Application of Air Percussion Drilling Improves Drilling Efficiency in Horizontal Sandstone Wells

Abstract

EQT Production has implemented a new technique for drilling horizontal wells in the hard formations of the Appalachian Basin.Air percussion drilling has been adopted for use horizontally in the Berea sandstone, a hard and abrasive sandstone reservoir that had been traditionally drilled with roller cone bits. The evolution of the technology started with a packed-hole assembly that was trialed on three wells using stabilizer placement to provide directional control in the horizontal. The results were promising as penetration rates increased, but many trips were required to keep the wellbore in the desired target zone. To improve directional control, a percussion BHA with a bent housing positive displacement motor (PDM) was implemented. The introduction of the positive displacement motor with the air hammer produced the same penetration rates seen in the packed-hole assembly while providing the directional control needed. Since mid 2009, the PDM percussion assembly has become the standard practice for drilling Berea horizontal wells, replacing the roller cone BHA. Through June 2010, over 40 wells have been drilled using the assembly. The lateral portion for a majority of the wells is now drilled in one run, reducing total drilling time from 22 to 13 days, dry hole costs by over one half and total well costs by about one third.

Rotary - percussion drilling method - historical review and current possibilities of application

“…section it was found that the costs of this action decreased by 50%. This cost reduction was not only connected with faster ROP, but also with using nitrogen as a circulating mediumwhat overcame the risk of ignition [7]. Generally, the cost of making drilling wells were decreased by 30%, what is shown in the chart on the Figure 7.…”

Investigation of Old Exploration Boreholes in the Lublin Basin with Regard to Potential Rotary-Percussion Drilling of Shale Gas Wells

“…In the Berea region, until mid-2010, 3000-4000 feet (914-1220 m) deep boreholes were being drilled using the rotary-percussion method. The use of the drilling method was a major success since the total cost dropped by one-third, and the drilling time decreased by half in comparison to the conventional method [45].…”

Optimum energy calculation for a drill hammer-blow RH571-4W

“…Usually, the perforator, containing an alternative hammer, is placed outside the hole. The mode of percussion drilling is very widespread during the exploitation of ore deposits [7].…”