Rapid Pressure Support for Champion SE Reservoirs by Multilayer Fractured Water Injection

Abstract

Summary The Champion field is a large oil field offshore Negara Brunei Darussalam. This paper discusses the (for us) novel application of water injection-induced multilayer fractured injection into three shallow reservoirs in the Champion Southeast (CPSE) field. Fractured water injection means that the bottomhole injection pressure is allowed to exceed the formation's fracture pressure. Thereby an unpropped fracture is created, which propagates depending on the injection water's leakoff rate into the formation. The project is part of a larger secondary recovery implementation scheme and future efforts to increase economic oil production and ultimate recovery in the whole Champion field. The main boundary condition for the rapid water injection project is the use of existing infrastructure with the exception of three new water pipelines and nine new wells. This paper describes the following:Reservoir setting and production history.Water injection philosophy.Design considerations for fractured water injection including:○Pressure requirement to design for fractured water injection.○Simulation of fracture growth and containment and resulting conclusions.Design considerations for the multilayer fractured water injector wells including:○Selected drilling aspects (well trajectory, drill-in fluid, formation evaluation, casing scheme).○Completion design considerations (cleanout, perforating, sand control, selectivity, "smartness", other).○Material selection. One of the main conclusions is that fracture growth and containment is not a major issue in soft, high-permeable formations. The main challenge is in drilling the—in some cases—demanding well trajectories and running the "smart" completions in these wells with small tolerances. Introduction The Champion Southeast (CPSE) field is part of the larger Champion field, which is the largest known offshore oil accumulation in Negara Brunei Darussalam, a small, oil-rich state on the north coast of the island of Borneo (Fig. 1). The CPSE field is located in 10 to 45 m water depth at a distance of approximately 40 km north of Bandar Seri Begawan, the capital of Negara Brunei Darussalam. This paper focuses on the rapid implementation of a pressure maintenance scheme using multilayer fractured water injection and related design and completion considerations for the water-injection wells to arrest the faster-than-anticipated pressure depletion in these shallow reservoirs.

A method to calculate reasonable water injection rate for M oilfield

“…For the development of multilayer sandstone heterogeneous water drive reservoirs, because of the inhomogeneous advance of injected water in vertical and horizontal directions, dominant channels of water flow in reservoir are formed (Li 2003;Wagn et al 2016;Sommerauer and Zerbst 2007). Therefore, there are a series of problems in extra high water cut stage including sharp production decline and rapid water cut rising (Hou 2014;Chen 1986;Rehman et al 2015).…”