., . (1999) Cotton Valley Fracture Imaging Project Phase III. Technical Report. Gas Research Institute.
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Abstract
This report contains the results of Pinnacle Technologies’ fracture engineering, well testing anddownhole tiltmeter fracture mapping analysis of four hydraulic “waterfrac” treatments in theCGU 22-9 (Cotton Valley formation), located in Carthage, East Texas. The main purpose of thisJIP Phase III (Joint Industry Project) was to characterize the geometry and growth of waterfracs(gel-less and low proppant concentration treatments) in the Cotton Valley formation.Microseismic fracture mapping of fractures in an offset well (CGU 21-10 JIP Phase I) initiallyindicated the possibility of asymmetric fracture growth, although more extensive processing laterrevealed a more symmetric shape. For this reason we performed downhole tiltmeter fracturemapping on the two upper treatment stages of the CGU 22-9 to determine if fractures growasymmetrically or not. In order to accurately measure fracture length in both wings and thusaddress the question of lateral growth asymmetry, two tiltmeter arrays, consisting of ninetiltmeters each, were deployed in two offset producer wells (CGU 22-4 located 1378 ft. to theWest and CGU 20-6 located 1341 ft. to the East of the treatment well). The location of theseobservation wells (Figure 1) are roughly in line with the anticipated fracture azimuth of N 70q E,previously obtained from microseismic imaging. Ideal placement of downhole tiltmeter arraysrequire they be lowered to a position where the tiltmeter in the middle of the array is at the samedepth as the anticipated center of the fracture (often taken to be the middle of the perforatedinterval). This position maximizes the tiltmeter response to fracture-induced tilt changes thusincreasing the accuracy in the measurement of fracture dimensions. Unfortunately, due topermanent packers at about 8,300 ft depth in both observation wells, we had to position thetiltmeter arrays significantly above the treatment intervals ranging from 8,645’ to 9,614’. Thisprohibited mapping of Stages 1 and 2, but also rendered Stage 3 unmappable.Stress testing (to determine shale and limestone stresses) was performed in four zones and welltesting in two zones. The results of these tests were used to fine tune fracture modeling resultsand compare them with the microseismic imaging results in the CGU 21-10 and tiltmetermapping results in the CGU 22-9.
| Item Type: | Reports (Technical Report) |
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| Subjects: | Methodology > Other-additional study Region > USA > Texas > Cotton Valley Inducing technology > Unconventional hydrocarbon extraction |
| Project: | SERA > COTTON VALLEY: uconventional hydrocarbon extraction |