[en] Based on brief explanation of the measurement principle for nuclear magnetic resonance (NMR) logging, this paper illustrates the importance of NMR logging in reservoir evaluation through typical case examples. These case examples include: Reservoir characterization and productivity evaluation by using NMR logging, determination of reservoir porosity in complex lithology, identification of oil, water and gas zones under complex reservoir conditions where resistivity log data give poor indication, guiding the implementation of completion and drilling programs, etc. Excellent application results indicate that NMR logging has its special features and advantages in comparison with conventional logging techniques. It is a very practical and very promising logging technology

[en] In this paper the inversionn of nuclear-derived chemistry into quantitative mineralogy is considered. The roles of mineral choice and individual mineral composition are shown to be important in estimating an accurate modal mineralogy. Compositional colinearity in which three or more of the phases sought lie on, or close to the same compositional plane, can produce unstable mathematical solutions. The absence of water and carbon dioxide data together with the inability to measure Na and Mg individually contribute additional difficulties to the inversion process. Despite these concerns a geologically meaningful mineralogy may be produced, though adequate validation of a particular solution still remains

[en] Very little information exists regarding evaluating enhanced oil recovery (EOR) projects, in particular miscible floods. Due to the size and scope of most tertiary recovery projects, standard evaluation rules and techniques are too general and vague to adequately model these schemes. A procedure for identifying the risks associated with miscible EOR projects is presented. It is essential to set up a cash flow model that accurately represents the future performance of a miscible flood. Included in the model are the timing of crucial events such as expected solvent breakthrough and the injection of trace gas. The cash flow analysis allows a quick audit procedure and converts production into a monetary or economic evaluation criteria that can easily be compared to other investment alternatives. When evaluating a miscible flood project, forecasting production, solvent and chase gas recovery costs can become quite complex. An organized procedure for an evaluation will ensure that a comprehensive and thorough examination of all the data is completed, and will increase confidence levels associated with decision making. 32 refs., 4 figs., 4 tabs

[en] The development of a new well stimulation technique that uses propellant technology was discussed. The enhanced oil production process involves igniting a cylinder of solid rocket propellant positioned across a perforated zone to disrupt clogging sand. The StimGun assembly is a hybrid method of perforating with simultaneous propellant stimulation. High pressure gas enters the perforated zone and breaks through damage around the tunnel creating fractures. Data recorders can also run with the StimGun to record downhole pressure and provide a data model for estimating rock properties and propellant penetration. The StimGun assembly was developed by Marathon Oil, Computalog Ltd., Owen Oil Tools, and HTH Technical Services Inc., and is available in Canada from Computalog. 1 fig

[en] This paper describes a method of measurement to be used in completing an open-hole frac procedure. Unlike cased hole work, a gamma ray---CCL log is used in correlation with a steel line measurement (SLM) to supply the completion rig crew with correct depths for placement of completion activities. This assures that the dollars spent for stimulation of the reservoir rock will be used to achieve the greatest results

[en] Determination of the current and residual oil saturation and the current oil recovery coefficient in cased production wells is usually based on a comparison of the pulsed neutron log data representing the up-to-date oil saturation and the reference pulsed neutron log obtained prior to the start of the well exploitation, thus representing the initial oil saturation. In situations when the reference pulsed neutron log is not available a model of this log is obtained through a combined statistical processing of the up-to-date pulsed neutron log and of some conventional logs recorded in the open hole of the same well prior to setting casing. Comparing the up-to-date and the model reference pulsed logs provides the determination of the current oil saturation and the current oil recovery coefficient, both supplied by statistically estimated probable errors. The data obtained provide, as well, an opportunity to delineate the oil-bearing layers which erroneously were believed to be utterly depleted or earlier were not tested, since from conventional log interpretation were considered to be nonproductive. (author)

[en] The oil and oil well logging companies have long been innovators in many technologies that are used in oil well logging. This includes the development and use of radiation detection equipment in the harsh environment of oil wells. It also certainly includes the use of Monte Carlo simulation in the study, optimum design, and calculation of corrections and correction factors for the inverse logging problem. This latter area is the subject of this paper. Past milestones in this area are discussed along with those of the present and future work. The perspective is from the viewpoint of the authors.

[en] Science and Technical Department of JSC Tatneftegeofizika has developed in 1999 an instrumentation-software system of pulsed neutron logging AINK- 36-3Ts which offers advanced capabilities in logging oil and gas wells. This system provides as follows: (i) multispaced (3 spacings) pulsed neutron gamma log; (ii) multispaced neutron activation oxygen log; (iii) natural gamma-ray log. Specific features of this system are as follows: use of symmetrical spacings (60 cm); use of PIC-processors in the downhole unit; and use of realistic adaptive models of a PNGL response. Basic instrumentation specifications of the system are as follows: yield of 14-MeV neutrons: 6.10⁷ n/s; modulation frequency of neutron bursts: 20 Hz; guaranteed serviceability period of the neutron tube: 100 h; outer diameter of the logging tool: 36 mm; total length of the logging tool: 3.1 m; number of spacings: 3 (30, 60, -60 cm); telemetry type: Manchester II. Preprocessing of the tool response is made in the downhole unit, next the digital information is transmitted to the surface and processed on a surface-based workstation. High stability of the neutron yield and two-exponent model applied in data processing allow one to produce parameter Σ_af with an accuracy of up to 5% and fluid production rate in well (from neutron-activation oxygen log) with an accuracy of up to 5%. This instrumentation-software system can be applied on oil-and-gas fields to solve the following problems: lithological analysis of productive formations and estimating their flow properties; controlling the position of WOC and GFC in pay zones under production; determining the residual oil-saturation in completely watered, originally oil- prone formations; identifying the hydrodynamic communication between perforated productive formations and above- and below-lying water-bearing beds. The use of symmetrical spacings provides a separate estimation of upward and downward water (or watered product) flow rates. The AINK-36-3Ts instrumentation-software system is presently subject to testing on the oil fields of Tatarstan. (author)

[en] This paper reports that three generations of Schlumberger's Thermal Decay Time (TDT^SM) logging devices - viz., TDT-K, TDT-M, and TDT-P - along with an Atlas Wireline PDK-100^SM system were run in a Saudi Aramco well. The wellbore (8 1/2 in. with 7-in. casing) penetrated a sequence of clean sand, shaly sand, and shale streaks as exhibited by the openhole natural gamma ray log. The initial wellbore fluid was diesel. The fluid was then changed to brines of 42,000 and 176,000 ppm NaCl, respectively. Three repeat passes at a logging speed of 900 ft/hr were obtained by each device for each borehole liquid. As a result of this extensive comparative study, a set of departure curves and mathematical transforms was developed primarily for standardizing the various Schlumberger tools to a common reference logging system and/or borehole environment. The transforms were used beneficially to determine residual oil saturation (ROS) from time-lapse logs in a Saudi Aramco reservoir

[en] The Tucker Wireline unit ran a suite of open hole logs right behind the RMOTC logging contractor for comparison purposes. The tools included Dual Laterolog, Phased Induction, BHC Sonic, and Density-Porosity