南堡潜山油气层钻井完井液技术

冀东油田南堡潜山油气藏埋藏深(4000~5600 m),地温梯度大(4.22°/100 m),井底最高温度为223℃,地层压力系数低,为0.96,储层微裂缝发育,气油比大。为满足其储层保护和安全生产的需要,研究了抗220℃高温低密度低固相钻井液和抗170℃高温冻胶阀技术。抗高温低密度低固相钻井液选择2种四元共聚物分别作抗高温增黏剂和抗高温降滤失剂,并配合使用SMP和SPNH以及耐温封堵剂FT3000,抗高温水包油钻井液由研制的抗温能力强、抗盐能力好的HWZR和HWFR乳化剂,优选出的增黏剂HVF-H和抗高温降滤失剂HWFL-H与HVS-H等组成,2套体系在220℃老化48 h性能良好,可满足井眼清洁的需要,使用密度范围为0.98~1.08 g/cm3;抗高温冻胶阀实现了起下钻和套管回接过程分隔油气层和保护油气层的目的。目前已钻井22口,8口探井应用了抗高温低固相钻井液,13口开发井应用了水包油钻井液,2口井应用了抗高温冻胶段塞封堵技术,均取得良好的效果,确保了全过程油气层保护。

Drilling Fluid Technology for Drilling Nanpu Buried Hill Oil Reservoir

The Nanpu buried hill oil reservoir(Jidong Oilfield) is characteristic of deep burial at 4, 000-5, 600 m, high formation temperature(4.22℃/100 m, and 223℃ atbottom hole), low formation pressure(pressure coefficient 0.96), and developed fractures.The produced oil has high gas/oil ratios.A high temperature low density low solids content drilling fluid and a high temperature gel plug have been developed for use in reservoir drilling in Nanpu.The high temperature drilling fluid retains its good performance at 220℃, and the gel plug functions at 170℃.In formulating the high temperature low density low solids drilling fluid, two tetra-polymers were chosen as the high temperature viscosifiers and high temperature filter loss reducer, respectively.SMP, SPNH and a high temperature sealing agent, FT3000, were also used to improve the properties of the drilling fluid.A high temperature oil-in-water drilling fluid was formulated with two emulsifiers, HWZR and HWFR, (both are high temperature stable and salt resistant) a viscosifier HVF-H and two high temperature filter loss reducers, HWFL-H and HVS-H.The two drilling fluids have good performance after aging at 220℃ for48 h, and densities ranging between 0.98 g/cm3 and 1.08 g/cm3.Using the gel plug, oil and gas zones are isolated and protected during pipe tripping and casing tieback.The high temperature low density low solids drilling fluid has been used in 8 wells, the oil-in-water drilling fluid used in 13 wells, and the gel plug used in 2 wells, all proved successful in reservoir protection.