An approach for wellbore failure analysis using rock cavings and image processing  

作　　者：Christopher Skea Alireza Rezagholilou Pouria Behnoud Far Raoof Gholami Mohammad Sarmadivleh 

机构地区：[1]Department of Petroleum Engineering, Curtin University [2]Department of Petroleum Engineering, Amirkabir University of Technology

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2018年第5期865-878,共14页岩石力学与岩土工程学报（英文版）

摘　　要：There have been interests to link different cuttings/cavings to various wellbore failure types during drilling. This concept is essential when caliper and image logs are not available. Identification ofwellbore failure during drilling gives more chance of immediate actions before wireline logging program. In this paper, an approach was presented based on the image processing of ditch cuttings. This approach uses the sphericity and roundness of cuttings as input data to classify caving types and subsequently deter- mine the dominant failure type. Likewise, common definitions of cavings were discussed initially before a new criterion is suggested. This quantitative criterion was examined by observations from caliper and acoustic image logs as well. The proposed approach and criterion were implemented on ditch cuttings taken from a well in Western Australia. Results indicate that the primary failure is shear failure （breakout） due to high levels of angular cavings. However, another failure due to the fluid invasion into pre-existing fractures was also recorded by blocky cavings.There have been interests to link different cuttings/cavings to various wellbore failure types during drilling. This concept is essential when caliper and image logs are not available. Identification ofwellbore failure during drilling gives more chance of immediate actions before wireline logging program. In this paper, an approach was presented based on the image processing of ditch cuttings. This approach uses the sphericity and roundness of cuttings as input data to classify caving types and subsequently deter- mine the dominant failure type. Likewise, common definitions of cavings were discussed initially before a new criterion is suggested. This quantitative criterion was examined by observations from caliper and acoustic image logs as well. The proposed approach and criterion were implemented on ditch cuttings taken from a well in Western Australia. Results indicate that the primary failure is shear failure （breakout） due to high levels of angular cavings. However, another failure due to the fluid invasion into pre-existing fractures was also recorded by blocky cavings.

关 键 词：Caving shape CUTTINGS DRILLING Image analysis Wellbore failures ROUNDNESS SPHERICITY 

分 类 号：TE28[石油与天然气工程—油气井工程]