Natural gas is always explored along with oil exploration in Huanghua depression. The third resource evaluation indicated that natural gas resources in the depression arc abundance. Though the proven reserve is low, the residue potential is large. Those resources are mainly distributed in Banqiao and Qikou sags find the depth of reservoirs is more than 3 500 m. At the same time, coal bearing series strata in upper Paleozoic distributes within all basins, so coal-genetic gas is also abound.
This article introduces the general outline of Dazhangtuo Underground Gas Reservoir (UGR) , summarizes and analyzes the mode of management and operation for this reservoir. From beginning of being putting into service at the end of 2000 till March of 2003, its sum total amount of gas injection is 0. 825 billion cubic meters, and of gas recovery is 0. 803 billion cubic meters. Its recent operation principle is as follows: I Absorption capacity of injection well is influenced by the effective permeability .
The development effect of Qianmiqiao buried hill condensated gas reservoir shows that it is with serious heterogeneity. Thus the current difficult issues for exploration and development mainly lie in the aspects such as analyzing and detailedly defining the top surface structure of the buried hill from the geological view in order to get full and clear understanding of the structure genesis and style inside Ordovician, carrying out researches like the reservoir description and evaluation of buried hill.
Coal-bearing Formations in upper Paleozoic distributes extensively with large thickness, high organic matter abundance and high hydrogen content in maceral. Especially in southern area of Huanghua depression, the source rocks is completely preserved, and being continually subsided, with better condition of secondary hydrocarbon generation, so that it is the advantaged zone for exploring coal-related gas. The resource calculation indicates that natural gas resource volume is 1 994×108 m3 from secondary hydrogen.
Natural gases gathered in Paleozoic group in southern Huanghua depression, which sourced from contemporaneous coal-bearing series in marine or limnic sequences, experienced complicated migration and charging history along with tectonic evolution through Mesozoic-Cenozoic era. The accumulation process, filling mechanics and alteration of remigration pathway for reconstructing of gas pool are inevitably controlled by structural deformation during Indosinian, Yanshanian and Himalayan cycle.
According to organic petrology, sedimentology and organic geochemistry of coal-bearing source rocks in Dagang fields, the depositional organic facies of coal-bearing source rocks can be divided into four types: highstand swamp, shallow-swamp forest, deep-swamp forest and flowing water swamp facies. Among them, flowing water swamp facies is characterized by high liptinite content and large hydrocarbon-generation potential and strong oil generation ability. Forest swamp facies makes up the main type.
This paper is focused on the geological characteristics of Qianmiqiao buried hill condensated reservoir. It’s a composite reservoir formed mainly by saturated one with middle-high condensate. It’s a residual mountain(unaka) which were a set of thrust blocks under the erosion unconformity. It’s reservoir pore space is a fracture-vug-pore system of Ordovician carbonate karst. The fluid distribute like layer in Fengfeng formation and up-Majiagou formation in top of Ordovician. This reservoir has high temperatuer.
Qianmiqiao buried hill condensated gas reservoir is an important discovery at the end of 20th century in Bohai Bay basin. Because the reservoir lithology is carbonate rocks, the pore type includes matrix pore, fractured pore and vug pore, it is hard to make quantitative reservoir evalu- ation. With the development of the imaginery logging technology (particularly the micro-resistance imagery logging FMI), the geological phenomena near well walls can be evaluated quantitatively and directly.
Based on status of Banqiao exploration, according to natural gas origin, evolution, source-reservoir-seal assemblage, hydrocarbon phase characteristics, natural gas reservoir types are divided. After the summary of condensoted gas accumulation, the authors conclude that good source is the basis; the specific background leads to deep gas phase; secondary porosity offers the effective space; high pressure is the driving force of migration and accumulation and large-scale structural background offers.
Banqiao rupture structural belt is located on the eastside of Banqiao sag, which is controlled by Banqiao and Dazhangtuo faults. This belt is abundant in natural gas which is generated from in-situ hydrocarbon source rocks, but is mainly from Banqiao sag. In this sag, the gas supply is abundant with high abundance of organic matter, good types of parent materials and complete evolution series of hydrocarbon source rocks. The sag is characterized with the early trap-generation time (which provides good settings.
Based on the geological characteristics and thermal evolution of natural gas in Dagang exploration area, this study has classified genesis of natural gas into six categories: biogenetic gas, low-temperature mixture gas, low-matured gas, matured gas, high matured gas, and coal-genetic gas. In addition, this paper has analyzed the distribution and geochemical characteristics of various kinds of natural gas in Dagang exploration area.
Wumaying buried hill is a deeply buried one situated in south of Huanghua depression. Commercial gas reservoir originated and stored in Paleozoic was found at the weathering crust on the top of Ordovician when drilling Wushen-1 well. It’s natural gas mainly originated from coal-bearing formation of C-P; Carbon isotope analysis, gas drying coefficient and naphthene index show that there is diversity in maturity of different component of the gas and the reverse carbon isotope series of gas.
The application of \"bright spot\" technique in seismic detection of upper Paleozoic clastic rock gas layers in Ordos basin is greatly restricted due to deep burial depth of target formations, small thickness of gas layers, small wave impedance differences between surrounding rock and gas layer, and no apparent physical property or fluid interfaces, etc. To bring into full play of the sensitivity of prestacked seismic information in detecting gas reservoir, the response characters of gas reservoirs are studied.
There are many successful examples on applying the seismic bright spot reflection to make a direct detection for the gas reservoir both domestic and abroad, and this has really brought good exploration benefit. However, with the complicated underground situation the bright spot exploration once failed even in such a mature area for bright spot exploration like Gulf Mexico. In the author’s opinion whether an oil and gas field can be conducted with reservoir seismic detection mainly dues to the vertical sequelea.
Qianmiqiao buried hill was found in the end of 20th century in Dagang oil field, which is a big north inclination monoanticline structure limited by three boundary faults with moderate condensate oil content. The target zones are Fengfeng group and Majiagou group of Ordovician system. At the beginning, the yield was higher, but the pressure and production were lapsed sharply. There are more differences among wells . The liquid compose was studied from the content of condensate oil, WGR and dissolved WGR experience.
Depleted way is main producing method for condesate gas reservoir besids a few kinds of there reservoirs being produced by gas-cycling in China. A big problem of depleting producing is making low condensate oil recovery. Lab experiment and development test on spot have been done in Banqiao oil field. It is show that formation waste water injection is a feasiblity way to improve condensate oil and gas recovery for abandened condensate gas reservoir. More about 3. 39 percent condensate oil and 10. 11 percent .
Qianmiqiao buried hill condensated gas reservoir is consists of the carbonate rock. Enhancing gas well producibility by acided-fracturing is the necessary measure of all Qianmiqiao bruied hill condensate gas reservoir prospect and exploitation well. The analysis of the acided-fracturing effect by the transient well test prove to be not all the reservoir that has not the high producibility, the reservoir damage is the dominating factor of the affecting acided-fracturing effect, and that the acided-fracturing...
As a new kind formation disposal technology of near well-bore zone of condensated gas well, the plugging relieved mechanism of down-hole electromagnetic induction heating mainly makes use of the increase of formation temperature of near well-bore zone to relieve the effect of well-bore liquid accumulation on productivity. According to the percolation law and exploitation characteristics of condensate gas reservoir, on the basis of percolation motion equation of oil, gas and water, energy conservation .
Condensated gas reservoir with oil rim (condensated gas cap reservoir) is one of the most complex oil and gas reservoir type. It is of same complexity in development and dynamic reserve calculation. This article follows the principle and analytical method of modern oil and gas reserve engineering, in combination of new method and new technology of similar oil and gas reservoir development in China and overseas, and take the example of Banzhong north high point condensated gas reservoir to conduct the dynamic.
Qianmiqiao buried hill condensated gas reservoir in Dagang oil field, eastern China, was an important discovery at the end of 1998’s exploration. The oil and gas production was high at the beginning stage, but production rate and formation pressure dropped down quickly accompanied with GOR and water cut increasing rapidly. These appearances fully reflect that Qianmiqiao buried hill condensate gas reservoir is very complicated. The single-well model was made using numerical simulation on the basis.
Banqiao condensated gas field which is a kind of special hydrocarbon reservoir of complicated faulted block now enters its later developing period, various contradictions are becoming intensified gradually. In addition, production wells that lie in both bitterns pool within salt field and shoals region as well as the majority of wells are clustered well. All these have restricted the developing effectiveness of the whole oilfield. A thorough analysis and adaptive appraisement have been made on current engineer.
Coalbed gas development was made great success in Dacheng highs within Cangxian uplift. As the same setting, on the southern parts of Cangxian uplift, coaly beds in upper Paleozoic are preserved in good condition and stable distribution in Dagang fields. The coaly beds area less than 2 000 m is about 1 500 km2. The estimate of benefit coalbed gas resources is 3 228×108 m3, so that there is great potential of coalbed gas in Dagang oil field.
甘公网安备 62010202000678号
