This paper presents a study on the use of radioactive tracers for steam vapor phase injection profiling. Field data show that methyl and ethyl iodide are not reliable vapor phase tracers because they decompose into water soluble tracers at steam conditions. Vapor phase injection profiles obtained with methyl and ethyl iodide are therefore incorrect. Radioactive inert gases (krypton, xenon. or argon) are recommended as vapor phase tracers. Field data using inert gases to trace the vapor phase identify gravity segregation problems in the wellbore. Techniques to measure downhole steam quality are discussed and field data presented. Introduction Thermal recovery is the most common enhanced oil recovery method in California. In designing a thermal recovery operation, one of the objectives is to deliver the correct rate of steam at the desired steam quality to the formation. However, as steam is being distributed from the generator to the well, it is subject to many factors: in the surface steam lines, two phase flow splitting phenomenal affect the quality of steam delivered to the wellhead; in and near the wellbore, gravity segregation and relative permeability affect the distribution of vapor and liquid to different completion zones. Since the vapor phase contains most of the thermal energy and comprises most of the volume of steam (Figure l), an accurate vapor phase injection profile is critical to evaluate steam injection designs. In the published literature, methods to measure steam injection profiles have not been fully evaluated. For example, steam injection profiles are commonly reported based on surveys which used a liquid phase tracer. Due to gravity segregation, a liquid phase injection profile is not sufficient to provide information on the energy profile in the wellbore. In this paper. we review the problems encountered when the vapor phase injection profile is measured with the existing technique. We then propose a new logging technique to accurately measure the vapor phase injection profile. We also propose a technique to measure the downhole steam quality. With measured downhole steam quality, wellbore heat loss and total heat injection profile can be calculated. EXISTING STEAM INJECTION PROFILING TECHNIQUE Radioactive tracers are commonly used to measure the steam injection profile. In most applications, sodium iodide and methyl or ethyl iodide are used as liquid and vapor phase tracers. (Methyl and ethyl iodide belong to the alkyl halide family.) Sodium iodide and alkyl halides are selected because they have been successfully used as radioactive tracers in water and gas injection wells. The steam injection survey is typically conducted in the following sequence: first, a gamma survey is conducted to record the background radiation level in the wellbore. A slug of tracer is then injected at the wellhead and travels with steam to the formation. After the tracer has moved past the gamma tool in the wellbore consecutive gamma surveys are run to record the gamma intensity over the completion interval. The steam injection profile is constructed by calculating the relative area under the gamma intensity signal at each zone. "results are presented in the form of percent of steam injected at each given zone. P. 205^

The water-alternating-steam process (WASP) was applied to vertical expansion (VE) sands in the pilot area of Section 13D, West Coalinga field to stop wasteful steam production and to improve vertical conformance of injected steam. Before the WASP application, steam breakthrough in the VE sands caused well sanding, cutting of downhole tubulars, and high-temperature-fluid handling problems. To alleviate these problems, pumps had to be raised in five wells and one well had to be shut in, reducing oil production from the VE sands and the lower waterflooded zones. A WASP field test, based on a numerical simulation study, was implemented in July 1988 with alternating slugs of water and steam, each injected over 4 months. The WASP eliminated steam production, allowing the pumps to be lowered and the one shut-in well to return to production. Oil production remained constant through the first WASP cycle and increased during the second cycle. Sales oil (total production minus oil used to generate steam) increased as a result of saving generator fuel during the water leg of each WASP cycle, resulting in improved project economics.

The intent of this study was to rigorously look at all of the possible expansion, investment, operational, and C02purchase/recompression scenarios (over 2500) to yield a strategy that would maximize net present value of the C02 project at the Rangely Weber Sand Unit. Traditional methods of project management, which involve analyzing large numbers of single case economic evaluations, was found to be too cumbersome and inaccurate for an analysis of this scope. The decision analysis methodology utilized a statistical approach which resulted in a range of economic outcomes. Advantages of the decision analysis methodology included: a more organized approach to classification of decisions and uncertainties; a clear sensitivity method to identify the key uncertainties; an application of probabilistic analysis through the decision tree; and a comprehensive display of the range of possible outcomes for communication to decision makers. This range made it possible to consider the upside and downside potential of the options and to weigh these against the Unit's strategies. Savings in time and manpower required to complete the study were also realized.

Problem Statement: An aging workforce and an increase in the incidence of disabling chronic illnesses may put the workforce at risk. Evaluation of worksite wellness programs and the assessment of an organization's health data provide a means of identifying and addressing the areas at high risk. Objectives and Scope of Study: This paper describes pilot implementation of a wellness scorecard in multiple business units. The scorecard can determine alignment of programming with wellness best practices and facilitate alignment with specific outcomes that are relevant to the business. Method: Corporate Health and Medical is piloting a wellness scorecard in a cross-section of business units. An evidence-based approach provides businesses with a standard health report card that can be periodically monitored to provide information on how wellness programming compares to best practices. The scorecard is also used as a communication tool to engage business leaders in discussions about the value of health to the organization and to assess where businesses are currently positioned in the development of a culture of health. Results and Observations: An overall score or profile is provided based on 4 general categories: leadership engagement and support; workplace policies and environment that support health and wellness; programs that address health and wellness, in terms of design and impact; and assessment of the evaluation approach. Participating locations are also provided with a simple report that describes the degree of implementation of these categories. For organizations with more robust programs, the scorecard provides a tool for monitoring changes in population health and alignment with best practices. For those at the initial stage of developing health and wellness programs, it has utility for engaging leaders around health and wellness. Conclusions: Such scorecards can describe key measures of organizational health and assess implementation of best practices. Applications: Business units can leverage Corp and local health and medical's expertise around programming, data privacy, legal and policy implications of wellness programs. Innovations or Technical Contributions: Provides standard processes for management engagement around health and enhances programming that support workforce health and well-being.

The Minas field in Central Sumatra is the largest field in Southeast Asia. Following completion of combined peripheral and pattern waterfloods there will be more than 4 billion barrels of oil remaining. P.T. Caltex Pacific Indonesia (CPI), Texaco, and Chevron carried out a joint effort to evaluate tertiary steamflooding of this 36 API oil reservoir. This paper describes the processes used to define potential project performance and to assess and reduce technical uncertainties. The evaluation was carried out in two Phases. Phase 1 used existing geologic and rock/fluid properties. A high-grading process was first developed for selecting that area of the field most suitable for steamflooding. For that area, detailed geological geostatistical models and detailed numerical simulation models were constructed for forecasting production. Uncertainty ranges in key geologic and rock/fluid parameters were estimated and the sensitivity of the production forecast to those uncertainties was determined. A Decision Analysis was carried out to quantify the economic effects of the Phase 1 uncertainties and to estimate the value of better data. That analysis justified Phase 2 which included a more comprehensive geological characterization, laboratory and field measurements of waterflood residual oil saturation, and laboratory measurements of steamflood displacement parameters. A new production forecasts based on these results had a reduced uncertainty range and suggested that substantial amounts tertiary incremental oil may be obtainable by steamflooding in Minas. Introduction The Minas field in Central Sumatra (Fig. 1) is operated by CPI (jointly owned by Chevron and Texaco) under a production sharing contract with Pertamina the Indonesian National Oil Company. The field was discovered in 1944 and was first produced in 1952. The reservoir is in early Miocene sandstones in the Sihapas formation at an average depth of 2,000 ft. subsea with a maximum vertical oil column of 480 ft. Average porosity is 26 %. The oil is 36 API with an average initial bubble point pressure of 235 psig. Current reservoir pressure is approximately 350 psig. Reservoir temperature is 207 F. The original oil-in-place estimate is 9 billion barrels. Minas field was initially developed on 214 acre spacing. Initial production was by aquifer drive that was augmented by peripheral water injection beginning in 1970. Starting in 1978, infilling reduced spacing to 71 Acres. In the early 1990's, phased pattern waterflood development was implemented using 71 Acre inverted seven-spot patterns. This development is approximately 70% complete and is targeted only in the thickest parts of the field. Ultimate recovery following completion is estimated to be 51% of OOIP. The large volume of oil projected to remain after waterflooding has motivated CPI and Pertamina to consider post-waterflood recovery processes. A systematic screening process indicated that steamflooding is one process that has potential and should be studied further. This paper describes the result of that study. Focus will be on describing processes for selecting the best areas of the field for steamflooding, developing performance predictions that take into account uncertainty in reservoir and rock properties, and for focusing effort in more detailed measurements and studies. Why a Steamflood in Minas? Screening calculations for enhanced recovery methods in Minas show that many processes are unsuitable. For example, CO2 and hydrocarbon miscible flooding are negatively affected by the low reservoir pressure and high reservoir temperature. Chemical flooding methods (surfactants and polymers) may be technically feasible but have limited economic potential using chemicals commercially available in the U.S. because of high injectant costs. P. 257^