流沙层硬胶泡沫钻井技术

也门1区块上部地层250~750 m井段存在大段的流沙层,钻进过程中存在井壁失稳、漏失严重、机械钻速低等问题,单纯依靠常规钻井加堵漏、清水盲钻、空气钻井或稳定泡沫钻井等方式得不到有效解决。因此,提出采用硬胶泡沫钻井方法解决该问题。通过硬胶泡沫钻井流体发泡剂室内优选试验,考虑泡沫质量、发泡剂抗污染性能、硬胶泡沫半衰期及经济效益,选择FMA-100为硬胶泡沫钻井流体的发泡剂,确定其最佳加量为0.3%~0.6%,并初步优选出钻井流体配方。根据硬胶泡沫钻井施工参数设计要求,以低返速降低井壁冲刷防塌、合适当量循环密度防塌防漏为目标,通过理论计算及分析,优选了施工参数、钻井配套设备,形成了适用于也门1区块流沙层的硬胶泡沫钻井方案。该方案在该区块Abyed-2井进行了应用,不但成功解决了大尺寸疏松流沙层井漏与井塌并存的钻井难题,还提高了流沙层的机械钻速,相比同条件邻井平均机械钻速提高3.2倍。该井的应用成功,也为流沙层安全快速钻进积累了经验。 

Stiff Foam Drilling Technology in Drift Sand Formation

Heavy drift sand formation exists in the upper formation 250-750 m of block 1 in Yemen,so concurrent problems such as wellbore instability,serious loss circulation and low ROP present during the drilling of this section.Those problems can not be solved through conventional drilling with lost circulation materials,blind drilling with fresh water as well as air drilling and stable foam drilling.Therefore,this paper proposes the ebonite foam drilling method.Through foaming agent optimization test of ebonite foam drilling fluid in the laboratory,we selected FMA-100 as the foaming agent based on foam quality,anti-contamination performance of foaming agent,ebonite foam half-life,and economic benefits analysis.In the test it demonstrated the optimal added amount to be 0.3%-0.6%,then preliminarily optimized the drilling fluid formula.To prevent wellbore collapse and lost circulation with low return velocity and appropriate equivalent circulation density,this paper optimizes operation parameters,drilling equipment,and forms program of drilling the drift sand formation applicable for Yemen 1 Block through theoretical calculation and analysis.The program was then applied in Well Abyed-2 of the same block and it not only successfully resolved the lost circulation and collapse coexisting problem in the large size loose drift sand formation,but also improved the ROP of drift sand formation to 3.2 times the average ROP of adjacent Wells.The successful use of ebonite foam drilling program in this well lays solid foundation for forming drift sand formation ebonite foam drilling technology.