密閉取芯技術

密閉取芯技術

Sealed coring Technology

油田勘探開發(fā)需要準確獲得油層原始含油飽和度和地層孔隙度等地質(zhì)資料，以制定合理的方案。對于注水開發(fā)的老油田，需要檢查注水效果，定量分析油層油水動態(tài)、水淹油層情況及水驅(qū)油效果，制定出有效的挖潛增效增產(chǎn)措施，完善開發(fā)方案。這些都需要以巖性分析資料為依據(jù)。

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.

密閉取芯是指在水基鉆井液中取得的巖芯基本不受鉆井液污染，能真實再現(xiàn)地層原始地質(zhì)孔隙度、含油飽和度及含水率等資料。它是通過專用密閉取芯工具和密閉液的共同作用來實現(xiàn)的一種特殊鉆井取芯工藝。

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.

工藝原理：取芯開始前，在井口將取芯工具內(nèi)筒里注滿密閉液，內(nèi)筒下端由銷釘固定密封活塞，上端由浮動活塞密封，形成密封腔。取芯鉆進時，由于鉆壓的作用，銷釘被剪斷，密封活塞上行，內(nèi)筒密封被打開之后，取芯鉆頭接觸井底，并迫使密封活塞完全進入內(nèi)筒。此時內(nèi)筒里的密閉液開始被擠出，在井底形成保護區(qū)。鉆進過程中，巖芯不斷形成和增長，推著活塞不斷上行。由于內(nèi)筒上端是密封的，故筒內(nèi)密閉液只能被進入內(nèi)筒巖芯所擠壓，且只能從內(nèi)筒環(huán)空間隙等體積向外排出，排出的密閉液立即涂抹在巖芯柱表面形成保護膜。同時在井底巖芯柱周圍形成保護區(qū)，鉆井液只通過鉆頭水眼和外泄水槽循環(huán)，在攜帶巖屑和清洗冷卻外唇面，使保護巖芯免遭鉆井液污染的目的得以實現(xiàn)。

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.