Reservoir Saturation Services
More hydrocarbons lie just behind the casing wall. The only question is how much and where.
A breakthrough in pulsed-neutron technology can be your second shot at booking more production. High-fidelity, behind-the-casing, reservoir-saturation data helps you detect bypassed oil and gas reserves in shut-in or underperforming wells.
Field Trials of a new Array Pulsed Neutron Formation Gas Measurement in Complex Completions
S. Bertoli, M. Borghi , and G. Galli, ENI E&P; A. Oprescu and S. Riley, Weatherford
In the gas fields of Adriatic offshore Italy, it has been common practice to complete wells using single- and dual string tubulars to manage production from different reservoirs. These completions complicate the measurement of formation gas saturation using pulsed neutron instruments by introducing significant and complex environmental effects. In a dual-string completion producing in a gas reservoir, for example, the annulus, logged tubing string, and adjacent tubing string may each contain either liquid or gas, yielding eight different possible completion environments. Recently a new generation of array pulsed neutron instrumentation having greater sensitivity to formation gas has been introduced into commercial service. This paper reports the first application of the array pulsed neutron tool and the associated interpretation technology in the single- and dual-string completions offshore Italy.
Surveillance of Complex Displacement Mechanisms in Mature Reservoirs to Maximize Recovery
Adrian Zett, Michael J. Webster, and Hilary Rose, BP; Stephen Riley, Darryl Eugene Trcka, and Nilesh Subhash Kadam, Weatherford
The Columbus basin offshore Trinidad is a mature hydrocarbon province. It contains multiple, stacked, discrete reservoirs which are supported and driven by complex displacement mechanisms. The reservoir surveillance challenges in the basin are compounded by the interaction of low salinity formation water, multiple fluid phases, thin beds, and completions that present difficult conditions for cased-hole reservoir monitoring instruments. Challenging current monitoring practices resulted in the implementation of new strategic measurements in the surveillance plan that delivered valuable insights and clarity to complex reservoir management problems. The results obtained using existing procedures and technologies highlighted their shortcomings and uncertainties. To address these issues emerging technologies were evaluated under these challenging conditions. The results obtained clearly prove that tangible benefits could be realized through the use of the new surveillance techniques. The benefits of applying new technology as part of an integrated surveillance strategy will be described in this paper. This new approach has helped reduce the uncertainty in both fluid contact movement and remaining hydrocarbon saturations. This has had a direct impact on reservoir simulation and the definition of future reservoir targets.
Application of New Generation Multi Detector Pulsed Neutron Technology In Petrophysical Surveillance
Adrian Zett, Michael Webster, David Spain, Donald Surles, and Chris Colbert, BP
The development of Multi Detector Pulsed Neutron (MDPN) technology marks a turning point in the way we address the current challenges within petrophysical surveillance. MDPN data is proving to be valuable in describing complex recovery mechanisms even when recorded in difficult logging environments and is capable of being deployed through a variety of conveyance methods. The measurements are available through logging while drilling (baseline only) and wireline instruments using three or more gamma detectors. This paper will focus on their application behind casing. There is a clear distinction in this paper between tools for data acquisition and generic work flows for data interpretation. There are various instruments available to acquire MDPN data, and it is important to understand what they measure and to what extent further processing is needed to generate usable results for the differing applications. A comparison of the raw data from all of the available instruments will be used to emphasize the benefit of the different MDPN measurements and their potential application to surveillance problems. We will present the operator’s perspective of the various applications of MDPN technology and the generic work flows that could be applied to all of the available tools.
Quantifying Gas Saturation with Pulsed Neutron Logging - An Innovative Approach
Mamdouh N Al-Nasser, Mark Ma, Nedhal Mushrafi, and Ahmed S. Al-Muthana, Saudi Aramco; Darryl Trcka, Steve Riley, Abel I. Geevarghese, and Aly Bassiouny, Weatherford
In reservoir surveillance, gas saturation is routinely monitored both in gas reservoirs for reservoir performance and in saturated oil reservoirs to prevent gas coning or to optimize infill drilling well placement. This paper presents a new pulsed neutron technology and method that enable the quantitative monitoring of the gas saturation variations to address these reservoir management issues. One of the key features of the newly designed pulsed neutron tool is the new type of Lanthanum Bromide (LaBr3) detectors. The extra-long spacing of the far detectors provides a larger volume of investigation that is more representative of the actual reservoir condition. The quantitative aspect of the measurement is achieved by using the ratios of the detector counts, so that the rock matrix effects are diminished, as opposed to the traditional sigma measurement, which can be influenced significantly by the rock matrix properties. This new tool and data interpretation methodology have been tested in both clastic and carbonate reservoirs with encouraging results. This paper presents an overview of the technology and some field application examples.
Weatherford pulsed neutron reservoir saturation services provide actionable bypassed-reserve data through first-of-its-kind hardware, advanced petrophysical workflows, and a wide range of transparent answer products.
Our technologies deliver behind-the-casing logs that identify the type, location, and amount of hydrocarbons. These products provide high-fidelity data for any cased-hole completion program and can also provide an alternative to traditional openhole wireline logs in new wells.
The Raptor reservoir saturation system includes the only five-detector-array pulsed neutron tool in the world.
With 250% more gas sensitivity than traditional two-detector pulsed neutron tools, the Raptor™ system delivers accurate and actionable reservoir saturation curves. Rather than a fuzzy, qualitative interpretation of what lies beyond the casing, our technology defines oil and gas volumes within a few saturation units.
The Raptor reservoir saturation tool uses enhanced sigma and carbon-oxygen (C/O) techniques for oil-water saturation measurements in saltwater and freshwater formations. It uses a proprietary N-vision technique to quantify gas-liquid saturation.
The Raptor tool consists of a pulsed neutron generator, four spectroscopy sensors―each containing a lanthanum-bromide (LaBr3) scintillator―and a fast-neutron counter. The Raptor reservoir saturation system, however, is more than hardware. We created new petrophysical methodology to support the most sensitive pulsed neutron tool ever built. Once the raw data reaches the surface, we begin our petrophysical workflows that ultimately provide precise and understandable answer products.