Field Diagnosis and Measurement of Formation Damage
Field tests are regularly carried out for formation damage monitoring. Using appropriate precursors or signatures for detection of the imminent formation damage problems and their impact on oil production rates are important for two reasons, as stated by Hayatdavoudi (1999):
1. It would help us understand the reasons for a premature drop in oil production or formation damage.
2. It would give us adequate time to take the necessary, preventive remedial action(s) prior to the onset of a serious damage or an unusual drop in oil and gas production.
In this chapter, the loss of productivity or injectivity of wells by formation damage is expressed by alternative measures, and the various tests available for measurement and diagnosis of formation damage problems in the field are described.
Diagnosis and Evaluation of Formation Damage in the Field
As stated by Yeager et al. (1997), "No individual test or tool can provide the only information needed for damage mechanism identification and evaluation, and a historical perspective rather than an isolated perspective will result in a more complete diagnosis of the presence and type of damage." Therefore, Yeager et al. (1997) further elaborate that "Damage mechanism identification requires a systematic approach to research, planning, and evaluation of all available information." For the most part, the diagnosis and measurement of formation damage in the field rely on well testing, well logging, history matching, and produced fluid analysis. The determination of the mechanisms responsible for loss of flow efficiency (productivity or injectivity) requires a number of studies. Yeager et al. (1997) recommend a three-stage approach consisting of:
1. Quantifying the degree of existing damage
2. Diagnosing the existing downhole damage mechanisms
3. Performing laboratory studies to increase knowledge about specific mechanisms
For this purpose, formation damage studies begin with the classification of the reservoir formation and review of the operational and engineering processes. The flow chart given by Yeager et al. (1997) in Figure 22-1 describes the information required on various aspects. The methodology for determination of the mechanisms responsible for flow efficiency is described in the flow chart given in Figure 22-2 by Yeager et al. (1997). Although, the Yeager et al. (1997) approach is intended for identification of damage in gas-storage wells, its applicability is extended here for general applications. As stated by Yeager et al. (1997), the typical downhole diagnostic tests that can be conducted in the field include:
1. Well-test analysis to determine quantitatively if damage exists
2. Downhole video to observe the wellbore and formation areas
3. Physical sampling in the form of downhole liquids and solids
4. In the openhole completions, rotary sidewall core samples of the wellbore face as a "biopsy" of the storage formation
Yeager et al. (1997) recommend a downhole video run prior to the other downhole diagnostic tests and sampling for assessment of the presence, nature, and morphology of deposits on the wellbore surface and
perforations. Figure 22-3 by Yeager et al. (1997) shows a schematic of a typical high-resolution video camera and a still image, indicating significant
wellbore scaling, obtained using this camera. The video observations also provide valuable information necessary for determination of the flow distribution that can be used to improve the accuracy of the welltest interpretation and identification of the formation damage mechanisms (Yeager et al., 1997).
Pressure transient tests yield information on the permeability and formation thickness product, (Kh), and skin factor, s. As pointed out by Yeager et al. (1997), pressure transient tests only provide information at a specific time, when the tests are conducted. Therefore, formation damage can be more effectively evaluated by conducting a series of tests over a length of time and also the true skin should be determined after corrections for other effects, such as non-Darcy or inertial effects (Yeager et al., 1997).
In openhole completed wells, core samples can be taken from the wells using a rotary sidewall coring tool (Yeager et al., 1997). The material on the face of the extracted cores should be carefully preserved during the transportation of the core for later analytical studies (Yeager et al., 1997).
References
Akaike, H., "Mental Preparation for Time Series Analysis," The Practice of Time Series Analysis, Akaike, H., & Kitagawa, G. (eds.), Springer-Verlag New York, Inc., New York, New York, 1999, Chapter 23, pp. 367-371.
Amaefule, J. O., Kersey, D. G., Norman, D. L., & Shannon, P. M., "Advances in Formation Damage Assessment and Control Strategies," CIM Paper No. 88-39-65, Proceedings of the 39th Annual Technical Meeting of Petroleum Society of CIM and Canadian Gas Processors Association, June 12-16, 1988, Calgary, Alberta, 16 p.
Craft, B. C., & Hawkins, M. F., Applied Petroleum Reservoir Engineering, Prentice Hall, 1959.
Dias-Couto, L. E., & Golan, M., "General Inflow Performance Relationship for Solution-Gas Reservoir Wells," /. of Petroleum Technology, February 1982, pp. 285-288.
Hayatdavoudi, A., "Effect of Water-Soluble Gases on Production Decline, Production Stimulation, and Production Management, SPE 50781 paper, presented at the 1999 SPE International Symposium on Oilfield Chemistry, Houston, Texas, February 16-19, 1999.
Lee, J., & Kasap, E., "Fluid Sampling from Damaged Formations," SPE 39817 paper, Proceedings of the 1998 SPE Permian Basin Oil and Gas Recovery Conference, March 25-27, 1998, Midland, Texas, pp. 565-570.
Lekia, S., & Evans, R. D., "Generalized Inflow Performance Relationship for Stimulated Wells," Journal of Canadian Petroleum Technology, Vol. 29, No. 6, November-December 1990, pp. 71-75.
Leontaritis, K. J., "Asphaltene Near-Wellbore Formation Damage Modeling," SPE 39446 paper, Proceedings of the 1998 SPE Formation Damage Control Conference, February 18-19, 1998, Lafayette, Louisiana, pp. 277-288.
Li, Y-H., Fambrough, J. D., & Montgomery, C. T., "Mathematical Modeling of Secondary Precipitation from Sandstone Acidizing," SPE Journal, December 1998, pp. 393-401.
Mukherjee, H., & Economides, M. J., "A Parametric Comparison of Horizontal and Vertical Well Performance," SPE Formation Evaluation, June 1991, pp. 209-216.
Muskat, M., The Flow of Homogeneous Fluids Through Porous Media, McGraw-Hill Book Co., New York, New York, 1937.
Muskat, M., Physical Principles of Oil Production, McGraw-Hill, Inc., New York, 1949.
Ohen, H. A., & Civan, F, "Simulation of Formation Damage in Petroleum Reservoirs," SPE 19420 paper, Proceedings of the 1990 SPE Symposium on Formation Damage Control, Lafayette, Louisiana, February 22-23, 1990, pp. 185-200.
Ohen, H. A., & Civan, F., "Predicting Skin Effects Due to Formation Damage by Fines Migration," SPE 21675 paper, Proceedings of the 1991 SPE Production Operations Symposium, Oklahoma City, Oklahoma, April 7-9, 1991, pp. 399-410.
Ohen, H. A., & Civan, F, "Simulation of Formation Damage in Petroleum reservoirs," SPE Advanced Technology Series, Vol. 1, No. 1, April 1993, pp. 27-35.
Olarewaju, J. S., "A Mathematical Model of Permeability Alteration Around Wells," Intl. J. for Numerical and Analytical Methods in Geomechanics, Vol. 14, 1990, pp. 191-207.
Piot, B. M., & Lietard, O. M., "Nature of Formation Damage in Reservoir Stimulation, in Economides," M. J. & K. S. Nolte (eds.), Reservoir Stimulation, Schlumberger Education Services, Houston, Texas, 1987.
Vogel, J. V, "Inflow Performance Relationships for Solution-Gas Drive Wells," J. of Petroleum Technology, January 1968, pp. 83-92.
Yan, J., Jiang, G., & Wu, X., "Evaluating of Formation Damage Caused by Drilling and Completion Fluids in Horizontal Wells," Journal of Canadian Petroleum Technology, Vol. 36, No. 5, 1997, pp. 36-42.
Yeager, V. J., Blauch, M. E., Behenna, F. R., & Foh, S. E., "Damage Mechanisms in Gas-Storage Wells," SPE 38863 paper, Proceedings of the 1997 SPE Annual Technical Conference and Exhibition, October 5-8, 1997, San Antonio, Texas, pp. 477-486.
Zhu, D., Hill, A. D., & Morgenthaler, L. N., "Assessment of Matrix Acidizing Treatment Responses in Gulf of Mexico Wells," Proceedings of the 1999 SPE Mid-Continent Operations Symposium held in Oklahoma City, Oklahoma, USA, March 28-31, 1999.
