Increasing the informativity of capillarimeter investigations using semipermeable membrane method

UDK: 622.276.031.011.43
DOI: 10.24887/0028-2448-2018-7-78-81
Key words: capillary pressure, residual saturation, shear pressure, investigation methodology, low-permeability reservoirs
Authors: S.P. Mikhaylov (RN-UfaNIPIneft LLC, RF, Ufa), M.V. Mavletov (RN-UfaNIPIneft LLC, RF, Ufa)

The exact determination of water saturation is one of the most important and complex questions for estimation of hydrocarbon reserves. The laboratory test quality influences on the successful solution of this problem. However, at the present there is no single standard for the case of low-permeability reservoirs. The analysis has revealed that the OST 39-204-86 (industrial standard) provisions that were developed in 1986 for good reservoir properties and low clay content in the pore space, not for low-permeability reservoirs. In this paper the experimental protocol for core test using semipermeable membrane is considered. The advantages and disadvantages of this method are pointed out. Recommendations for increasing the informativity were developed. It includes: the sampling from different lithological groups, the scheme for capillary pressure changing for laboratory test in the case of low-permeability rocks (at least 11 steps with a maximum pressure value not less than 1 MPa), an algorithm for the transition between pressure steps (at least 72 hours needed after filtration ceased), individual capillarimeter test necessity (at the atmospheric and reservoir conditions). In addition, the criterion for the capillary pressure curves quality was developed. The most common reasons of poor quality results are considered. The additional useful information from experimental investigations (pore size distribution, wettability parameter, etc.) is discussed.

References

1. Plyusnin G.V., Khizhnyak G.P., Fizika plasta (Reservoir physics), Perm': Publ. of PSTU, 2013, 219 p.

2. Ratnikov I.B., Shul'ga R.S., Romanov E.A., Interpretation of research data curves capillary pressure (In Russ.) Gornye nauki i tekhnologii, 2016, no. 4, pp. 24–39.

3. Belov Yu.Ya., Usovershenstvovanie kapillyarimetricheskogo metoda issledovaniya porod-kollektorov dlya opredeleniya ryada parametrov podscheta zapasov nefti i gaza (Improvement of the capillarimetric method for studying reservoir rocks to determine the parameters for calculating oil and gas reserves): thesis of candidate of geological and mineralogical science, Moscow, 1980.

4. Hammervold W.L., Skjæveland S.M., Improvement of diaphragm method for drainage capillary pressure measurement with micro pore membrane, Proceedings of EUROCAS meeting, September 1992, pp. 8–10.

5. Yur'ev A.V., Chizhov D.B., Recommendations on the residual water saturation modeling in laboratory conditions upon whole core samples (In Russ.), Vestnik Severnogo (Arkticheskogo) federal'nogo universiteta. Seriya “Estestvennye nauki”, 2015, no. 1, pp. 50–55.



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