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Abstract Buried hill gas reservoir with bottom water of Y5 has a high CO2 content of 92.88-99.80%, in which structural fractures and solution cavities are relatively developed. On the basis of testing data of three times, this paper analyzes well testing characteristics of the reservoir. 1) Through comparison between observation results of flowing pressure & temperature gradients and lab analysis, it could be seen that phase behavior of flowing CO2 column has obvious difference with that of static one. Under the circumstances of above critical conditions of CO2, high-density fluid, including liquid water, gaseous CO2 and hydrates, has been appearing in the well bore. Liquid state CO2 begins to be formed at the depth of 265.80m or so, when critical conditions are reached. Influenced by those, pressure loss in well bore is severe comparatively. 2) Per-well gas rate is relatively low and the base of stable production is obviously poor. And, 3) Commingled production of two layers could remarkably reduce gas deliverability. It could be concluded through studies of twice floe-after-flow test data, 1) Production results of single zone are superior to those of multiple-zone. 2) Steady or pseudo-steady states are not reached during well testing, as a result of low reservoir permeability and insufficient testing duration. And, 3) Reservoir pollution is stepping down as test was in progress. Finally, reasonable initial per-well gas rate are discussed from many aspects, and major measures to increase gas rate are put forward, that is, reducing pollution through adoption of acidizing reservoir to dissolve blockageand improve capability of gas flow carrying liquid by introduction of slim tubing to increase velocity of flow in thewell bore. Introduction Development of CO2 gas reservoir is increasingly paid more and more attention. Because of its special phase behavior, methods of well testing and evaluation of CO2 gas reservoir are different from those of conventional hydrocarbon gas reservoirs. In the interest of exploiting and utilizing CO2 resources scientifically and reasonably, this paper analyzes well testing characteristics of gas well of Yang 5 buried hill CO2 gas reservoir based on testing data for three times. And initial rational per-well gas rate is discussed from four aspects, thus main measures to improve gas rate are brought forward. Yang 5 buried hill CO2 gas reservoir is situated at Huimin County, Shandong Province, East China geographically, and is located on Balipo buried-hill belt of west Yangxin Sag ofJiyang Depression structurally. The seismic exploration in this area began in 1965, with 2D (two dimensional) seismic grid of 1.2km × 1.2km, locally reaching 600m × 600m and areas of 3D (three dimensional) being 333km. Presently, three exploration wells are drilled, in which 2 wells got commercial gas flow (Well Yang 2 and Yang 5). It is a typical high-purity CO2 gas field, with proven original gas in place (OGIP) of 1.516 ? 10m. Structural and Stratigraphical Features Structure Yang 5 buried hill is a monadnock-fault buried hill of Low Paleozoic in Yangxin Sag, and east-southeast boundary is a large fault with fall over 1000 m.
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- Reservoir Description and Dynamics > Fluid Characterization > Phase behavior and PVT measurements (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
Abstract Knowing the injection profile of each injector in a reservoir is of major importance for analyzing residual oil distribution, which is the foundation of IOR project design. However, in practice, it is impossible to acquire real-time injection profiles for each well when we need it. In this paper, a new method using fuzzy mathematical theory is introduced, to predict injection profiles for wells with outdated or no related information by analyzing those injectors whose injection profiles are well characterized. Three pivotal factors were selected as an evaluation factor set: sand-body type, communication with surrounding oil wells and well spacing. Based on the statistical results for those wells with wellcharacterized injection profiles, three standard diagrams were constructed based on the relationship between the relative water absorption of each layer and each evaluation factor.
An analytical model of fuzzy mathematics for the prediction was then constructed. Fuzzy subsets were based on those standard diagrams, and a weighting set was obtained by trial and error. To verify this proposed method, some injection profiles were predicted from two blocks in the Daqing oilfield. Their average accuracy was shown to be above 75%. The results from this method have been applied successfully to analyze residual oil distribution in a block and to designperforation projects. An example from infill well projects has been successfully carried out in one block, improving oil recovery by 4.5%.
Introduction During the analysis of remaining oil, a key factor is to beat out the water absorbing capacity of each subzone in every water injection well. At present, many water injection wells have no test data or have farness test duration, so the water absorbing capacity of each subzone could not be reflected factually. Each subzone of water injection well is a fuzzy system. Because of the effect of reservoir depositional character and development factor as well as the effective factors are very complex, and they could not be expressed by quantitative mathematical relational expression, so fuzzy comprehensive judging method is suitable to be used in evaluating the water absorbing capacity of reservoir.
Principle of Fuzzy Comprehensive Every influential factor is called an appraisal object. Appraisal results are denoted by a group of fuzzy sets on remarks. This group of sets is called remark set. Recorded as V={v, v, v,..., v }. The set constituted by all the factors that have some effect on appraisal result is called factor set. Recorded as U={u, u, u,..., u}. The evaluation based on u is called single factor evaluation. Recorded as r= {r, r, r,..., r} i=1,2,...n. This single factor evaluation can only reflect one aspect and could not reflect the total instance. But n factors have n single factor evaluation vector, they are composed to be a fuzzy matrix that called judging matrix: R=(r)n_m, suppose a fuzzy vector: X= {x,x,x,...,x} 0
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Yian Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Mingshui Formation (0.99)
The Establishment and Application of Binomial Deliverability Equation for Horizontal Gas Well
Li, X. (State Key Laboratory of Oil/Gas Geology and Exploration Engineering of Southwest Petroleum Institute) | Huang, B. (State Key Laboratory of Oil/Gas Geology and Exploration Engineering of Southwest Petroleum Institute) | Hu, Y. (Geology Research Institute Sichuan Petroleum Administration)
Abstract The horizontal gas well has more and more important roles in developing low permeability gas reservoirs, fractured gas reservoirs and bottom-water gas reservoirs. The productivity forecast of horizontal gas well is an important research work in aspect of its gas reservoir engineering. Based on gas underground percolation theory, considering formation damage and non-darcy effect, this article establishes the mathematical model of horizontal gas well production rate analysis, on the basis of obtaining the mathematical model solution, i. e. production rate equation of horizontal gas well, we derive binomial productivity equations with the forms of pressure square, thus, we can forecast inflow performance relationship(IPR) curve absolute open flow potential and production performance of horizontal gas well by using the binomial productivity equations. At the same time, we study the influences of the gas reservoir bed thickness, anisotropism of gas reservoir on the inflow performance relationship(IPR) curve and absolute open flow potential. Inflow performance relationship(IPR) curve of an example horizontal gas well is made in this paper. The binomial productivity equations presented in this paper supply the foundation for calculating and forecasting the productivity performance of horizontal gas well. Introduction So far, in the world, more and more special oil and gas reservoirs are developed through the horizontal well, both the horizontal oil well and the horizontal gas well, analysis methods of their productivity are important research content. Recently several years, many scholars studied productivity of the horizontal oil well, their methods contained that method of Joshi and method of Babu. At the present, analysis method of the horizontal gas well is not reported. Based on gas underground percolation theory, considering formation damage and non-darcy effect, this article establishes the mathematical model of horizontal gas well production rate analysis, on the basis of obtaining the mathematical model solution, i.e. production rate equation of horizontal gas well, we derive binomial productivity equations with the forms of pressure square, thus, we can forecast inflow performance relationship(IPR) curve, absolute open flow potential and production performance of horizontal gas well by using the binomial productivity equations. At the same time, we study the influences of the gas reservoir bed thickness, anisotropism of gas reservoir on the inflow performance relationship(IPR) curve and absolute open flow potential. Inflow performance relationship(IPR) curve of an example horizontal gas well is made in this paper. The binomial productivity equations presented in this paper supply the foundation for calculating and forecasting the productivity performance of horizontal gas well. MATHEMATICAL MODEL OF HORIZONTAL GAS WELL PRODUCTION RATE EQUATION Fig.1 shows a schematic picture of horizontal well. To set up mathematical model of horizontal gas well steady flow, we establish the following additional hypotheses: (1) The gas reservoir is horizontal with constant uniform thickness(h), horizontal permeability (Kh) and vertical permeability (Kv), the initial pressure is equal to constant (PR). (2) Horizontal gas well located at a distance δ z from the gas reservoir center and paralleled with upper and lower impermeable, its length isL.
Abstract An experiment was initiated in 1997 in northeast Alberta at Syncrude Canada Ltd. Mildred Lake site to field test an innovative technique for reclamation of oil sands mine tailings. This technique was used to create an aggregated surface soil material from oil sand tailings. Plant community was successfully established on soil material created by this technique. However, whether the site would be capable of supporting a self-sustainable ecosystem for the long-term remained unknown. We evaluated the capability of these aggregated oil sands tailings by using biological indicators because the abundance and diversity of soil microbial biomass is a good measure of the health of soil-plant ecosystem. Soil respiration rates and soil microbial biomass were used to assess the abundance and activities of soil microbial communities. In addition, the ability of soil microbial biomass to utilize a diverse range of carbon substrates was used to assess the diversity of soil microbial communities. Soil biological activity increased with increasing growth of plant biomass and with time. Increasing amount of peat moss incorporated into the soil during reclamation resulted in higher organic carbon and nitrogen content and caused an increase in abundance and diversity of soil microbial biomass. These results indicate that measurements of soil respiration and substrate utilization by soil microbial communities may be used as biological indicators for assessing the capability of reclaimed soils. Introduction One active area of land reclamation research is to compare and synthesize patterns and processes in reclaimed soils and to assess their capability for supporting a self-sustaining ecosystem. Such comparisons and synthesis work best only when the measurements made are comparable and repeatable (Robertson et al., 1999). Using a standard methodology is a key to addressing many questions regarding longterm sustainability of reclaimed land. A critical component in the reclamation of oil sands tailings is to create soil materials conducive to the growth of soil microorganisms and as a result, to stimulate soil microbial biomass mediated nutrient cycling process following initial reclamation. Soil organic carbon dynamics is at the center of these processes. Soil microbial biomass is largely responsible for the decomposition of soil organic matter and litters that contribute to soil nutrient pools through mineralization. Additionally, certain soil microorganisms form symbiotic associations (mycorrhizae, nodules) with plants and contribute to the overall success of plant growth. Thus the success of planting for reclamation purposes is affected by, and may be contingent upon, the quality and quantity of soil microbial communities and their activities. This paper presents the use of a few simple measurements of soil microbial activities as biological indicators for evaluating the capability of reclaimed soil. MATERIALS AND METHODS Field Site The site, located at the Syncrude Canada Ltd. Mildred Lake in northeastern Alberta, was established in 1997. Composite tailings (CT) weres used as a sub-material. Five treatments were used for the top 20 cm layer. The composite tailings, amended with various amount of peat moss, were aggregated using an aggregation technology (Li and Fung, 1998).