In 2013 Horizon Mud Company was selected by an operator in Upton County. The well plan was to drill 3 wells setting 500’ of surface, 8900’ intermediate, and drill a middle Wolfcamp horizontal out to 14,000’ TD/ 9414’ TVD. As we drilled the intermediate hole on well #1 we encountered severe losses in the Clearfork formation. Extremely aggressive LCM was pumped with minimum success. Below are well summaries of advancements that were made between well #1 through well #3.

Well #1

17 ½” surface hole- drilled with fresh water and gel sweeps

12 ¼” intermediate hole- drilled with brine water to 4500’ sweeping hole with pre-hydrated fresh gel at 60 sec/1000 cc. At 4500’ the hole was displaced with Horizon Chemical Mud which is built with soda ash, bentonite, desco, & PHPA. This system was selected for this hole section for its tight wall cake that has been proven to have benefits for reducing washout, increased rop, & higher cement tops. At a depth of 5600’ total losses were experienced multiple 15 ppb LCM pills were pumped increasing up to 50 ppb, gaining returns periodically. This continued for 9 days until hole section was TD’d.

8 ½” horizontal hole- drilled curve with brine water while pumping x/c sweeps. Sweeps were retained to achieve full mud properties by EOC. Mud weight was then increased to 10.8ppg and drilled to td with no problems.

Total losses- 20,000 bbl

Days on well- 36

Final well cost-$314,000.00

What we learned: With the losses encountered, we did not see the need to continue to build volume using desco. We discussed going to a lignite system, giving comparable rheological results with a reduction in price per bbl. In doing this, we also decreased the ppb of bentonite, which lowered our viscosity by a few seconds per 1000 cc. Both decisions were made to offset the large losses encountered on the intermediate hole section.

Well #2

17 ½” surface hole- drilled with fresh water and gel sweeps

12 ¼” intermediate hole- drilled with brine water to 4100’ sweeping fresh gel 60 sec/1000 cc. At 4100’, hole was displaced with gel/lignite mud system, which was built with soda ash, gel, lignite, & PHPA. This system has similar rheological properties to the HCM system. At 6300′ full returns were lost. Crews bypassed shakers, added LCM into the system, and began pumping 30 ppb pills every 90’. Drilled ahead to TD with 80-90% returns.

8 ½” horizontal hole- displaced with the same brine polymer mud from well #1 that we had stored in frac tanks. Drilled ahead to TD maintaining 10.5 ppg with no hole problems.

Total losses-4600 bbl

Days on well-28

Final well cost-$206,500.00

What we learned: It was proven that with lower gel concentrations and the cheaper dispersant, losses were drastically reduced. We still felt we could achieve better results. Before spudding the third well, we met with the drilling engineer again and recommended displacing later, due to the fact that the losses that were encountered were 1500’ after displacement. The idea was to cut 1 to 2 days off of mud. It was agreed that the third well would be displaced at 5200’. We also discussed mudding up the reserve, due to the high volume of mud losses on well #1 & 2. We again reduced the price per bbl by reducing the ppb of lignite.

Well #3

17 ½” surface hole- drilled with fresh water and gel sweeps

12 ¼” intermediate hole- drilled with brine water to 5200’, sweeping the hole with pre-hydrated fresh gel at 60 sec/1000 cc. At 5200’, the hole was displaced with gel/lime/lignite system circulating the reserve pit. No losses were encountered from displacement to TD.

8 ½” horizontal hole- displaced with the same brine polymer mud from well #1 that we had stored in frac tanks. Drilled ahead to TD maintaining 10.0 ppg with no hole problems.

Total losses- 0

Days on well- 23

Final well cost- $90,000.00

What we learned: By displacing at 5200’, we experienced a 30 % increase in average ROP, limiting the time spent in the loss zones. The increased circulating volume helped crews manage mud weight and properties more effectively. By doing so, you can see the progression made in three wells drilled saved $200,000.00 in mud costs and 13 days of rig time. We have continued to work for this operator on multiple rigs, showing comparable results due to our ability to think outside the box and find a way to increase performance and lower mud cost.