Synergy of Intelligent Wireline Formation Testing Platform Together With Drill Stem Testing to Unlock Hydrocarbon Potential in Asia Greenfield

Résumé fourni par la source

Reservoir testing is often needed to understand flow potential and to confirm hydrocarbon discoveries. In Southeast Asia, reservoirs are frequently laminated,thinly bedded, and compartmentalized. Testing every individual (main) zone with Drill Stem Test (DST) is not economical due to cost and rig time constraints. Different testing methods have been used such as Tubing Stem Testing (TST) and multi zone DST, with and without Production Logging Tool (PLT) for zonal contribution analysis. However, these methods still need to flow hydrocarbon to surface, require a large footprint,i.e. separator units at surface, and flaring hydrocarbon to atmosphere. Interval Pressure Transient Test (IPTT) and Deep Transient Testing (DTT) have been introduced as greener alternative wireline testing methods, where each zone can be isolated and tested individually without flaring. IPTT has been used for more than 20 years to derive zonal permeability. IPTT tests single hydraulically connected layers; obtained permeability often compares well to testing derived permeability. However, IPTT feasibility is limited in terms of permeability ranges, thickness, and reservoir fluid viscosity. With the introduction of DTT, the use of a circulating sub has enabled much larger volumes to be pumped with longer periods without jeopardizing well stability. With higher flowrates and improved gauge resolution, a much deeper radius of investigation can be achieved with this green testing technology, and higher permeability gas reservoir testing is now feasible. This paper will show examples where DST with either IPTT or DTT have been acquired on the same well. In each case, an integrated workflow for log-to-reservoir scale model is constructed from formation testing data and high-resolution logs, which is used to generate a zonal inflow performance relationship (IPR). In the first example, an IPTT was conducted after quality fluid samples were acquired which was followed by a commingle DST. The IPTT is used to derive individual layer permeability within the DST interval and to characterize zonal contributions. This is of critical importance for the production and reservoir recovery strategy in this multi-zone reservoir. In the second example, both DTT and DST were run in a high-permeability gas reservoir. Results are compared in terms of fluid sampling and pressure transient data. An integrated workflow was used to upscale the DTT calibrated model to the DST zones. In this example, even with a small DTT drawdown, the pressure transient from high-resolution gauges allowed for valid transient data. This paper shows a comparison of DTT to DST in a high-and low-permeability gas reservoir together with the discussion of test selection implications such as interpretation techniques together with lessons learned and best practices.

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