超高压含硫气井井筒内天然气水合物解堵技术

为了安全、高效、经济地解除超高压气井井筒中的天然气水合物（以下简称水合物）堵塞，利用自主研发的固体自生热解堵剂在井筒内发生化学反应所释放出的热量来溶解水合物并防止其再次生成，通过调节解堵剂加量，来实现生热时间和生热量可调，进而将形成的化学自生热解堵技术在四川盆地超高压含硫气井的解堵作业中进行了应用。研究结果表明：①采用自主研发的固体化学自生热解堵剂，通过调整加量，可以实现生热峰值温度（34.2～88.5 ℃）、生热时间（24.2～884.0 min）可调，并且反应产物中包含有水合物抑制剂，能够抑制水合物再次生成；②随着解堵剂浓度增大，热传递速率加快，使解堵剂周围水合物的分解速率增加；③随着井筒内径增大，解堵时间延长，并且从64 mm增至76 mm对应的解堵时间增长率小于从76 mm增至102 mm对应的解堵时间增长率；④热量扩散模拟计算结果与现场实际用量的吻合率超过85%，证明所建立的化学自生热解堵剂热量扩散模型可靠，可以用于现场解堵剂加量的计算；⑤使用抗硫耐压140 MPa的固体药剂投加装置投加固体自生热解堵剂，在四川盆地超高压含硫气井已应用3井次，成功解除了水合物堵塞，使气井顺利恢复生产。结论认为，所形成的解堵技术针对超高压含硫气井井筒中形成的水合物堵塞的解除效果好、现场操作安全简单、费用低，具有较好的应用前景。

A blockage removal technology for natural gas hydrates in the wellbore of an ultra-high pressure sour?gas?well

In order to safely, efficiently and economically remove the blockages of natural gas hydrate (NGH) in the wellbores of ultra-high pressure gas wells, this paper utilized the heat released from an independently developed autogenetic heat based solid blockage remover through chemical reaction in the wellbore to dissolve NGH and prevent it from forming again. In addition, adjustable heat generation time and heat generation amount was realized by regulating the dosage of the blockage remover. Finally, the chemically autogenetic heat based blockage removal technology was applied to remove the blockages in ultra-high pressure sour gas wells in the Sichuan Basin. And the following research results were obtained. First, when the independently developed chemically autogenetic heat based solid blockage remover is adopted, the peak temperature (34.2-88.5 ℃) and time (24.2-884.0 min) of heat generation can be adjusted by its dosage What's more, there is NGH inhibitor in the reaction product, which can inhibit the regeneration of NGH. Second, as the concentration of the blockage remover increases, the heat transfer speed increases, leading to an increase of NGH dissociation rate around the blockage remover. Third, blockage removal time increases with the increase of wellbore ID. In addition, the increasing rate of the blockage removal time as the wellbore ID increases from 64 mm to 76 mm is lower than that from 76 mm to 102 mm. Fourth, the coincidence rate between the simulation calculation result of heat diffusion and the on-site actual consumption is more than 85%, which indicates that the proposed model for the heat diffusion of chemically autogenetic heat based blockage remover is reliable and can be used to calculate the dosage of blockage remover. Fifth, solid reagent adding device with resistance to sulfur and pressure of 140 MPa is used to add autogenetic heat based solid blockage remover. This blockage remover has been applied in the ultra-high pressure sour gas wells in the Sichuan Basin three well times. Thanks to its application, NGH blockages in these wells are removed successfully and their production is resumed smoothly. In conclusion, this blockage removal technology has such advantages as effective blockage removal, safe and simple on-site operation and low cost, and a promising application prospect.