威202H3平台废弃油基钻井液处理技术

Disposing Waste Oil Base Drilling Fluid from the Wei202H3 Platform

目前处理废弃油基钻井液一般采用集中填埋或回注地层,依然存在潜在的环境污染问题,同时也浪费了大量矿物油资源。笔者对威202H3平台废弃油基钻井液进行回收利用研究,首先测定了废弃钻井液本身的性质,测得其表观黏度为100~120 mPa·s、塑性黏度为80~100 mPa·s、动切力为20 Pa、初终切为20/35 Pa/Pa,粒度主要集中在5.59~13.74μm。在现场及实验室进行复配再利用研究,发现在威202H3-3井龙马溪地层加入2 m^3废弃油基钻井液后,油基钻井液终切不断升高、动塑比难以控制;利用废弃油基钻井液中劣质固相,在长宁H12-3井用于配制堵漏浆,施工顺利,效果较好。因此得出,废弃油基钻井液回收再利用的困难在于其中含有大量粒径小于20μm的固体颗粒,现有固控设备难以除去,并且现有处理技术均存在安全、占地面积、能耗、交通运输、环保及成本问题,建议这种废弃油基钻井液体系用于配制页岩地层发生漏失时的堵漏浆,在一定程度上减小经济损失。而在今后废弃油基钻井液处理技术的研究过程中,如果超临界CO_2流体萃取技术能够降低成本,将成为废弃油基钻井液重要的处理技术。

Waste oil base muds(OBMs)are disposed of presently by burial or reinjection.Potential pollution to environment and waste of large amount of mineral oil are the problems inusing these disposal methods.A study has been conducted on the recycling of waste OBMs from the Platform202H3.The waste mud had apparent viscosity of100-120mPa·s,plastic viscosity(PV)of80-100mPa·s,yield point(YP)of20Pa,and10”/10’gel strengths of20/35Pa/Pa The particle sizes of the mud lied between5.59μm and13.74μm.Studies showed that injection of2m3waste oil base mud back into the well We202H3-3,which penetrated the Longmaxi formation,the final gel strength of the oil base mud in use was increased and the YP/PV ratio became uncontrollable.Use the low quality solids from the waste OBMs,a lost control slurry(LCM muds)was prepared and successfully used in controlling mud losses occurred in the well Changning-H12-3.From these practices,it was concluded that the troubles in recycling waste OBMs lied in the large amount of particles with sizes less than20μm,which were difficult to remove with the solids control equipment currently available.Technologies currently available in disposing of waste OBMs will be faced with problems such as safety,large spaces required,energy consumption,transportation,environment protection,and cost.It is thus suggested that the waste OBMs be used in formulating LCM muds,which can be used in controlling mud losses in shale gas drilling,thereby reducing economic losses to some extent.It is also suggested that if supercritical CO2fluid extraction technology can be used in cost control,it will be an important technology in waste OBMs disposal.