| Shapingchang structure locates at Liangping county and Dianjiang territory of Chongqing Province, which is a latent anticline tectonic in the north section of Mingyue gorge tectonic and footwall of fault in the south section of Datianchi tectonic. The proven reserves of Shapingchang carboniferous gas reservoir is 358.78×10~8m~3. Its accumulation gas production has come to 358.78×10~8m~3 since 1999. At present the exploitation of the gas reservoir is in the Mid-late development period. There are some main problems during the development of the gas reservoir. First, gas reservoir pressure, well production and formation energy has decreased rapidly.Second, edge water from the south and the west has invaded into the reservoir. Five production wells would be closed for the reason of the water influx. And Dynamic reserves of Shapingchang gas reservoir also need to be verified. The main work carried on as follows:1. On the basis of the core observation and logging interpretation results, this article has analysised the sedimentary facies, diagenesis and the fracture system and physical properties.2. According to the static geological characteristics, fluid property, formation pressure and gas production dynamic data, this research analyzes the gas reservior original gas-water distribution, the reservoir type, connectivity, deliverability evaluation and the gas seepage flow characteristics. This article researches both mechanism of water natural-flow and the production pressure decline rule of gas reservoir, by using well test and production performance data on the basis of geological characteristics research.3. The dynamic reserves is calculated by using the Pressure-drop Method, the Elasticity Two-phase Method and Improved Pressure-drop Method with consideration of well interference.This article mainly has the following main conclusions:1. The Huanglong Formation C2hl3 belongs to Tidal-flat and Barrier Beach facies, C2hl2 belongs to Barrier Beach facies, and C2hl1 belongs to Gypsum Lake and Anointed shoal facies. The dolomitization is the most common and important diagenesis during the carbonate diagenetic process of the Huanglong Formation.2. The fractures in the Shapingchang gas reservoir are mainly tectonic fracture, and the effective fracture average density is 7.41 per meter. The fractures are most small cracks, of which occurrence are most oblique and aclinic. The caves are most small caves, and the cave average density is 15.83 per meter. The reservoir represents the phenomena that middle to low porosity,the obvious difference of permeability and low water saturation. Reservoir is divided into four categories. Class III reservoirs come to the main in the whole area, and Class II mostly develop in the middle and northern gas reservoir.3. The Shapingchang gas reservoir is crack - pore type elastic gas driving low sulfur-containing dry gas reservoir dual controlled by structural and lithologic. The gas and water column simultaneous equations obtain an altitude of gas-water contact of the reservoir at -4650 meters.4. The reservoir physical properties, the fracture-hole development level ,and the connectivity of the central gas reservoir is the best, the northern is second, and the southern is the worst. Five wells have output formation water. Edge water of eastern tectonic channels through fractures of the fault belt to the Well TD90, and edge water from south invading through the miniature crack in Well YD1-1 approaches into Well TD82 and TD29, .and the formation water from the west invades along the undisconnect Fault 32 into the Well TD81.5. Using the Pressure drop method, the Elastic two-phase method and improved pressure drop method with consideration of well interference to calculate the dynamic reserves, and comprehensive evaluated dynamic reservoir in Shapingchang carboniferous gas reservoir is 323.1×108m3. |
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