疏松砂岩复杂压力储集层保护技术

渤海某油田经过多年注水开发,疏松砂岩储集层呈现局部压力系数低、层间差异大的特点,储集层保护难度大。目前国内外针对疏松砂岩储集层出砂机理及防砂措施研究较多,而针对疏松砂岩复杂压力体系调整井钻井液及钻井优化技术研究不足。基于此,针对该油田开发情况,结合疏松砂岩和地层压力复杂的特点,开展了储集层伤害机理研究,利用室内实验进行了钻井液体系优化研究并优化设计了钻井施工工艺。结果表明:钻井阶段储集层损害的主要原因为黏土吸水膨胀、外部或内部固体颗粒运移堵塞孔喉或孔隙导致渗透率降低,以及施工工艺不完善等;使用胺基硅醇、LPF-ZP-HTC复配能提高钻井液的抑制性和封堵承压能力;并通过施工工艺的优化研究,形成了一套疏松砂岩复杂压力储集层保护技术。渤海油田现场试用情况表明,该技术的应用能够实现易造浆井段的流变稳定、提高起钻速率、缩短建井周期及提高单井产量。

PROTECTING TECHNIQUE FOR THE RESERVOIRS WITH UNCONSOLIDATED SANDSTONE AND COMPLEX PRESSURE

After many years' waterflooding development of one oilfield in Bohai,the unconsolidated sandstone reservoirs have the characteristics of low local pressure coefficient and great inter-layer difference,therefore the reservoir protection is very difficult.Nowadays,the sand produced mechanisms and sand controlling measures of this kind of the reservoir at home and abroad were researched a great deal,while few people studied on the adjustingwell drilling fluid and drilling optimizing technique for the unconsolidated sandstone and complex pressure system.On the basis of the above,in the light of the developed conditions of the oilfield,integrating with the two characteristics stated above,the reservoir damage mechanisms were figured out,and moreover with the help of the indoor experiment,the drilling fluid system was optimized and the drilling operation technologies was optimally designed.The study achievements show that the main reasons of the reservoir damage result from the clay water swelling and solid particles no matter the external and internal migration blocking the throats and pores,and finally the permeabilities are decreased and moreover the operational technologies are not perfected and so on;the inhibitive property of the drilling fluid and pressure bearing capacity can be improved by adding HAS and LPF-ZP-HTC,and furthermore,by means of the studied optimization of the operation technologies,a set of the reservoir protecting techniques were developed for the unconsolidated sandstone and complex pressure reservoirs.The field test of Bohai Oilfield shows that the application of the technique can realize the rheological stability of the slurry-yield well section,increase the lifting rate,shorten the drilling period and improve the production of the individual well.