During production operations in heavy oil and bitumen formations where thermal recovery methods are applied, the fluids produced are often in the form of emulsions. This is also true in non-thermal recovery methods whenever oil and water are coproduced, but to a lower degree of severity. Conventional flow measuring devices are capable of measuring oil and water streams when they are segregated, but they fail when oil-in-water or water-in-oil emulsions form. Conventional methods are also not reliable when there are solids flowing in the stream. Low field NMR relaxometry was successfully tested as a tool for accurately measuring the oil and water content of such streams with and without emulsions present in the samples. The method was proved to be at least as good as conventional extraction methods (i.e., Dean-Stark). The technology was tested with both artificially and naturally occurring emulsified streams with accuracy better than 96﹪. This extremely encouraging result led to the design of an online NMR relaxometer for oil/water stream measurements under the conditions encountered in the production of heavy oil and bitumen. Introduction In the recovery of bitumen, viscosity reduction becomes important, both below and above the ground. The addition of a liquid diluent is thought to break down or weaken the intermolecular forces which create high viscosity in bitumen(1). The effect is so dramatic that the addition of even 5﹪ diluent can cause a viscosity reduction in excess of 80%; thus, facilitating the in situ recovery and pipe line transportation of bitumen. The knowledge of the bitumen-diluent viscosity is highly important, since without it, calculations in upgrading process, in situ recovery, well simulation, heat transfer, fluid flow, and a variety of other engineering problems would be difficult or impossible to solve. This paper presents the development of a simple correlation to predict the viscosity of binary mixtures of bitumen-diluent in any proportion. Experimental The data used for the development of the correlation was TABLE 1: Bitumen data at 30 °CDATA[C. Available In Full Paper. TABLE 2: Diluent data at 30 °CDATA[C. Available In Full Paper. obtained from Wallace et al.(2) and Wallace and Henry(3).The data consisted of a total of 99 points obtained from three bitumens and five diluents, respectively, listed in Tables 1 and 2. Each of these bitumen samples was diluted at 30 °CDATA[C to 5, 10, 25, 50 and 75 weight ﹪ diluent with each of the diluents. After mixing, the samples were reweighed, and any weight loss was attributed to solvent evaporation. The diluent weight fractions were adjusted accordingly, and the viscosities of the mixtures measured. For a detailed account of experimental procedures, refer to Wallace and Henry(3). Correlation Development Many correlations have been developed to predict the viscosity characteristics of bitumen-diluent mixtures(1-6). While several have been successful in making these predictions, most are cumbersome to use. Low Field Nuclear Magnetic Resonance (NMR) relaxometry techniques were developed in the laboratory to enhance and support comparable NMR logging tools that are currently used downhole.

Enhancing oil extraction from oil sands with a hydraulic fracturing techniquehas been widely used in practice. Due to the complexity of the actual process, modelling of hydraulic fracturing is far behind its application. Reproducingthe effects of high pore pressure and high temperature, combined with complexstress changes in the oil sand reservoir, requires a comprehensive numericalmodel which is capable of simulating the fracturing phenomenon. To capture allof these aspects in the problem, three partial differential equations, i.e., equilibrium, flow, and heat transfer, should be solved simultaneously in afully implicit (coupled) manner. A fully coupled thermo-hydro-mechanical fracture finite element model isdeveloped to incorporate all of the above features. The model is capable ofanalyzing hydraulic fracture problems in axisymmetric or plane strainconditions with any desired boundary conditions, e.g., constant rate of fluidinjection, pressure, temperature, and fluid flow/thermal flux. Fractures can beinitiated either by excessive tensile stress or shear stress. The fractureprocess is simulated using a node-splitting technique. Once a fracture isformed, special fracture elements are introduced to provide in-planetransmissivity of fluid. Effectiveness of the model is evaluated by solvingseveral examples and comparing the numerical results with analytical solutions.The model is also used to simulate large-scale laboratory hydraulic fracturingexperiments. Introduction Hydraulic fracturing technique has been a fast growing technology since itsfirst application in 1947. By 1988, more than one million hydraulic fracturingtreatments had been performed(1), and today this technique is one ofthe most important methods in enhancing oil extraction from wells. Hydraulicfracturing in oil and reservoirs plays an even more important role. Due to lowtemperature and low permeability of oil sand deposits and high viscosity ofbitumen, oil is virtually immobile(2). Hence, any attempt for insitu oil extraction should employ one of the following techniques: cyclic steamstimulation, in situ combustion, or hydraulic fracturing. Despite the fact that hydraulic fracturing technology has advancedsignificantly over the past fifty years, our ability to model the process hasnot changed as rapidly. As a matter of fact, this technique has been sosuccessful that in the past, designing the treatment with a high degree ofprecision was not of any interest. ut as the industry moved towardsapplications of very high volume/rate, and highly engineered and sophisticatedhydraulic fracturing treatments, the demand for more rigorous designs in orderto optimize the procedure have become more important. On the other hand, without a thorough understanding of the physical process and the factors thatare involved, our ability for an optimal design is limited. Modelling fluidflow combined with heat transfer in the reservoir has been used by the industryfor a long time, and the fracturing process was often designed based ontwodimensional closed-form solutions, such as Geertsma-deKlerk(3), or GdK in brief, and Perkins-Kern(4) and Nordgren(5), or PKN.

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We have developed a new on line water cut meter using low field Nuclear Magnetic Resonance (NMR) technology. This instrument is designed for use on heavy oil systems where conventional instruments experience difficulties. We present laboratory and field data for application of low field NMR to water cut measurements of bitumen/water mixtures. Data from successful field tests near Cold Lake, Alberta, Canada, shows that the instrument is capable of making water cut measurements over a wide range of fluid types and temperatures. We have successfully measured fluid streams with temperatures ranging from 60 to 150 degrees Centigrade and with water cut ranging from 40 to 95 percent. The instrument is capable of functioning accurately over a wide range of emulsions and/or foams and through significant variations of water salinity. The current application is for water cut measurements on a well site. However, the instrument can be applied in any system where heavy oil, bitumen, water, gas and solid systems may be encountered. It can be used for water cut and/or for three phase (oil/water/gas) volume fraction measurements. The instrument is equally capable of performing well site monitoring for regulatory/reconciliation purposes, for characterizing produced fluids, in separation, pipelining and upgrading processes for process control and for quality testing. Introduction One of the most challenging problems in the production and processing of heavy oil and bitumen is the task of measuring the flow of oil and water. Most instruments have been designed for conventional crude oils and perform poorly when applied to heavy and viscous hydrocarbons. We have developed a new water cut measurement tool specifically for use on heavy oil and bitumen streams. This tool is based on low field Nuclear Magnetic Resonance (NMR) and has shown great promise1 as an on line tool in use at a field in northern Alberta, Canada where bitumen in being produced using cyclic steam injection. This project is an extension of considerable experience in the lab with core analysis2–7. The initial stages in this particular project have been discussed elsewhere1,7. In brief initial experiments consisted of measuring both known and unknown discrete samples of oil/bitumen and water mixtures in a lab NMR instrument similar to what was used here. Some measurements were also made using unknown samples collected at the wellhead and placed in the instrument with no further preparation. Excellent correlations between NMR measurements and Dean-Stark analysis (approximately 99%) have been reported from this work.1,7 The next step was to build an on line tool based on this technology. The field results are reported elsewhere1, but the results have generally been viewed as excellent with this technology being in general at least as accurate as other tools typically used on these types of oil fields. This paper attempts to explain the technology and how it works.