Comparison of Water and Gas Tracers Field Breakthrough

We are developing new classes of barcoded advanced tracers, which, compared to present commercial offerings, can be optically detected in an automated fashion. The eventual goal for the advanced tracers is to deploy cost-effective, ubiquitous, long-term, and full-field tracer tests in supporting large-scale waterflooding optimization for improved oil recovery. In this paper, we compare model predictions to breakthrough data from two field tests of advanced tracers in a pilot during water alternating gas (WAG) cycles, where gas tracer tests have recently been performed as well. Two advanced tracer injections were performed at the test site. For the first injection, only a dipicolinic acid based advanced tracer (DPA) was injected. For the second injection, DPA and a phenanthroline- based advanced tracer, 4,7-bis(sulfonatophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BSPPDA), was injected in conjunction with a commercially available fluorobenzoic acid-based tracer (FBA) to benchmark their performance. Produced water samples were collected weekly for tracer analysis. Both newly developed 2D-high performance liquid chromatography/time-resolved fluorescence optical detection method (2D-HPLC/TRF) and liquid chromatography-mass spectrometry (LC-MS) were used to construct the breakthrough curves for the advanced tracers. In parallel, gas chromatography-mass spectrometry (GC-MS) was used to detect FBA tracer. Gas tracer tests have been performed on the same field. Since DPA, BSPPDA and FBA tracers were water tracers as designed, they were expected to appear in between gas tracer breakthroughs, and we observed exactly that for BSPPDA and FBA. Unexpectedly, the DPA predominantly appeared along with gas tracer breakthroughs, suggesting its favorable compatibility with the gas phase. We suspect the presence of some gas components rendered the medium more acidic, which likely protonates DPA molecules, thereby alters its hydrophilicity. A wealth of information could be gathered from the field tests. First, all tracers survived not only the harsh reservoir conditions but also the irregular WAG injections. Their successful detection from the producers suggested robustness of these materials for reservoir applications. Second, the breakthrough curves of the BSPPDA tracers using optical detection method were very similar to those of FBA tracers detected by GC-MS, substantiating the competency of our in-house materials and detection methods to the present commercial offerings. Finally, even though DPA has passed prior lab tests as a good water tracer, its high solubility to gas phase warrants further investigation. This paper summarizes key results from two field trials of the novel barcoded advanced tracers, of which both the tracer materials and detection methods are new to the industry. Importantly, the two co- injected advanced tracers showed opposite correlations to the gas tracers, highlighting the complex physicochemical interactions in reservoir conditions. Nevertheless, the information collected from the field trials is invaluable in enabling further design and utilization of the advanced tracers in fulfilling their wonderful promises.

World First Commercial Application of Permanent Interventionless Monitoring Using Intelligent Inflow Gas Tracer Technology

Over the past decade, commercially available inflow tracers have been increasingly used to permanently monitor lower completions without the need for intervention. They have been designed to release selectively to oil or water, typically for clean-up verification, inflow quantification and identifying the location of water breakthrough in oil reservoirs. Naturally, there has been an industry demand and requirement to develop inflow gas tracers to monitor gas reservoirs and identifying the location of gas breakthrough in oil reservoirs. In a green field development, it is important to obtain as much measurements as possible to understand completion efficiency and guide reservoir management decisions. This paper presents the first commercial installation of inflow gas tracer technology that has been deployed in a dry gas field by HESS Malaysia in open hole stand-alone screen completions. It discusses the original monitoring objectives of this application in a full field development and how they evolved due to the gas tracer capabilities and the need for early well and field information. This paper will also discuss the retrofit screen design that allowed the gas tracers embedded in a polymer matrix called gas systems (GS) to be installed inside premium mesh screens. At the wellsite, sampling campaign adjustments were executed depending on the flowing conditions during the clean-up, restarts to obtain relative flow contribution and inflow performance under multi-rate testing conditions. Using a structured approach, the inflow gas monitoring project included feasibility studies, well candidate selection, lessons learnt and developed best practices based on installations in six producing wells in the North Malay Basin (NMB).

METODE GAS TRACER UNTUK EVALUASI EFISIENSI VENTILASI TAMBANG BAWAH TANAH

Ventilasi tambang bawah tanah mempunyai peran penting untuk memastikan kecukupan suplai udara segar untuk pekerja tambang, mesin bakar internal, melarutkan gas dan partikulat, maupun menjaga suhu dan kelembaban udara. Design yang tidak benar dapat menyebabkan kebocoran dan resirkulasi udara, menurunkan efisiensi energi untuk sistem ventilasi secara total. Di lain hal, difusi turbulensi mengendalikan penyebaran gas dan partikulat.Makalah ini membahas penggunaan gas tracer untuk mengevaluasi efisiensi dari sistem ventilasi tambang. Dengan mencocokkan hasil pengukuran lapangan dengan simulasi numerik, kuantitas suplai udara yang terbuang disebabkan karena kebocoran dapat dievaluasi. Selain itu, laju pertukaran udara di front tambang juga di analisa berdasarkan data peluruhan gas. Sebagai hasil analisa, sekitar 53.5% udara bersih terbuang langsung melalui kipas utama. Sedangkan, laju pertukaran udara di salah satu front tambang, adalah sekitar 6.48 kali per jam.

Tracing circumnuclear dense gas in H2O maser galaxies

ABSTRACT A sample of 30 H$_{2}$O extra-galactic maser galaxies with their published HCN(J = 1 − 0) and HCO + (J = 1 − 0) observations has been compiled to investigate the dense gas correlation with H2O maser emission. Our sample number exceeds the size of the previous HCN samples studied so far by a factor of 3, and it is the first study on the possible relation with the dense gas tracer HCO + . We find a strong correlation between normalized H2O maser emission luminosity (LH2O/LCO) and normalized HCO + line luminosity (LHCO + /LCO). Moreover, a weak correlation has been found between LH2O/LCO and normalized HCN line luminosity (LHCN/LCO). The sample is also studied after excluding Luminous and ultraluminous infrared galaxy (U)LIRG sources, and the mentioned correlations are noticeably stronger. We show that ‘dense gas’ fractions as obtained from HCN and HCO + molecules tightly correlate with maser emission, especially for galaxies with normal IR luminosity (LIR < 1011 L⊙) and we show that HCO + is a better ‘dense gas’ tracer than HCN. Further systematic studies of these dense gas tracers with higher transition level lines are vital to probe megamaser physical conditions and to accurately determining how maser emission interrelates with the dense gas.