Field and Laboratory Experience in Closed Fracture Acidizing the Lisburne Field, Prudhoe Bay, Alaska

Abstract

Field and Laboratory Experience in Closed Fracture Acidizing the Lisburne Field, Prudhoe Bay, Alaska K.M. Bartko; K.M. Bartko ARCO E and P Technology Search for other works by this author on: This Site Google Scholar M.W. Conway; M.W. Conway STIM-LAB Inc. Search for other works by this author on: This Site Google Scholar T.E. Krawietz; T.E. Krawietz ARCO Alaska Inc. Search for other works by this author on: This Site Google Scholar R.B. Marquez; R.B. Marquez ARCO Alaska Inc. Search for other works by this author on: This Site Google Scholar R.G.M. Oba R.G.M. Oba ARCO Alaska Inc. Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Washington, D.C., October 1992. Paper Number: SPE-24855-MS https://doi.org/10.2118/24855-MS Published: October 04 1992 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Bartko, K.M., Conway, M.W., Krawietz, T.E., Marquez, R.B., and R.G.M. Oba. "Field and Laboratory Experience in Closed Fracture Acidizing the Lisburne Field, Prudhoe Bay, Alaska." Paper presented at the SPE Annual Technical Conference and Exhibition, Washington, D.C., October 1992. doi: https://doi.org/10.2118/24855-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search SPE MembersAbstractThis paper describes the laboratory and field work performed to understand and improve the stimulation of the fractured carbonate formation producing in the Lisburne Field, Prudhoe Bay, Alaska. Within the producing formations, the lower Wahoo intervals are low permeability, fractured dolomitic zones that produce poorly when compared to the higher permeability upper intervals. Past attempts to stimulate these intervals have included propped fracture techniques and standard acid fracture techniques. A laboratory study evaluated the effects that various acid systems have on Wahoo rock properties, the degree of permeability enhancement, and stability of acid fracture conductivity. Various acid fracturing techniques were also investigated to determine which technique and acid system created long-term fracture conductivity. The laboratory study indicated the optimal treatment would be obtained by using emulsified acid in a fracture acidizing treatment followed by a closed fracture acidizing stage using emulsified acid. The unique combination of this particular acidizing technique and acid system has increased productivity in the Lisburne Field.Complete documentation of the field work optimization program is included in this paper. Pressure buildup (PBU) analysis has indicated fracture half lengths are from 25–100 feet long and production spinner surveys have determined that lower intervals are contributing to production. To date, over 40 new and old wells have been stimulated using emulsified acid with the closed fracture acidizing technique. Significant increases in production and reserves are currently being seen from this program.IntroductionInitial well stimulations in the Lisburne field consisted of 1/2 bbl/foot, approximately 100 bbls of 15% hydrochloric acid (HCl) pumped at matrix rates. Because of high perforation density, diversion was difficult with ball sealers or particulates. Production responses after these treatments were good with initial rate increases of 2,500–3,000 bopd, but rates declined rapidly during the first month of production. Production surveys indicated that the majority of production was coming from the top 10–20 feet, identified as a subunconformity alteration zone, or 'SAZ'. This interval is a highly permeable zone that is believed to be locally interconnected with the rest of the reservoir through faults and fractures.As development continued, less prolific wells were drilled as a result of poorer quality reservoir rock and because of 'SAZ' depletion. This situation required the development of a new stimulation technique to enhance production from the lower permeability intervals.Some early attempts to increase the productivity of these lower zones were acid fracturing with alternating stages of gelled water and 28% HCl and propped hydraulic fracturing. The initial acidfracs resulted in high initial rates but production rates declined rapidly to pre-stimulation rates. Simple acid fracturing created etched fractures that were too short. Deeper acid penetration was required to sustain long term productivity. Propped hydraulic fracturing limitations included conditions such as, low pump rates through 2–7/8 inch production tubing, high shot density in all intervals, and large gross thicknesses.P. 923^ Keywords: stimulation, pump rate, society of petroleum engineers, limestone, spe 24855, wormhole, closed fracture, upstream oil & gas, conductivity, nitrogen Subjects: Hydraulic Fracturing This content is only available via PDF. 1992. Society of Petroleum Engineers You can access this article if you purchase or spend a download.