The Evaluation Of Deep Source Rocks And Prediction Of Favorable Areas In The Mid-west Fault Depression , Songliao Southern Basin

With the rapide development of the deep gas exploration these years, the volcanic rocks and clastic reservoirs in the south of the SongLiao Basin have got a great breakthrough, showing the bright prospects of the deep gas exploration in the south of the SongLiao Basin. At the same time, gas reservoirs with high CO2 or pure CO2 gas are often found while looking for pure hydrocarbons reservoirs, so far, how the potential of the deep source rocks is on earth ? How much hydrocarbon gas resources there is? This has become the region's problems in the deep gas exploration which remains to be solved. This passage gives remarks on the deep source rocks in the YingTai rift and Changling depression in the south of the SongLiao Basin based on this problem, then the time of the accumulation of hydrocarbon and the comparition of gas source is dicussed, and we also give the forecast of beneficial areas and the selection of the targeting wells considering the main controlling factors of gas accumulation. It means great guiding significance to deep gas exploration in the next step .Estimate the abundance, type and maturity of the source rock using the measured analysis test data, and describe the uneven value of the source rock according to the improved logging geochemical valuation methods, eliminating the evaluation error the limited measured data caused. The improvedΔlogR logging geochemical method mainly use the computer to automatically fit the the best combination relationship between time difference of acoustic wave and resistivity,making the measured TOCand the calculated TOC get the best correlation so that the calculated TOC can represent the actual source rock abundance better.Thermal history recovery is the foundation of quantify evaluation of hydrocarbon source rock, this study recovers the thermal history of Yingtai fault magmatism invasive area (Long 1 deep well area),based on routine Thermal history recovery of the Yingtai and Changling rift, and comprehensive consideration of the thermal effect of volcanic rocks.The hydrocarbon bisect in the studied area is seted up mainly according to the results of the thermal simulation experiment in the the aspect of quantitative evaluation of source rocks. Based on this, we do the the recovery of the original organic carbon and hydrocarbon potential, and calculate the amount of hydrocarbon generation and expulsion using the method of chemical dynamics combined with Monte Carlo. Firstly, analyse Markov probability distribution of the measured TOC and HI and random sample with the Monte Carlo method according to the probability distribution characteristicsof paraters, and then do the simulation calculation of the amount of hydrocarbon generation using these sample data, after several times of sampling simulation, finding the law of probability distribution of hydrocarbon generation amount and obtaining the hydrocarbon generation amountn under different probability risk.As for the identification of ways of natural gas accumulation and accumulation period, we mainly study from the two aspects of the perspective of carbon isotope fractionation and fluid inclusions. Study the evolution of methane carbon isotope trend using carbon isotope dynamics combined with chemical dynamics. To determine the hydrocarbon gas into the reservoir model and the accumulation period in the study area, also determine the natural gas accumulation period.using homogenization temperature of fluid inclusion and the results of thermal history recovery.Using the components of natural gas, isotopic and light hydrocarbon composition to analysis the origin of natural gas, elaborate the reason of the reverse of the isotope, and determine the origin of natural gas. The maturation of natural gas and light hydrocarbon fingerprint are used to be Gas source correlation, clear the sources of natural gas in the region.Volcanic rock is the mainly reservoir space of the deep strata natural gas,this article mainly embarks from the diagenesis, the influence of the diagenesis of volcanic rocks and it's influence to the reservoir. Analyzed and described reservoir spaces type of the volcanic reservoir, and cleared the superiority of the deep volcanic reservoir. in the study area.Considering such factors as state of the Source rock,reservoir,cap rock,tectonic activity of casualties , analyze main control factors for hydrocarbon accumulation of the sample well ,made prediction of favorable areas and the selected objective target well position. The results show that the area nearby the hydrocarbon source rock or volcanic rock inside the source rock is the place where hydrocarbon gas easily to get together, because the gas in the area where far away from the hydrocarbon source rock has small molecule easily to diffuse and hardly to lateral move for a long distance,it is difficult to generate hydrocarbon gas reservoir.