低汙損鑽井技術研究

The Study of Reducing Formation Damage Drilling Technique

王文烈(Wen-Lieh Wang)

地層污損 ； 控壓鑽井 ； 鑽入泥漿 ； formation damage ； managed pressure drilling ； drill-in mud

臺灣鑛業

66卷1期（2014 / 03 / 01）

1 - 9

繁體中文

鑽井作業時，常因鑽井泥漿、濾液或鑽鑿固粒等侵入生產層，造成地層污損，改變了生產層的特性，導致生產率降低。特別是低壓地層的鑽井作業，因為差壓的增高，更需特別留意地層污損的預防。負壓鑽井技術中以泡沫鑽井及充氣泥漿鑽井技術較普遍，因為泡沫鑽井比空氣鑽井所需能量較小，不需較高的環孔流速，較不會產生沖蝕的問題；充氣泥漿鑽井技術具有比重可自由調整、無漏泥不循環現象與避免差壓黏卡等卡鑽意外事件之優點。控壓鑽井所需之鑽井作業安全工作窗（Drilling Window；指鑽遇地層其破裂壓力與地層壓力之差距）較超壓鑽井小，亦即較不會發生漏泥或噴井等事故。在挪威北海大陸棚「Mandarin East」井應用控壓鑽井技術，共節省7,500,000美元（S.K. Naesheim et al., 2011）。控壓鑽井技術在鑽井時能夠分辨生產力較佳的生產層，且能降低鑽井流體對儲集層之污損，進而提高生產率。在低污損泥漿評估方面，鑽入泥漿（Drill in mud鑽入儲油層時所用之泥漿）系統確實具有較佳的抗地層污損效果，但相較於PHPA系統，其卻具有較高的黏度與較低的水泥污容忍度，因此建議未來下水泥前應先置換回PHPA泥漿，以防止泥漿材料之耗費。由基本性質試驗、水泥污容忍度試驗、地層污損試驗與成本分析，PHPA泥漿系統與鑽入泥漿系統之綜合評估結果，鑽入泥漿系統具有較佳的抗地層污損能力，但單位成本較高，且水泥容忍度低，下水泥前需先置換泥漿，以避免泥漿材料之耗費。

In order to reduce the occurrences of formation damage, we must discuss the compatibilities between mud and various additives, operation factors of drilling and completion. The most effective way to reduce formation damage is the prevention, and it's also the most cost-effective way.Conventional drilling techniques often encounter fluid loss and formation damage. Recently, global oil industry has adopted the managed pressure drilling (MPD) to solve the problems that mentioned above. Besides, in order to increase oil and gas reserves, CPC Taiwan has drilled several wells in Hsinchu-Miaoli area in Northwestern part of Taiwan and in mudstone area of Southern part of Taiwan for the past few years. During drilling of these wells either borehole instability or formation damage were encountered, which cause a lot of troubles of drilling. This caused a huge loss in investment. Therefore, it is very important to reduce the formation damage. By achieving that the cost and risk can be reduced and hence increase the efficiency.This paper performed the prevention of formation damage and the underbalanced drilling, managed pressure drilling and the low damage mud to reduce the formation damage caused by drilling and to improve the production rate.