Performance Report: Pakistan: Conqor 404 Prevents Severe Drill Pipe Corrosion in Deep Well

Challenge: As with most wells, M-I SWACO uses corrosion coupons during this particular project to monitor the corrosion rate while drilling to ensure it remains under an acceptable limit (<2 lb/ft2/yr). An analysis of the first coupon installed in the HWDP – DP tool joint yielded a very high corrosion rate (>30 lb/ft2/yr), which was totally unacceptable.

Solution: The operator accepted the M-I SWACO recommendation to use CONQOR 404 corrosion inhibitor, and to maintain the system pH at or above 10.5.

Result: The results obtained were quite extraordinary. The corrosion rate dropped below the minimal acceptable range, which ultimately allowed the client to:

  • Increase in life of drill string and drill string components by minimizing damage caused by a high corrosion rate
  • Preventing formation of scale inside the drill pipes and drill collars, which could plug the bit, MWD tool and / or mud motor resulting in stuck pipe and / operational downtime
  • Besides reducing the corrosion rate, the high pH also helped reducing the fermentation of polymers, thus minimizing the concentration of bactericides

A Pakistan oilfield operator and one of the largest national oil and gas exploration company of Pakistan faced corrosion issues in their drilling campaign. The operator was drilling the appraisal well, Domial-2 with TD 15,500 ft MD (4,724 m). This Potwar region is considered to be very challenging for drilling; handling losses and high pressure water kicks are quite common in this region.

While drilling 17 ½ in. section M-I SWACO ran a corrosion coupon. After exposing the ring for 216 hours the analysis showed a severe corrosion rate (30.15 lb/ft2/yr). The operator was briefed on the situation and agreed to immediately treat the mud system with CONQOR 404 corrosion inhibitor. The inhibitor was added and the pH raised and was maintained around 10.5. After the treatment the results showed dramatic decrease in corrosion rate to <2 lb/ft2/yr.

Download: Pakistan: Conqor 404 Prevents Severe Drill Pipe Corrosion in Deep Well (0.62 MB PDF)

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“While drilling a deep well for one of our national clients, a Pakistani Oilfield Operator, a severe corrosion problem was observed (corrosion rate = 30.15 lb/ft2/yr). The client accepted our recommendation to raise the pH and treat the system with 0.9 lb / bbl CONQOR 404 corrosion inhibitor to maintain pH around 10.5. After the treatment, we observed a dramatic decrease in the corrosion rate which came under acceptable limit f < 2 lb/ft2/yr.”
Zia Haider Shah
Area Engineer