密闭取芯技术
密闭取芯技术
Sealed coring Technology
油田勘探开发需要准确获得油层原始含油饱和度和地层孔隙度等地质资料，以制定合理的方案。对于注水开发的老油田，需要检查注水效果，定量分析油层油水动态、水淹油层情况及水驱油效果，制定出有效的挖潜增效增产措施，完善开发方案。这些都需要以岩性分析资料为依据。
Oil field exploration and development need to obtain the original oil saturation and porosity and other geological data, in order to develop a reasonable solution. For water injection development of the old oil fields, need to check the effect of water injection, quantitative analysis oil and water dynamics and water flooded reservoir and water flooding effect, work out effective potential for increasing production and efficiency measures, improve the development plan. These all need to be based on lithology analysis data.
密闭取芯是指在水基钻井液中取得的岩芯基本不受钻井液污染，能真实再现地层原始地质孔隙度、含油饱和度及含水率等资料。它是通过专用密闭取芯工具和密闭液的共同作用来实现的一种特殊钻井取芯工艺。
The core is the core of the water - based drilling fluid, which is not contaminated by the drilling fluid, and can reproduce the original geological porosity, oil saturation and water content. It is a kind of special drilling core technology, which is realized by the joint action of the special sealed coring tool and the sealing fluid.
工艺原理：取芯开始前，在井口将取芯工具内筒里注满密闭液，内筒下端由销钉固定密封活塞，上端由浮动活塞密封，形成密封腔。取芯钻进时，由于钻压的作用，销钉被剪断，密封活塞上行，内筒密封被打开之后，取芯钻头接触井底，并迫使密封活塞完全进入内筒。此时内筒里的密闭液开始被挤出，在井底形成保护区。钻进过程中，岩芯不断形成和增长，推着活塞不断上行。由于内筒上端是密封的，故筒内密闭液只能被进入内筒岩芯所挤压，且只能从内筒环空间隙等体积向外排出，排出的密闭液立即涂抹在岩芯柱表面形成保护膜。同时在井底岩芯柱周围形成保护区，钻井液只通过钻头水眼和外泄水槽循环，在携带岩屑和清洗冷却外唇面，使保护岩芯免遭钻井液污染的目的得以实现。
Process principle: core before the start, at the wellhead will take tool core tube filling sealing fluid, the lower end inside the cylinder by the pin fixed sealing piston, the top by floating piston seal, forming sealing cavity. Core drilling, due to the role of drilling pressure pin is cut, the sealing piston upward, inner cylinder seal is opened, coring bit touching the bottom of the well and forced sealing piston fully into the inner cylinder. At this time, the inner cylinder of the confined liquid began to be squeezed out, in the bottom of the formation of protected areas. In the course of drilling, the core of the core is continuously formed and increased, and the piston is pushed up. Due to the upper end of the inner tube is sealed, so inner cylinder closed solution can only be entered in core barrel extrusion and can only be discharged from the cylinder annular clearance volume outside, airtight liquid discharged immediately smear form a protective film on the surface of the rock core columns. While forming a protection zone around the rock bottom column and drilling fluid only by bit nozzle and leakage of circulating water channel, in carrying cuttings and clean the cooling outer lip surface to protect core to avoid contamination of drilling fluid can be achieved.