大孔道高渗层开采后期封堵技术

Plugging technologies used in the late production period of highpermeability layers with large pore paths

大庆油田喇嘛甸区块储层大多为高渗透油层,随着注采的深入,陆续变化为大孔道高渗层,这类油层在钻井中易造成钻井井漏、钻井液滤液伤害储层,采油过程中易出现低效循环或无效循环等问题。为解决井漏和钻井液伤害储层问题,研制了以成膜聚合物、可降解颗粒和天然纤维为主要成分的锁孔成膜封堵剂,通过锁孔成膜封堵剂的室内加量优选实验、性能配伍实验,得到了锁孔成膜封堵剂在钻井液中的加量为2%~3%,确定了钻井液配方为:2%膨润土+0.5%HX-D阳离子聚合物抑制剂+1%阳离子黏土稳定剂NW-1+1.5%井壁稳定剂FRJ-Ⅱ+0.5%HPAN+1%改性沥青+0.2%氢氧化钾+2%~3%锁孔成膜封堵剂,形成了钻井过程中的锁孔成膜防漏封堵技术,现场应用过程中防漏成功率提高了9.3%,钻井液侵入带平均厚度由原来的29 mm降至5 mm,有效保护了储层。为解决采油过程中低效循环或无效循环问题,研制开发了以油泥砂为主剂的一种堵水调剖剂,通过堵水调剖封堵物强化时间与最终强度实验,确定了堵水调剖悬浮液中油泥砂与胶结剂的比例为20∶1、胶结剂的质量分数为5%,设计了现场堵水调剖技术方案以及应用要点和注意事项,在现场试验4口井,含水最大降幅为7.0%,累计增油837 t。该封堵技术有效解决了大孔道高渗层开采后期钻采过程中出现的上述各种问题,为大孔道高渗层后期的顺利钻采提供了技术保障。

The reservoirs in the Lamadian Block of Daqing Oilfield are mostly high-permeability oil layers,and they successively change into high-permeability layers with large pore paths as injection and production go on.In this type of oil reservoirs,mud loss and reservoir damage caused by drilling fluid filtrate tend to happen in the process of drilling and low-efficiency or inefficient circulation tends to occur in the process of oil production.In order to solve mud loss and reservoir damage caused by drilling fluid,this paper researched and developed the pore locking and film forming based plugging agent which is mainly composed of film forming polymer,degradable particle and natural fiber.Then,laboratory dosage optimization experiment and property compatibility experiment were carried out on the pore locking and film forming based plugging agent.It is shown that its dosage in drilling fluid is 2%-3%.The formula of drilling fluid is determined to be 2%bentonite+0.5%HX-D cationic polymer inhibitor+1%cationic clay stabilizer NW-1+1.5%borehole stabilizer FRJ-II+0.5%HPAN+1%modified bitumen+0.2%potassium hydrate+2%-3%pore locking and film forming based plugging agent.The pore locking and film forming based plugging and mud loss prevention technology used in the process of drilling is formed.Its field application increases the success rate of mud loss prevention by 9.3%,decreases the average thickness of drilling fluid invaded belt from 29 mm to 5 mm and protects the reservoirs effectively.In order to solve the low-efficiency or inefficient circulation in the process of oil production,a kind of water plugging and profile control agent with oily sludge as the main composition was researched and developed.Strengthening time and final strength experiment was conducted on the plugging materials for water plugging and profile control.And it is accordingly determined that the ratio of oily sludge to cementing agent in the suspended liquid of water plugging and profile control agent is 20∶1 and the mass fraction of cementing agent is 5%.In addition,the technological scheme of field water plugging and profile control and its application highlights and considerations were designed.Among four field test wells,the maximum decline amplitude of water cut is 7.0%and the cumulative oil increment is 837 t.In conclusion,this plugging technology effectively solves above-mentioned problems which occur in the drilling and production stage of high-permeability layers with large pore paths in the late production period and provides the technical support for the smooth drilling and production of high-permeability layers with large pore paths in the late period.