LOCATION: BAKKEN, MCKENZIE COUNTY, NORTH DAKOTA
TIMING: MAY – SEPTEMBER 2017
Extremely high gas; ceramic proppant sand; V4 Pump operating at 90Hz, 85% GVF.
- Major operator suffered 2x early conventional ESP failures due to high gas; each ESP failed after just days of operation.
- Well was expected to be high gas & high sand (ceramic proppant). Operator specified a 1750 size ESP with OEMs highest specification gas handling pump and a gas separator. The 1st ESP failed in days, seized in severe up-thrust. 2nd ESP was “completely destroyed” due to repeated, persistent gas locking.
- Operator replaced the 2 previous ESPs with a V-Pump™, mid-May 2017.
- V-Pump ran continuously until replaced by rod pump due to low well pressure & inflow.
|TUBING||2 ⅞ “|
|PUMP INTAKE DEPTH||10,629ft MD; 10,619ft TVD|
|SENSOR||10,680ft TVD \ MD|
|KICK OFF POINT (KOP)||10,862ft|
|HORIZONTAL SECTION||9,200ft long|
|TOTAL DEPTH||20,738ft MD; 11,294ft TV|
|WELL TYPE||Unconventional well, fractured using ceramic proppant|
KEY SUCCESS FACTORS (ATTRIBUTED TO THE V-PUMP):
- The V-Pump operates smoothly, and without drama, easily handling the high GVF production & widely varying production conditions.
- Modelling of well flow conditions based on production test data indicates that the pump is typically operating with pump intake GVF ranging 74% – 85%, based on daily average. Minute by minute, the pump may be dealing with a wider GVF range, possibly up to 95% GVF.
- The V-Pump operation is unaffected by the back-produced ceramic proppant.
- The motor operates effectively, adequately cooled due to the operation of the pump even at the highest GVF conditions. The pump and motor are operating at 90Hz, circa 40% motor load. Shaft load (i.e. motor HP), motor Amps and drive Amps appear to reduce slightly as the pump set speed is increased. That is consistent with V-Pump operation at other wells.
- Two previous conventional ESPs both failed after very short runs.
- Pumps were both 1750 sized main pump with the OEM’s highest specification of gas handling pump at intake and fitted with a gas separator. Both pumps still gas locked repeatedly and suffered a great many trips. The 1st ESP failed in up-thrust, the pump was completely seized and “destroyed.” The 2nd pump gas locked repeatedly, suffered 30 or 40 trips in just a few days and it too was “destroyed.”
- The well flows naturally but dies quickly due to unstable inflow and unstable wellbore flow regime. It was expected that this well would be high gas, GOR = 2,400scf/bbl, as specified at design. During recent operations (August 2017), the measured GOR has ranged from a low of 9,495scf/bbl to a high of 21,916scf/bbl, average for the period 14,720scf/bbl.
WHAT HAS BEEN THE EXPERIENCE?
Two previous conventional ESPs both failed after very short runs. Pumps were both 1750 sized pumps with the OEM’s highest specification of gas handling pump and fitted with a gas separator. Both pumps gas locked repeatedly and suffered a great many trips.
- The 1st ESP failed in up-thrust, the pump was completely seized and “destroyed.”
- The 2nd pump gas locked repeatedly, suffered 30 or 40 trips in just a few days and it too was “destroyed.”
- The 160 stage V4 pump was installed mid-May and operated trouble free for 4 months.
WELL PERFORMANCE & GOR
The well only has intermittent natural flow capability; it dies quickly and suddenly due to unstable inflow and unstable wellbore flow regime. It was expected that this well would be high gas:
- The GOR specified at application design was 2,400scf/bbl. That was considered a ‘high GOR.’
- The GOR experienced by the 1st 2 conventional ESPs ranged from 1,800scf/bbl – 6,000scf/bbl.
- Since these early conventional ESP failures, the well has been producing continuously using a V4 V-Pump, installed May 15, 2017. GOR at V-Pump start-up was 5,000scf/bbl and increased steadily. During operations in August, 2017 the measured GOR has ranged from a low of 9,495scf/bbl to a high of 21,916scf/bbl, average over the period 14,720scf/bbl.
- The V-pump has operated smoothly and effectively throughout that GOR range, indeed has operated continuously throughout the rising GOR, from mid-May to mid-August 2017.
Modelled GVF (Gas Void Fraction) at pump intake has ranged from 55% when the pump was installed to 77% – 85% currently, based on daily average data. Intermittent fluctuations up to 95% may be occurring.
Detailed production data was supplied by the operator / asset owner of Case Study #4 well for the entire production period of the well. This has been analysed in detail to develop the graphs figure 1 & figure 2.
Detailed specification of the 2 x conventional ESPs has been obtained from the OEM’s field service team on site at the time. A full description regarding the commissioning difficulties and short run time of both early conventional ESPs has also been provided.
Daily monitoring of pump & well operation has been available since the V-Pump was installed May 15, 2017.