河坝1井高压含硫气层井控技术

Well Control Technology for High Pressure Gas Zone Containing Sulfide in Heba 1 Well

河坝1井是川东北部通南巴构造带上的一口重点探井,全井预计产层9个,地层压力相差较大,而且海相地层裂缝、溶洞发育,很容易出现“喷漏同存”的复杂情况,不利于井控。加上碳酸盐岩地层压力预测不准,天然气中含有硫化氢以及井场自然条件的限制,该井井控难度极大。为此,该井不但应用了高压抗硫井控装备、配备了气体监测仪器、做好了各种应急预案,而且在钻井过程中也采取了地层承压堵漏、简化下部钻具组合、近平衡压力打开产层等预防井喷、井涌的工程技术措施。该井共发生井涌2次,但均压井成功,顺利钻至设计井深。

Heba 1 Well is an important exploration well situated in the northeastern Sichuan, which penetrates the Tongnanba structure. Nine pay zones are forecasted through the well. Being high formation pore pressure differences, developed fractures and caves, the complicated situation that blowout while loss is likely to happen, which is not good to well control. In addition, restrictions from not accurate forecast for pore pressure in the carbonate formations, containing hydrogen sulfide in gas, and rig site conditions, etc. make well control much more difficult. Regarding such scenario, high pressure and anti sulfide well control equipment, gas detection apparatus are fitted, various emergency measures are taken, in addition, a lot of engineering measures are taken while drilling to prevent blowout and kick, including blocking leakages with high pressure, simplifying BHA, penetrating pay zones under approximate balance pressure. Two kicks happened all together, which were all be killed successfully, and the well was finally drilled to the planned depth.