Case History of Unique Dual Cutting Eccentric Reamer to Address Poor Wellbore Condition While Reducing NonProductive Time in Drilling Operation Indonesia

Abstract

Historically the main focus of cost reduction and drilling improvement exercises has been to focus on reducing on-bottom time by improving ROP and drilling entire hole sections with a single bit. This has been so successful that in most cases only minor additional improvements are available and the potential cost reductions are much smaller. However, there has been less attention on reducing the time when the bit is not on bottom such as trips, wiper trips, backreaming, etc. When this time is analyzed in detail it becomes apparent that much of it is spent improving the quality of the wellbore to facilitate tripping and running casing or liner. This is where significant savings can still be made and such simple tool need to be added in the BHA to address the wellbore conditioning issue.

The paper discusses some cases of drilling operation in Indonesia where the hole sections are considered challenging such as Pipe stall, overpull, stuck pipe, and tight spots that are typically experienced during drilling and tripping. It also results in difficult trip-out BHA and subsequent trip-in with casing.

A unique dual cutting eccentric reamer tool was introduced to help to improve the wellbore quality. The tool removes or smooths out irregularities in the wellbore geometry during drilling and reaming operations. After several case, the tool solved many cases of wellbore condition issues. In one of west java drilling operation, the time savings in pulling out of hole was improved by average 78% in the 12¼-in. section and average 45% in the 17½-in. While in delta mahakam drilling operation, the tripping speed of the BHA is improved from average 82 m/hr to 192 m/hr (or about 139% improvement). In addition to that, the tool has also solved some cases to facilitate tripping in casing to designated depth. Ultimately, the tool has added a new capability for drilling improvement and optimization through wellbore conditioning, removing risk of pipe stuck, reducing non-productive time and interval costs which ultimately contributes to lower drilling cost.