Case Study of Integrated Solutions Used To Locate and Extract Bypassed Hydrocarbons in the Mature Reservoirs of the Algyö Field, Hungary

Abstract

Globally, the provable reserves of new discoveries have been reduced, makingthe technological challenges of EOR/IOR and increased recovery factors evenmore important. Many of these same technologies can be tested for new discoveryapplications through extensive evaluation in mature, established fields. This paper focuses on four primary areas:–Review the evolution of reservoir recovery technology in Algyö Field.–Outline the various IOR techniques and how they have enhancedproduction–Explain the science and methods of the innovative technologies that haveallowed us to push the envelope of reservoir understanding and recovery furtherout over time–Emphasize reservoir simulation enhancement and pre-drill well pathqualification through wellbore fluid saturation measurements extracted fromexisting wellbores Pursuant to the discussion of the four areas above, we will emphasize indetail:–Geological and petrophysical environment–Production history - Increased oil recovery methods and associated uplifts as: Utilizing horizontal wells, including planning, successes and challenges, direct application of carbon/oxygen ratio and pulsed neutron captures data toreservoir simulation enhancement and horizontal well planning in a fieldexploited mainly by water injection technology. Introduction Study Objectives for location bypassed hydrocarbons in AlgyöField C/O logging began in 2003. The main objective was to determine the currentwater saturations and gas contacts in the Csongrad-Del-1 and Szo-1 reservoirsin twelve ALGYO field wells. A second objective was to locate bypassedhydrocarbons to aid in the planning and selection of drilling targets forsubsequent horizontal well drilling programs. A third objective was to enhancereservoir description through updated lithology identification. Finally, afourth objective was to monitor changes in the gas column in one crestal wellthrough time-lapse logging. These objectives were to be met with all production hardware in place, andwith minimal disruption in hydrocarbon production from the intervals belowthese logging campaign's zones of interest. Geological Environment of Algyo Field Until now, 76 reservoirs were explored, both saturated and undersaturatedoil and gas reservoirs can be found among them. The reservoirs situated in1500–2600 mss zone were formed on the compactional anticlinal of N-NW, S-SEdirection, were deposited on the structural basement. (Fig.1.) For more than 30years, the hydrocarbon production has come from four main geological intervals:Paleozoic, fractured metamorphic basement; Lower-Pannonian age basalticconglomerates above the basement; Lower-Pannonian turbiditic sandstones andUpper-Pannonian deltaic sandstones. The Lower-Pannonian age basalticconglomerates means mainly the Deszk gas formation nowadays for water disposal.It originally contained 20% of the gas reserves. The Lower-Pannonian productivezone consists of turbiditic sandstones and marls with low porosity andpermeability. The Alsopannon-13 reservoir which is the most important targetzone for horizontal sections and Alsopannon-14 gas reservoir are in thiszone.