高含硫气田钻井工程技术难点及应对措施——以土库曼斯坦阿姆河气田为例

Drilling engineering difficulties in high-sulfur gas fields in Turkmenistan and countermeasures

阿姆河右岸气田是土库曼斯坦主要产气区之一。为保障2006年中国政府同土库曼斯坦政府签署的300×108 m3天然气供应合同的顺利实施,首先对该合同区块过去勘探开发历程以及地质、工程情况作了深入分析,总结了该区块存在的工程难点、风险,并重点研究了钻井作业速度低和钻井报废的原因;然后,提出了满足高产气井的合理井身结构设计方案和井控装置配套方案,以及各层套管需要解决的地质工程难点,最后,制订了第三、四次开钻钻进控制盐水浸、膏盐溶解、膏盐缩径、井涌井喷等工程风险的应对技术措施。从2008年5月第1口井开钻到2012年5月,共钻井48口,无1口井报废,成功率达100%,平均建井周期156.75d,平均机械钻速3.17m/h,创造了该区钻井记录,形成了适合阿姆河右岸高温、高压、高含硫气田的一整套钻井技术。

The Amu Darya River Right Bank Gas Field is one of the major gas zones in Turkmenistan. In order to ensure a smooth implementation of the Natural Gas Supply Contract （300 ×10^8 m3） signed between the Chinese government and the Turkmen government, we first made a deep investigation into the past prospecting and drilling as well as geological and engineering conditions in this contracted zone; then summarized the existing difficulties and risks for the operations~ and focused on exploring the reasons for low drilling speed and well abandonment in this field. On this basis, we then proposed the rational wellhore configuration design and related well control mechanisms for a high yield, clarified existing geological engineering difficulties encountered respectively by each layer of casing, and finally worked out solutions to smooth out the engineering risks such as salt water encroachment, gypsum salt dissolution, hole shrinkage by gypsum salt, kicks, blowouts, and so on existing in the third and the fourth spud-in drilling opera- tions. By applying the above countermeasures, we have set a new record in this field by successfully drilling a total of 48 wells from May, 2008 to May, 2012 with a success ratio of 100% , with no well abandoned, and with an average well construction period of 156.75 days and the average penetration rate of 3. 17 m/h; the most important of all, a full set of drilling techniques have been formed suitable for the high temperature and high pressure gas wells with a high sulfur content in the Amu Darya River Right Bank Gas Field.