Safe and Efficient Drilling Technology and Practice of High Risk Gas Reservoirs on the Right Bank of the Amu Darya Rive

The right bank of Amu Darya gas field is an important oil and gas cooperation block of China ‘s overseas oil and gas business in the ‘ silk road economic belt ‘, due to the local shallow secondary high pressure gas reservoir and the target layer overlying thick salt gypsum layer, seriously affected the work area of safe and efficient drilling. Before the intervention of CNPC, 192 wells were drilled in this area, of which the engineering scrap rate was 23% and the geological scrap rate was 41%. In order to effectively solve the difficulties in the drilling operation on the right bank and improve the success rate of drilling, the drilling technology of shallow secondary high-pressure gas reservoirs and giant thick salt-gypsum gas reservoirs at home and abroad was investigated. Combined with the geological characteristics of the Amu Darya gas field, the drilling engineering scheme was formulated, the advanced and complete drilling equipment was matched, and the field test and scheme optimization were carried out step by step. In view of the drilling risk caused by shallow secondary high-pressure gas reservoirs, the countermeasures of detecting the underground situation of slim hole wells, and then casing sealing after passing through dangerous formations according to the design expansion are adopted. In view of the difficulties in trajectory control of highly deviated wells in extremely thick salt-gypsum layers, the wellbore structure and wellbore trajectory design were optimized, and the directional drilling fluid for salt-gypsum layers was optimized. A series of trajectory control measures for salt-gypsum layers were proposed in combination with dynamic drilling tools and MWD technology. Finally, combined with the formation.