Research And Application Of Horizontal Well Drilling Fluid In Yanchang Oilfield Luopangyuan District

Luopangyuan district belongs to complex area of Yanchang oilfield drilling horizontal well.In this area the formation lithology is complex and the pressure is abnormal, the horizontal well is deep and long, the performance of the drilling fluid is poor, which leads to the frequent accident of sticking and backing pressure. The reservoir porosity and permeability are low, and the water lock effect is serious, leading to difficulties in oil and gas production, these problems have seriously restricted the oil and gas development in the region. In order to reduce downhole accidents, improve ROP, enhance oil recovery, a potent inhibition studies, high lubricity and can protect the reservoir in horizontal well drilling fluid is important.Firstly, through a lot of drilling data research, analysis of the causes of the accident, through field sampling investigation and analysis of Luopangyuan districrt geological conditions, identified the mainly problem of drilling fluid, clearly the drilling fluid system optimization direction. Based on multi-port well sampling, completed the main optimization of treatment agent. For major complex issues in the region, completed the development of the anti-temperature polymer fluid loss additive, the efficient lubricant and the waterproof lock agent.For different performance requirements of drilling well in different segments, by treating agent complex and performance evaluation, completed the formulations optimization of the KPAM polymer drilling fluid system, and completed a field application test in Luoping 16 well in Yanchang oilfield Luopangyuan districrt. The results show that the system has strong inhibition ability and good lubrication performance, the field construction process is smooth and no backing pressure, completion rate in the area leading level. Indoor dynamic reservoir permeability recovery tests show that the system reservoir permeability recovery above 90%, has the very good reservoir protection effect.Through the laboratory study, completed a set of formula optimization of cationic emulsion polymer drilling fluid system, and compared with the performance of the KPAM polymer drilling fluid system. Results show that the rheological properties of cationic emulsion polymer drilling fluid system is good, inhibition and lubrication performance is superior to KPAM polymer drilling fluid system, and has more advantages in the horizontal well drilling.