与经验,通过调整水合物防治措施、制订严格的应急解脱决策系统及节点管控预案、改进模块化地面测试流程、采用新型一开一关测试程序以及压控式井下PVT取样技术等关键工艺措施,安全高效地取得了测试作业的成功,准确评价了我国首个超深水气田。新工艺的成功应用将为我国深水油气勘探提供有力的技术支撑。

With the Oil&Gas exploration gradually moves into the deep sea, how to safely and efficiently implement the oil and gas well testing has become the focus of attention. Well LSI 8-1-1, located in the northern South China Sea, was the first ultra-deepwater gas well, and its testing work faces many problems: high risk of hydrate formation for low temperature and high rate fluids in the test tube ; various dynamic load combination under the condition of ultra-deepwater is more complex ; gas reservoir buries only 1 200 m below the mud surface with high porosityand high risk of sanding; conventional sampling methods cannot meet the safety and quality requirements. Tosolve these problems, combined with current deep-water testing technology and experience, testing operation was completed safely and efficiently by taking several key technological m easures, such as adjusting the hydrate prevention measures, formulating strict emergency relief decision-making system and node control plan, improving the modular ground test process, using the novel once on-off test procedure and pressure-controlled downhole PVT sampling technique, which contributes to the accurate evaluation of the first ultra-deepwater gas field in China. The successful application of new technologies will provide powerful technical support for the deepwater oil and gas exploration in China.