Single-stage spacer pill additive helps break free stuck drillstring

DeepClean pill additive enables efficient, cost-effective extraction

Location

Malaysia, Asia, Offshore

Summary

Using DeepClean™ single-stage spacer pill additive, an operator in Malaysia extracted a differentially stuck drillstring within timeline and financial constraints.

Objective

Free differentially stuck drillstring

The operator needed an efficient, cost-effective way to extract a differentially stuck drillstring while handling personnel constraints related to COVID-19 mandates.

Drilling challenges

While drilling a reservoir section, the driller tried to pull out of the hole at 13,871 ft because of a logging-while-drilling tool failure. While pulling out of the hole, the drillstring became stuck at 11,267 ft. With the inability to rotate and move the drillpipe while being able to circulate at 400 galUS/min with 1,650 psi, the drillpipe was differentially stuck. The differential pressure when stuck was 830 psi. The well’s angle was 87°, and for this section, it was a tangent from 95/8-in casing shoe (10,280 ft) until the well’s total depth.

Below is the timeline of the unsuccessful attempts to free the stuck pipe:


1	Jarred up to 30,000 lbf.ft overpull with no success.	2 h
2	Continued jarring up to 30,000 lbf.ft. Attempted to rotate the pipe with torque limit set at 30,000 lbf.ft with no success.	3 h
3	Pumped 85 bbl of base oil to create reduction of 388 psi in hydrostatic pressure in the annulus. This was spotted under the BOP.	1.5 h
4	Continued jarring.	4.5 h

Results

On the right, filtercake after submitted to soaking in DeepClean pill additive.

(Left) Filtercake obtained in ceramic disk of same pore throat of formation. (Right) Filtercake after submitted to soaking in DeepClean pill additive.

Important factors to free drillstring

Laboratory development and testing of the DeepClean pill additive formulation to find the optimal concentration before it was included in the drilling fluids program.
Low fluid loss and thin filtercake for VERSAPRO system throughout the drilling. The VERSAPRO system HTHP fluid loss was maintained between 2.6 and 2.8 mL/30min, and the filtercake size was observed by the relatively short soaking time with the DeepClean pill additive before the pipe was set free.