渤南油田高温注水井欠注层伤害机理研究

The study on damage mechanism in high temperature water-injection wells of Bonan Oilfield

渤南油田五区沙三段九砂组油藏属中等水敏性和速敏性的地层;油藏为轻质油-稀油油藏,原油具有低密度、低粘度和高凝固点等特点,组分含硫量低;地层水总矿化度较高,一般为1100～19900 mg/L,水型为NaHCO3型。研究了渤南油田注水井伤害机理,从地层特性、注入水水质、悬浮物堵塞、游离油和乳化油滴、结垢、细菌及以往增产措施等方面评价了可能对储层造成的损害及损害程度。渤南油田地层的水敏性、速敏性和低渗透特性是注水井损害的内在因素,注入水中悬浮固相颗粒、含油量和细菌严重超标,水质不合格是注水井损害的外在因素;注入水中悬浮固相颗粒和油的含量高,易形成盐酸不溶垢和有机垢;细菌和油质的共同作用增加管路的腐蚀,形成铁垢,逐渐降低地层的渗透率,严重时堵塞地层。

Damage mechanism in high-temperature water-injection wells of Bonan Oilfield has been studied based on the evaluation of formation characteristics, injection water quality, suspended solid, free oil, emulsified oil droplet, fouling, bacteria, well stimulation, etc. . The sand formation of Bonan oilfield is intermediate water sensitivity and velocity sensitivity, and the reservoir type is lightweight oil/thin oil reservoir. The density, viscosity and sulfur of the crude oil are low but its freezing point is higher. The total mineralization of formation water is as high as 1100~ 19900 mg/L, and the water type is NaHCO3. The study has shown that water sensitivity, velocity sensitivity and low permeability of formation in Bonan are the external factors of the damage. And suspended solid granula, oil content, serious bacteria index and fallen short water quality of flood water are the intrinsic factors, i. e. , high suspended solid granula and oil content of flood water form frequently insoluble and organic dirt-y; the combined effects of bacteria and oil increases the corrosion of pipe and form iron dirty, these reasons cause the permeability of formation reducing and formation plugging.