厄瓜多尔Tambococha油田水平井钻井液技术

厄瓜多尔Tambococha油田由于钻遇松散且微裂缝发育的地层,钻进中井壁易垮塌;其目的层高孔高渗,易发生储层损害问题.为此,以聚合醇XCS-III和乳化石蜡G325为主剂,通过优选其他环保型处理剂,研制了强封堵储层保护水基钻井液.该钻井液利用乳化液滴、浊点效应、微米颗粒及刚性粒子等的协同封堵作用来降低油水界面张力,阻...

Drilling Fluid Technology for Horizontal Wells in Ecuador Tambococha Oilfield

The borehole wall sloughing easily happens during drilling due to the unconsolidated formation with micro-fracture development in Tambococha Oilfield, Ecuador. The target stratum is characterized by high porosity and high permeability, causing reservoir damage. For this reason, with polyalcohol XCS-III and emulsified paraffin G325 as the main agents, accompanied by optimized eco-friendly agents, water-base drilling fluid that would provide strong reservoir protection during plugging were studied. The drilling fluid utilized the synergistic plugging effect of emulsified droplets, cloud point effect, micron particles and rigid particles to reduce the oil-water interfacial tension. It prevented the drilling fluid from entering the formation, finally achieving anti-collapse plugging and reservoir protection. Laboratory experiments showed that the drilling fluid had strong inhibitory properties, reducing the linear expansion of cuttings by 64.8% compared with that in clean water. The plugging performance was good, and its particle size distribution was consistent with the ideal filling curve. The damage to the reservoir was minor with an average damage rate of 10.25% to the cores of Layer U in the Napo Formation. The drilling fluid was eco-friendly, and the content of heavy metals met the standards for sewage discharge. The drilling fluid system was successfully applied to 15 horizontal wells in Tambochocha Oilfield, achieving good wellbore stability and smooth tripping. The average daily crude oil output of a single well exceeded 300 t, which was nearly 90% higher than that of offset wells. Such envi-ronmental indicators as waste drilling fluid and drilling cuttings met the requirements of EPA1311 discharge standards. The research results showed that the water-base drilling fluid could meet the rate of penetration (ROP) improvement and reservoir protection requirements of horizontal wells in Tambococha Oilfield, Ecuador.