不同油水比油基钻井液滤失性能的影响因素

Influence Factor of Filtration Property of Oil-based Drilling Fluid with Different Oil-water Ratio

为了揭示油基钻井液侵入地层后对钻井液滤失性的影响,通过调整油水比来模拟地层水侵入钻井液的体系,研究了有机土、降滤失剂(磺化沥青、氧化沥青、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)聚合物降滤失剂、有机胺改性腐殖酸及其复配)和温度对钻井液体系滤失性的影响,用显微镜观察了加入有机土前后不同油水比钻井液的微观形貌。结果表明,随着油水比的降低,钻井液高温高压滤失量呈降低趋势;有机土和降滤失剂均会降低钻井液的高温高压滤失量,降滤失剂复配后的降滤失效果好于单一降滤失剂,其中聚合物类和沥青类复配降滤失剂的降滤失效果最好;随着温度的升高,钻井液的高温高压滤失量逐渐增大;比较加入有机土前后不同油水比钻井液的微观形貌可见,随着油水比的降低,有机土在油基钻井液体系中作为悬浮剂和增黏剂的降滤失效果愈加明显。通过合理选择降滤失剂及有机土种类和加量可以有效调节油基钻井液的高温高压滤失量。

In order to reveal the influence of oil-based drilling fluid on the filtration property of drilling fluid after invading the formation,the effect of organic soil,fluid loss reducer(sulfonated asphalt,oxidized asphalt,2-acrylamide-2-methylpropanesulfonic acid(AMPS),organic amine modified humic acid and their compound)and temperature on the filtration property of drilling fluid was studied by adjusting the oil-water ratio to simulate the drilling fluid intruding formation water. The micro-morphologies of drilling fluids with different oil-water ratio before and after addition of organic soil were observed. The results showed that with decreasing oil-water ratio,the high temperature and high pressure fluid loss of drilling fluid tended to decrease. The organic soil and fluid loss reducer would reduce the high temperature and high pressure fluid loss of drilling fluid. The filtration reduction effect of compound fluid loss reducer was better than that of single fluid loss reducer. Among them,the fluid loss reducer composed by polymer and asphalt had the best fluid loss reduction effect. With increasing temperature,the high temperature and high pressure fluid loss of drilling fluid gradually increased. The micro-morphologies of different oil-water ratio drilling fluids before and after adding organic soil were compared. With decreasing oil-water ratio,the fluid loss reduction effect of organic soil as a suspending agent and tackifier in oil-based drilling fluid system was more obvious. The high temperature and high pressure fluid loss of oil-based drilling fluid could be effectively adjusted by reasonable selection of the types and additions of fluid loss reducer and organic soil.