Novel Integrated Behind Casing Opportunity Maturation Workflow

Abstract

To appraise remaining behind casing opportunities in brown field after years of production, and depletion of main perforation intervals. Offshore environment is challenging and ensuring the presence of hydrocarbon requires significant investment, which is not always viable due to the economical additional reservoirs margin. A novel multidisciplinary workflow is developed to add assurance in apprising the remaining opportunities within the Idle wells prior to progress towards plug and abandonment. Limited data availability and economics allowed the development of a workflow to reduce uncertainty and ensure the presence of hydrocarbon when no cased hole saturation logging is justifiable. The workflow starts by relooking into the open hole logs to identify additional or marginal reservoirs. A complication index is assigned to each which refers to the easiness of the planned additional perf and the success ratio based on open hole data. A complete study to nearby wells production and the water oil contact movement is carried out based on the assigned complexity index. Opportunities were then ranked against the economics of additional perforation, cement bond logs were used to identify behind casing channeling especially when a gas or water contact is interpreted. The workflow which integrates the reservoir static and dynamic sand aligns petrophysics, dynamic model, history match and contact movement is developed to mitigate any behind casing opportunity consequent to no cased hole logging possibility, and to minimize the risk of not encountering hydrocarbon due to the long production. Any misleading allocation, potential risk (sand, wax, gravel pack, other completion accessories), predict future production based on location of new perf, plan for simulation or production enhancement job, remedial job, identify potential fault (unseen) at limited pressure data block, The workflow is proven to be successful to derisk the presence of hydrocarbon and to identify the most promising hydrocarbon bearing formations, with positive results as perforations are carried out where hydrocarbon are flew. This novel, comprehensive and integrated workflow generated a reliable tool to identify remaining potential trapped behind casing and possible risks of fluid type, current contact, impurities and well completion. The workflow is developed to generalizes the methodology to assess remained hydrocarbon within idle or high water cut wells, with risk reduced because each discipline contributed to the assessment with the potential risk associated with their discipline. Proper plan is together, capturing all possible risks and ensuring capturing the remained hydrocarbon.