500 600 700 800
100 200 300 400
0 -20 15 10 5 0 -2 -5 -10 -15 Firing head -5 4 0 -3
Dogleg severity Orienting weight Swivel
OCD result 6 5 Plot area -15 -10 –+ 5° -5 0
Perforation-tunnel orientation, deg
5 10 –+ 5° 15 20
350°
Phasing histogram
10°
-1
151
101 Perforating string components
51
> Perforation orientation at Rimfaks. The OrientXact system OCD units recorded perforation orientation across four reservoir sections after the Rimfaks I-3H well was perforated for Statoil (bottom). Shot with 10° /350° phasing, all perforations were within 6° of target (blue). Dogleg severity (green) varies from zero to approximately 5° from horizontal and appears to have had no effect on perforation orientation. Vertical red lines indicate swivel locations between gun sections— orienting weights are shown as vertical brown lines. The green bars in the histogram (top) identify the number of perforation tunnels at each orientation angle relative to vertical.
1 Bullnose
To minimize sand production, engineers combined OrientXact and PowerJet Plus technologies to simultaneously perforate targets along the 3,400-ft [1,036-m] horizontal section. With a total of eight OCD units, the largest perforation orientation variance measured only 6° (above). The PowerJet Plus charges provided narrow, ultradeep penetration, optimizing perfo- ration-tunnel stability and maximizing communication with the reservoir past any for- mation damage in the near-wellbore area. By design, PowerJet Plus charge debris is retained in the gun. On the I-3H well, only 130 g [4.59 oz] of small metal pieces and fi lings were recovered. The use of steel-cased PowerJet Plus charges eliminated zinc by-product precipitation
and the associated near-wellbore formation dam- age seen on previous wells. Accurate oriented perforating combined with novel charge design produced deep, low-debris and precisely oriented perforations, eliminating the need for subse- quent workover and stimulation treatments. Sand production was limited and well perfor- mance improved.
New Paths for Oriented Perforating Operators have seen the value of oriented perfo- rating in initial completions and in remedial productivity enhancement. Cost-effi ciency gains, rig-time savings and production optimization are typical benefits of oriented perforating opera- tions. Coiled tubing conveyance, combined with
new orientation techniques, allows operators to accurately perforate under live-well conditions across tortuous and extended horizontal well- bores. When oriented perforating technology is combined with novel shaped-charge design, dynamic underbalanced techniques, real-time depth correlation capability, safety systems and OCD devices, operators optimize completions, costs and well productivity.
As the OrientXact system and related tech- nologies mature, their application to fracturing and screenless-completion operations may allow even more fl exibility in cost-effective production- enhancement operations through exacting perforation orientation.
— DW
Spring 2004
37
OCD results, deg/dogleg, deg/30 m [deg/98.4 ft]
Number of tunnels
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