New Acid-Tunneling Insights from Full-Scale Water- and Acid-Jetting Tests
- S. Livescu (Baker Hughes, a GE Company) | D. McDuff (Chevron) | B. Comeaux (Chevron) | A. Singh (Chevron) | B. J. Lindsey (Baker Hughes, a GE Company)
- Document ID
- Society of Petroleum Engineers
- SPE Annual Technical Conference and Exhibition, 30 September - 2 October, Calgary, Alberta, Canada
- Publication Date
- Document Type
- Conference Paper
- 2019. Society of Petroleum Engineers
- Coiled Tubing, Acid Tunneling, Full-Scale Tests, Carbonate, Acid Jetting
- 3 in the last 30 days
- 199 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 28.00|
Acid-tunneling is an acid jetting method for stimulating carbonate reservoirs. Several case histories from around the world were presented in the past showing optimistic post-stimulation production increases in open-hole wells, comparing to conventional coiled tubing (CT) acid jetting, matrix acidizing, and acid fracturing. However, many questions about the actual tunnel creation and tunneling efficiency are still not answered. In this paper, the results of an innovative full-scale research program involving water and acid jetting are reported for the first time.
The tunnels are constructed through chemical reaction and mechanical erosion by pumping hydrochloric (HCl) acid through conventional CT and a bottom-hole assembly (BHA) with jetting nozzles and two pressure-activated bending joints that control the tunnel initiation directions. If the jetting speed is too high and the acid is not consumed in front of the BHA during the main tunneling process, then unspent acid flows toward the back of the BHA and creates main wellbore and tunnel enlargement with potential wormholes as fluid leaks off, lowering the tunneling length efficiency.
Full-scale water and acid jetting tests were performed on Indiana limestone cores with 2-4 mD permeability and 12-14% porosity. Many field-realistic combinations of nozzle sizes, jetting speeds, and back pressures were included in the testing program. The cores were 3.75-in. in diameter by 6-in. in length for the water tests, and 12-in. in diameter by 18-in. in length for the tests with 15-wt% HCl acid. The jetting BHA was moved as the tunnels were constructed, at constant force on the nozzle mole, to minimize the nozzle stand-off distance. Six acid tests were performed at the ambient temperature of 46F and two at 97F. The results from the acid tests show that the acid tunneling efficiency can be optimized by reducing the nozzle size and pump rate. The results from the water and acid tests with exactly the same parameters to match the actual CT operations in the field show that the tunnels are constructed mostly by chemical reaction and not by mechanical erosion. The acid tunneling efficiencies obtained from the full-scale acid tests are superior to the average tunneling efficiency of more than 500 actual tunnels constructed during more than 100 acid tunneling operations performed to date worldwide.
The paper describes the full-scale water and acid jetting tests on Indiana limestone cores. The major novelty of this test program consists of performing all measurements with back pressure, unlike all previous water and acid jetting studies reported in literature, to more accurately mimic the downhole well conditions. The novel understanding of the combined effect of the nozzle size, pump rate, and back pressure significantly improves the actual acid-tunneling efficiency.
|File Size||1 MB||Number of Pages||15|
Beckham, R.E., Shuchart, C.E., and Buechler, S.R. 2015. Impact of Acid Jetting on Carbonate Stimulation. Presented at the International Petroleum Technology Conference, Doha, Qatar, 6-9 December. IPTC-18360-MS. https://doi.org/10.2523/IPTC-18360-MS.
Blanco, D., Sach, M., and Livescu, S. 2017. 3 ½-in. Coiled Tubing Telemetry System Saves Time and Improves Operational Efficiency during a Multi-Well Campaign in Norway. Presented at the SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, Houston, Texas, USA, 21-22 March. SPE-184754-MS. http://dx.doi.org/10.2118/184754-MS.
Diaz, J.D., Espina, V., Guerrero, M.. 2007. Successful Implementation of Coiled-Tubing Acid Tunneling Gives Operator a Viable Alternative to Conventional Stimulation Techniques in Carbonate Reservoirs. Presented at the SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, The Woodlands, Texas, USA, 20-21 March. SPE-107084-MS. https://doi.org/10.2118/107084-MS.
Guimaraes, Z., Duque, L.H., Almeida, V.. 2011. Construction Project for the First Dendritic Well Offshore in Brazil. Presented at the Brasil Offshore, Macaé, Brazil, 14-17 June. SPE-143081-MS. https://doi.org/10.2118/143081-MS.
Livescu, S., Blanco, D.A., Kubicki, K.. 2015. Novel 2 ?-in. Real-Time Downhole Data Monitoring System for Coiled Tubing Operations. Presented at the SPE Annual Technical Conference and Exhibition, Houston, Texas, USA, 28-30 September. SPE-174850-MS. https://doi.org/10.2118/174850-MS.
Livescu, S., and Craig, S. 2017. A critical review of the coiled tubing friction-reducing technologies in extended-reach wells. Part 1: Lubricants. JPSE 157, 747-759. https://doi.org/10.1016/j.petrol.2017.07.072.
Livescu, S., and Craig, S. 2018. A critical review of the coiled tubing friction-reducing technologies in extended-reach wells. Part 2: Vibratory Tools and Tractors. JPSE 166, 44-54. https://doi.org/10.1016/j.petrol.2018.03.026.
Livescu, S., Watkins, T., and Najafov, J. 2018a. Ten Years of Continuous Technology Development and Field Application of a Coiled-Tubing Tube-Wire Telemetry System: Past, Present, and Future. SPE J. SPE-187374-PA. https://doi.org/10.2118/187374-PA.
Livescu, S., Vissotski, A., and Chaudhary, S. 2018b. Improved Acid Placement Modeling for Matrix Acidizing Optimization. Presented at the SPE Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 12-15 November. SPE-193119-MS. https://doi.org/10.2118/193119-MS.
Livescu, S., Craig, S., and Aitken, B. 2018c. Tunnel-Length Modeling for Coiled-Tubing-Acid-Tunneling Stimulation in Carbonate Reservoirs. SPE P&O. SPE-188294-PA. https://doi.org/10.2118/188294-PA.
Moss, P.J., Portman, L.N., Rae, P.J.. 2006. Nature Had It Right After All! Constructing a "Plant Root"-Like Drainage System with Multiple Branches and Uninhibited Communication With Pores and Natural Fractures. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 24-27 September. SPE-103333-MS. https://doi.org/10.2118/103333-MS.
Ndonhong, V., Belostrino, E., Zhu, D.. 2017. The Impact of Rock Properties on Acid Jetting in Carbonate Rocks: An Experimental Study. SPE P&O. SPE-180113-PA. https://doi.org/10.2118/180113-PA.
Perex, P.A., Diaz, J.D., Navarro, M.. 2008. Successful Offshore Application of Acid Tunneling Technology: Overcoming the Difficulties of High Depths, Temperatures, and Deviations. Presented at the SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, The Woodlands, Texas, USA, 1-2 April. SPE-113855-MS. https://doi.org/10.2118/113855-MS.
Portman, L.N., Rae, P.J., and Munir, A. 2002. Full-Scale Tests Prove it Practical to "Drill" Holes with Coiled Tubing Using Only Acid; No Motors, No Bits. Presented at the SPE/ICoTA Coiled Tubing Conference and Exhibition, Houston, Texas, USA, 9-10 April. SPE-74824-MS. https://doi.org/10.2118/74824-MS.
Rae, P.J., and Di Lullo, G. 2001. Chemically-Enhanced Drilling With Coiled Tubing in Carbonate Reservoirs. Presented at the SPE/ICoTA Coiled Tubing Roundtable, Houston, Texas, USA, 7-8 March. SPE-68439-MS. https://doi.org/10.2118/68439-MS.
Rae, P.J., Portman, L.N., and Di Lullo, G. 2007. The Dendritic Well - A Simple Process Creates An Ideal Reservoir Drainage System. Presented at the European Formation Damage Conference, Scheveningen, The Netherlands, 30 May-1 June. SPE-108023-MS. https://doi.org/10.2118/108023-MS.
Ridner, D., Frick, T., Zhu, D.. 2018. Influence of Transport Conditions on Optimal Injection Rate for Acid Jetting in Carbonate Reservoirs. Presented at the SPE International Conference and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 7-9 February. SPE-189546-MS. https://doi.org/10.2118/189546-MS.
Stanley, R., Portman, L.N., Diaz, J.D.. 2010. Global Application of Coiled-Tubing Acid Tunneling Yields Effective Carbonate Stimulation. Presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19-22 September. SPE-135604-MS. https://doi.org/10.2118/135604-MS.
Wehunt, C.D., Lattimer, S.K.K., and McDuff, D.R. 2018. Dendritic-Acidizing Update: The Light at the End of the Tunnel. SPE P&O. SPE-189945-MS. https://doi.org/10.2118/189945-MS.