Pars Drilling Fluids Company has developed a new low cost technology Additive to prevent bit balling in Marl and Sticky Clay formations specifically for top hole sections. BIT-WASH is a specially formulated product designed to rapidly remove problematic clays surrounding the bit and the BHA and increases significantly the ROP in previously troublesome sections. It provides a prolonged low cost solution to sections which have previously disrupted drilling operations and increased costs.

A case study of pumping BIT-WASH pills verified the ROP enhancement in a problematic oil field in the south of Iran that had encountered bit balling challenges, particularly in the 17.5” hole section, which contains highly reactive clays in Aghajari and Mishan formations. BIT-WASH pills were prepared as 1.5 % V/V of the additive to pre-treated drill water and pumped in two Stages. Treatments were very successful, with the first 50 bbl pill pumped at a depth of 592 meters followed by the second application of 30 bbl at a depth of 611 meters. A history of slow drilling rate had been observed in these sections with a much lower historical ROP. Pumping the first pill quickly resulted in a significant change in drilling rate with over 50% increase from 6 to 9.5 (m/hrs). This having a direct impact on time saved and also the cost involved. Table 1 below shows the drilling parameters before and after BIT-WASH pill pumping:

Time (hrs)	Operation	Drilled Depth (m)	Avg. RPM	Avg. Torque (Klbs)	Avg. WOB (Klbs)	Avg. ROP (m/hrs)
3.5	Drilling before pumping BIT-WASH pill	20	115-120	6	36	6-6.5
2	Drilling after pumping first BIT-WASH pill	17	125	7	42	8
3	Drilling after pumping second BIT-WASH pill	34	128	6.7	35	9-9.5

Figure 1

Performance Evaluation

In the evaluation of the low cost performance pill, the instant and average ROP are shown in the graphs below. From Table 1, WOB, Torque, and RPM did not change drastically during the drilling of these intervals, and were in a narrow range. The average ROP before pumping the pill was 6-6.5 m/hrs and increased steadily to reach 9.5 m/hrs. BIT-WASH pill increased ROP in the targeted 50-100 meter interval.

Figure 1 highlights the success of pumping a secondary low cost pill of BIT-WASH.

ROP reduced to 4.4 m/hrs after 3 hours from the initial leap observed. This indicating a 30% reduction of ROP and with the pumping of a second smaller low cost pill the ROP jumped back to previous levels of over 10 m/hrs.

Graph 1 below highlights clearly average ROP changes during drilling, and the ROP trend with the improvement quickly observed after pumping the initial pill and the maintenance over a longer period on the application of the secondary low cost smaller pill:

 Figure 2 highlights  the changes of instant ROP and shows the advantages BIT-WASH pill’s have on the effect of increasing ROP in a 15-minute time interval and how this simple treatment can reduce costs and improve drilling operations.

For more information regarding the product, system or process mentioned in this paper, you can contact PDF’s Technical and R&D Department at info@parsdrill.com .