This paper was prepared for presentation at the AADE 2004 Drilling Fluids Conference, held at the Radisson Astrodome in Houston, Texas, April 6- 7, 2004. This conference was sponsored by the Houston Chapter of the American Association of Drilling Engineers. The information presented in this paper does not reflect any position, claim or endorsement made or implied by the American Association of Drilling Engineers, their officers or members. Questions concerning the content of this paper should be directed to the individuals listed as author/s of this work. Abstract The traditional practice of monitoring moving pickup and slackoff weights as an indicator of hole conditions may not provide sufficient early warning of deteriorating wellbore conditions. Recent studies conducted by two different operators demonstrate that the pickup weight as the pipe comes off the slips should be monitored as closely as the traditional pickup weight measurements that are taken as the midpoint of the stand passes through the rotary. While moving pickup and slackoff weights may appear to be within predicted tolerances, the initial force required to get off the slips may increase over time, especially in extended-reach wells. This paper demonstrates why the trend in off-slips weights at the pickup point should be considered a key indicator of hole-cleaning and sweep effectiveness. The three case histories presented are supported by graphical data comparing pickup point and mid-point measurements as they relate to actual downhole conditions. In the first case, a Eugene Island well with a 45° deviation was abandoned after t hree sidetracks characterized by several pack-offs and stuck pipe incidences were drilled. Post-well analysis revealed a distinct trend of increasing pickup weights, while the mid- point weights remained consistent. In the second and third cases, the pickup weight trend observed while drilling a 50° onshore well and a 38° well in Texas state waters indicated that hole conditions were deteriorating. An investigation revealed that the weighted sweep program had not been properly implemented. The correct application of weighted sweeps remedied the problems, as reflected in the subsequent pickup weights. Both mid-point and off-slips weights should be captured as effective indicators of developing wellbore management issues. In addition, best practices related to hole cleaning should be implemented to help maximize the effectiveness of the recommended sweep program. Introduction Years of experience indicate “a well will talk to you and tell you what it needs.” Correct interpretation of what the wellbore is “saying” is critical; misinterpretation, at a minimum is usually costly and can be disastrous in the extreme. For example, a “sticky” hole may be the result of a balled bottomhole assembly (BHA), sensitive shales, a poor quality filter cake, high differential pressures, plastic shales, a complex directional plan, or silt and cuttings bed buildup. Even though the various causes of a sticky hole are in one way or another related to the mud system, their treatments are quite different. A timely and correct diagnosis, resulting in the proper remedial actions, is vital to the drilling operation. Traditionally, our industry has used the spread between pickup and slackoff weights as a primary indicator of hole conditions . Commonly these weights are taken with the pipe moving when the weight indicator movement is least erratic, which is usually as the mid- point of the stand passes through the rotary. However, closer observation may reveal a new perspective on these measurements . Experience drilling mod erate to complicated deviated wells shows the initial off-slips weight is usually greater than the pickup weight and the initial breakdown weight is usually less than the slackoff weight. While the conventional pickup and slackoff weights may fall within the predicted torque and drag limits, initiation of drillstring movement requires more energy than anticipated, often necessitating rotation off- slips to move the pipe. Discussions of these observations led to the practice of recording and plotting both off-slips weight and moving pickup weight for each stand during trips on three wells where hole cleaning and silt-bed removal were especially critical because of the wellbore geometry and the directional plan. These plots demonstrated a correlation between the off-slips pickup weight and the effectiveness of the hole-cleaning procedures used on the well. Moving pickup weights exhibited little variance from trip to trip, regardless of whether the hole was “clean,” or whether it was “dirty” and hole conditions were deteriorating. The initial off- slips weight however, exhibited a relatively constant variance to moving pickup weight when the hole was considered clean, but exhibited a marked and increasing divergence as the wellbore became dirty and hole conditions began to deteriorate. Misdiagnosis of the AADE-04-DF-HO-41 Monitoring Initial Off-Slips Weight Provides Early Warning of Hole-Cleaning Deficiencies Michael Ray Sewell, Newfield Exploration; Javier Arellano and Leroy Kuhn, Manti Operating Company; Joe Billingsley, Baroid product service line, Halliburton

Monitoring Initial Off-Slips Weight Provides Early Warning of Hole Cleaning Deficiencies

Download PDF Report

Upload
ronald-landry
View
219
Download
0

Embed Size (px)

Citation preview