Characterizing multi-layer reservoirs using a fast computational simulator and a new environmentally sensitive pre-production well test /
In this work, we address the needs of the industry, especially in the North Sea reservoirs and environmentally fragile areas, for a simple, inexpensive and environmentally sensitive technology to characterize and model multi-layer reservoirs with unequal initial pressures. We present the general sol...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739663321&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | In this work, we address the needs of the industry, especially in the North Sea reservoirs and environmentally fragile areas, for a simple, inexpensive and environmentally sensitive technology to characterize and model multi-layer reservoirs with unequal initial pressures. We present the general solution in Laplace space for a commingled reservoir with unequal initial pressures. We derived the Laplace space solution in terms of individual layer source/Green's functions. We used the Green's function to handle the inhomogenous initial boundary conditions resulting from the effects of unequal initial pressures. We developed a fast semi-analytical simulator, MLSIM, for modeling multi-layer reservoir performance including pre-production, constant rate drawdown for layers with equal initial pressures, and constant rate drawdown for layers with unequal initial pressures. The reservoir performance information available from this model includes wellbore pressures, pressure derivatives, individual layer flowrates, and layer cumulative production. The semi-analytical simulator proved to be faster than a conventional threedimensional, finite-difference commercial simulator. Also the amount of information needed to run the model is much reduced. We designed a new pre-production well-test, PPWT, for analyzing a commingled reservoir with unequal initial pressures. The pre-production well test needs only a pressure gauge above the top layer. This test reduces cost and time substantially compared to conventional multi-layered testing techniques. Also, as there is no production on the surface, the new well test is well suited for offshore wells or for testing wells in environmentally sensitive areas. We developed analysis techniques and methodology to analyze the PPWT performance. The Modified Semilog Method, MSM, analyzes the pressure data from two-layer infinite-acting reservoirs to determine the fractional mobility-thickness ratio. The Derivative Extreme Method, DEM, has the advantage of determining the individual layer properties and not the ratios of properties from the transient and late-transient time region data. The Integrated Modified Derivative Extreme Method, INMEM, determines the layer drainage areas in addition to the layer permeabilities and layer skin factors. The Rate Normalized Method, RNM, can handle any number of layers, but it requires that pressure and rate data be recorded. We verified these analysis methods by six test cases from the literature. These cases demonstrated the applicability and validity of the pre-production well test analysis methods. |
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| Item Description: | Vita. "Major Subject: Petroleum Engineering". |
| Physical Description: | xix, 327 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |