API COMMITTEE ON COOPERATIVE TESTING SGS STUDY FROM DATA

Transcription

1 API COMMITTEE ON COOPERATIVE TESTING SGS STUDY FROM DATA

2 OVERVIEW OF PRESENTATION This is a review of the data only No testing apparatus presented is portrayed as better than another The purpose of this exercise is to present data and not recommend equipment Three types of equipment are presented Ultrasonic Others Rotating

3 TESTING A test procedure was given for this SGS study Not all tests were performed the same way Sonic SGS 100F in 30 minutes in Atmos. Consistometer then transferred to preheated cup, then pressurized 2000 psi and held at 100F for duration of test Rotating SGS heated and pressurized to 100 F and 2000 psi in 30 minutes while stirring at 150 rpm, then converted to SGS stirring mode (0.2 /min)

4 Standardizing the Test The lack of pressure on the conditioning for the Sonic device may have had a bearing on the longer times and variations. A possible better evaluation of the test data and equipment would be to pick a schedule such as recommended in API RP 10B 6. This would increase the temperature and pressure while stirring at 150 rpm in the Rotating SGS apparatus to bottom hole conditions and holding for 10 minutes, then changing to the SGS stirring mode (0.2 /min). I would also suggest increasing the temperature to the BHST over a 4 hour period. For the Sonic SGS Apparatus, the conditioning would be to the same temperature and pressure in a HPHT consistometer and then transferred to the preheated Sonic SGS Apparatus. After the transfer, the pressure would be held constant and the temperature heated to BHST as for the Rotating SGS Device and held for the duration of the test. This would more closely simulate the suggested method for testing from API RP 10B 6. A possible schedule could be either Schedule 4 from API Spec 10A with a BHCT of 113 F and BHST of 170 F or Schedule 5 with a BHCT of 125 F and BHST of 200 F. This would prevent having to cool the HPHT consistometer for the transfer to the Sonic SGS Apparatus and be an actual API recommended method of performing the static gel strength test.

5 Figure 1 Shows the initial SGS indication and there was variability in all tests and a few more high initial SGS values for the rotating SGS unit.

6 Figure 2 Figure 2 shows the time to 100 lb/100 sq ft.. There is a lot of variation between the various instruments and also between the same type of instrument.

7 Figure 3

8 DG1 FIGURE 3 Figure 3 above contains the test data for the time to 500 lb/100 sq ft. This includes the time to 100 lb/100 sq ft from Figure 1. So this period of time is the total time the fluid should transmit hydrostatic pressure until it should not transmit hydrostatic pressure, or very minimal hydrostatic pressure to the formation. In this graph the time to 100 lb/100 sq ft (which is included in the time to 500 lb/100 sq ft) is influencing the data and is causing high variability for all systems even though the transition time for the rotating SGS apparatus is much shorter than for the others

9 Slide 8 DG1 D Dennis Gray, 1/15/2014

10 Figure 4

11 FIGURE 4 Figure 4 above shows the Transition Time for the various instruments. The Sonic system had longer Transition Time values and varied considerably from lab to lab. Since there were only two (3) labs that tested using the other SGS device which included 2 rotating type and one Delo (unknown to me), there is not enough data to make any kind of comparison. The Rotating SGS device (from the same manufacturer) had Transition Time data much shorter than the others in general and the Transition Times for this instrument had much less variation between the longest and shortest test.

12 Figure 5

13 FIGURE 5 Figure 5 shows comparisons of the time to 100 lb/100 sq ft as well as the Transition Time on the same chart. As for Figure 1, it does not indicate one instrument has a closer grouping of data for the time to 100 lb/100 sq ft for any of the instruments. But it does indicate a closer grouping of the transition time for the Rotating SGS instrument. The averages for all the tests performed as well as for the individual instruments are shown. The first two instruments contained long times between the minimum and maximum times and the times varied considerably from one lab to the other for both the time to 100 lb/100 sq ft and the Transition Time.