A New Small-Diameter, High-Performance Reservoir Monitoring Tool

The parameters of C/O ratio and Sigma based on pulsed neutron source can be obtained at the same time in one logging, which utilizes a special pulse and measurement timing design to record inelastic, capture gamma ray spectra and gamma ray time spectrum at the far and near detector. By combining dual parameters for determining oil, water and gas saturation, it can resolve the problem no way to distinguish gas and water only using C/O, oil and fresh water only using Sigma, in addition, it can determine saturation under the condition of unknown borehole porosity information. By theoretical analysis and Monte Carlo simulation method, the gamma ray time spectrum after repetitive pulse of neutron emission can still meet the exponential decay law, and repetitive pulse before neutron lifetime measuring can raise gamma count rate of time spectrum 3 to 5 times, therefore, the dual parameters measured simultaneously in one logging are feasible. Through dual parameters of C/O ratio and Sigma, the C/O data is cross plotted against Sigma data and then to determine oil, water and gas saturation. By using Monte Carlo method to set up computation model, inelastic gamma spectrum, capture gamma spectrum and time spectrum under certain borehole and formation conditions can be simulated, and the logging response is given when determining oil, water and gas saturation by using cross plot technique of C/O and Sigma. In addition, the influence of lithology, porosity, shale content, borehole size, formation water salinity and gas density on determining saturation were simulated, and it will provide response relation for determining oil saturation by dual parameters of C/O ratio and Sigma.

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A Novel Technology for Locating and Evaluating Hydraulic Fractures in Horizontal Wells – Modeling and Field Results

Zhang

Smith

Palisch

et al. 2018

SPE Annual Technical Conference and Exhibition

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Non-radioactive tracer tagged proppant technology has been used successfully in over 200 vertical wells to obtain fracture height and gravel pack coverage, but had yet to be modeled or tested in horizontal wells, where the borehole and fracture geometry is radically different. The purpose of this paper is to demonstrate the effectiveness of this new technology to locate proppant placement and to evaluate the efficiency of perforations and clustering in fracturing operations in horizontal wells. The new technology utilizes a pulsed neutron capture (PNC) logging tool to detect the tagged proppant, which has a high thermal neutron capture cross-section. Monte Carlo software is utilized to simulate the responses of different pulsed neutron measurements to vertical fracture planes along a horizontal wellbore. The tool responses were analyzed and the best PNC measurement parameters were determined for locating proppant placement in the fractures, and hence for determining perforation and cluster efficiency. A field test was the conducted to validate modeling results in a horizontal well with multi-stage fracturing operations. Modeling data and the field log example show that it is feasible to use the taggant and a PNC tool to locate proppant placement and determine the efficiency of perforations and clustering in horizontal wells. Furthermore, the analysis of the depth intervals of tracer signals and the known axial and radial resolutions of the PNC measurements show that the depth interval of tracer signals along the wellbore may provide a qualitative indicator of one or more of the following: (1) the presence of multiple fractures opposite perforation(s), (2) the angle between the wellbore axis and the fracture plane for ideal conditions (e.g. the more narrow the tracer signal along the log, the closer the fracture plane is to being perpendicular to the wellbore axis), and/or (3) proppant placement in the borehole region. Moreover, a new near-wellbore connectivity index has been developed based on identifying and using the most suitable PNC log parameters for the evaluation. The index indicates how well the induced fracture is connected to the wellbore at locations of all perforations/clusters. The field test demonstrated that this new technology met all of the operator's objectives, with tracer signals clearly observed in all stages. This paper will present the modeling work and the results from the field test. The new non-radioactive proppant tracer technology provides for the first time the ability to evaluate proppant location in horizontal wells without encountering the health, safety, and environmental issues associated with using radioactive tracers. The determination of proppant placement and perforation efficiency, and a near-wellbore connectivity index, can be employed to evaluate the success and effectiveness of individual perforations and stages, and to optimize future completion designs and processes for enhancing hydrocarbon recovery.

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A New Small-Diameter, High-Performance Reservoir Monitoring Tool

Cited by 6 publications

References 0 publications

Formation Evaluation Through Casing

Formation Evaluation Through Casing

Simulation on the Method of Determining Remaining Oil Saturation by Measuring Dual Pulsed Neutron Parameters

A Novel Technology for Locating and Evaluating Hydraulic Fractures in Horizontal Wells – Modeling and Field Results

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