南海深水水基钻完井液防水合物技术

Deepwater Water-based Mud Hydrate Inhibition Technology in South China Sea

摘要:

深水区油气钻完井作业相比浅水区和陆地遇到了很多难题,由于海底压力增大和低温的环境,天然气水合物已成为影响深水钻井安全的主要危害之一。目前，国际上深水钻完井作业中通常采用油基钻井液来防水合物，但是油基钻井液环保风险高，为此在陵水区块超深水钻完井作业中尝试采用水基钻完井液进行作业。鉴于国内无类似经验可循，结合陵水区块超深水井的实际情况，首先模拟分析了2口井的水合物风险，明确该区块水合物形成的条件；其次，针对水合物形成的风险，筛选合适的抑制剂及钻完井液配方；在此基础上，研究出相配套的工艺措施。陵水区块深水钻井作业的成功实践表明，由此形成的一套深水水基钻完井液防水合物技术在深水钻完井作业中能够较好地防治天然气水合物，保障作业安全，对后续类似深水井的作业具有借鉴意义。

Abstract:

Compared to shallow water and onshore drilling, a number of technical difficulties are encountered in deepwater drilling and completion. Due to subsea high pressure and low temperature, hydrate has become a main threat to the safety of deepwater drilling and completion operation. Currently, OBM is the priority to prevent hydrate generation in deepwater drilling and completion. However, OBM is not environmental-friendly compared to WBM, so the latter was selected to use in ultra-deep water drilling. In view of the absence of similar experience, according to the actual situation of ultra-deep well in Lingshui block, the hydrate risk of 2 wells are simulated in order to identify hydrate generation condition; on the other hand, aiming at the risk of hydrate generation, proper hydrate inhibitor and drilling & completion fluid are selected. On the above basis, the matching technical scheme has been worked out. By the successful practice of deepwater drilling in Lingshui block, it is proved that WBM hydrate inhibition technology can well prevent hydrate generation during deepwater drilling operation and ensure operation safety, which has great reference and popularization value for the similar deep water well operation.