Recently, a different operator expanded on
the application of ICD completions, not to coun- ter the effects of uneven inflow profiles but to counter uneven pressure profiles. In one horizon- tal well extending more than 5,200 ft [1,600 m] through a high-permeability reservoir in a large Middle East field, the pressure differential between heel and toe was 200 psi [1.4 MPa] with the higher pressure at the heel.8 An initial production log confirmed what was
expected given the pressure profile: A downward crossflow of fluids from heel to toe was detected during a shut-in logging pass. In addition, produc- tion logging measurements acquired while the well was flowing showed water moving downward from the heel and oil flowing to the surface. Logs also indicated production was coming from only the first 10% of the lateral.9 Based on the results of static modeling, the
operator recompleted the well with 22 ResFlow ICDs and, to segment the well, seven swellable packers on the production string. Logs acquired after recompletion indicated that crossflow had been eliminated and production was coming from the entire lateral. Water cut was reduced from 30% to less than 10%, and the actual inflow profile matched that predicted by the static ICD model (above right).10
A Clean Start Predictably, it has been observed that the differ- ence in pressure drops between the heel and toe caused by friction losses in an openhole horizon- tal well increases with wellbore length. This disparity can lead to the filtercake being prefer- entially lifted from the wellbore wall at the heel and to poor inflow performance caused by corre- spondingly higher skin at the toe. Studies have shown that in relatively high- permeability environments, the best cleanup results—removal of filtercake after drilling or completion—are obtained through proper chem- ical treatment and extended flowback with high rates.11
In 2006 Saudi Aramco completed two test
wells equipped with ICD systems, one in a sand- stone formation and the other in carbonate rock. In the sandstone there were concerns over water and gas coning through high-permeability streaks, and the operator sought to decrease the impact of the heel-toe effect to improve cleanup and sweep efficiency. The 8½-in. openhole com- pletion included 5½-in. screens with ResFlow ICD nozzles on every joint of tubing. For compart- mentalization and better inflow control, small, swellable elastomer packers were placed on every second joint. The horizontal section was 2,540 ft [775 m] long.
Winter 2009/2010 Simulated flow profile ICD completion actual flow profile
Heel 1 ICD ICD 1 ICD 2 ICDs Swellable packer
> Inflow profile from production log measurements. After installation of ICDs and swellable packers, production logging tools were run to acquire an inflow profile along the length of the well at low, medium and high flow rates. The inflow profile shown was obtained with the well flowing at the medium rate. Crossflow evident in earlier logs has been eliminated and flow contribution is evident from the entire lateral. The actual inflow profile (green) was very close to the simulated one (red). (Adapted from Krinis et al, reference 8.)
The well was produced at 6,000 to 7,000 bbl/d
[953 to 1,113 m3/d] for 4 months. A production log was then acquired. The log data, as well as the inability to get the tool within 650 ft [198 m] of TD because of solids-laden mud filling the toe of the wellbore, indicated the well had not cleaned up despite the prolonged flow period. The flow rate was then increased to 9,000 to 10,000 bbl/d [1,430 to 1,590 m3/d] for 4 h and the
1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000
0 9,000 9,300 9,600
9,900 10,200 10,500 10,800 11,100 11,400 Measured depth, ft
11,700
> Cleanup through higher rates. After the logging tool failed to reach TD and log data indicated no production contribution from the toe after an initial flow period of 4 months (red), the rate was increased to about 9,000 to 10,000 bbl/d for 4 h and the production log was rerun. Log data yielded an improved flow profile, and the tool was able to travel an additional 350 ft (gray). Four hours later, the logging tool was run to within 50 ft of TD (green). The rate was returned to about 6,000 to 7,000 bbl/d, and log data demonstrated a permanent change had been made to the inflow profile (blue). (Adapted from Sunbul et al, reference 12.)
8. Krinis D, Hembling D, Al-Dawood N, Al-Qatari S, Simonian S and Salerno G: “Optimizing Horizontal Well Performance in Nonuniform Pressure Environments Using Passive Inflow Control Devices,” paper OTC 20129, presented at the Offshore Technology Conference, Houston, May 4–7, 2009.
9. Krinis et al, reference 8. 10. Krinis et al, reference 8.
11. Shahri AM, Kilany K, Hembling D, Lauritzen JE, Gottumukkala V, Ogunyemi O and Becerra Moreno O: “Best Cleanup Practices for an Offshore Sandstone Reservoir with ICD Completions in Horizontal Wells,” paper SPE 120651, presented at the SPE Middle East Oil and Gas Show and Conference, Bahrain, March 15–18, 2009.
well was logged again. The new data indicated an improved flow profile and the tool was able to travel an additional 350 ft [106 m]. Four hours later, the logging tool was run again, this time to within 50 ft [15 m] of TD (below). The rate was reduced to the original 6,000 to 7,000 bbl/d and data from the final logging run indicated a permanent change had been made to the inflow profile.
Initial log at 6,000 bbl/d Initial log at 9,000 bbl/d Repeat log at 9,000 bbl/d Repeat log at 6,000 bbl/d
Measured depth 2 ICDs 3 ICDs 3 ICDs 4 ICDs 5 ICDs
Toe
OSWIN09/10—Rick, story #2—Figure 09
35
Production, bbl/d
Production rate, bbl/d
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64