Due to the fine resolution and continuity of the well log, it plays an irreplaceable role in the high frequency sequence stratigraphic division. By the adoption of the maximum entropy spectrum decomposition technology to analyze the predication error of the well log, the prediction error trend curve is obtained by further calculation. The wavelet transform technology transforms the one-dimensional depth domain logging signals into the two-dimensional depth and the scale domain logging signals. And the organic combination of the two techniques can well identify the multi-order sedimentary cycles of the stratum, so the interferences of the human factors are greatly reduced. The high frequency stratigraphic sequence division of the actual log data in Bayanhushu Sag is conducted by using this method, and the application effect is good.

In order to comprehensively evaluate the Chang-6₁ formation in Jiyuan area, we combined the cluster analysis with the gray correlative analytical method, selected the relative independent evaluation parameters from a number of parameters by hierarchic cluster analysis, and get the weight coefficient of every evaluation parameter by the gray correlative analytical method, and then obtained the comprehensive evaluation index REI. According to the value of REI, the reservoir is divided into four categories. And combined with the sedimentary facies, it is found that the high quality reservoir is in the central part of the main channel, indicating that the reservoir characteristics are closely related to the sedimentary environment. It is also shown that the combination of the cluster analysis and the gray correlative analytical method provides a new way for the reservoir evaluation, and the result has higher credibility.

During the development of the oilfield, the water flooding disturbs the primary reservoir pressure, leads to the deformation of the deep formation in the oilfield and affects the extraction ratio of oil. In order to obtain the main effect parameters of the deformation, an experiment with 3 levels for 5 parameters was conducted by Hyper-Latin square experiment based on fluid-solid coupling theory. Then, the relationships among the deformation response and the different parameters were obtained after the regression and analysis by RSM method for 33 designed experiments. The results show that the injection pressure has significant influence on the effective stress and deformation. And the properties of the reservoirs affect more on the initial stage for the effective stress, however, the later period for the normal strain. The elastic modulus of the rock mechanics properties has little effect on the effective stress, and is a significant parameter for the normal strain and subsidence.

The oil layer D in block H17 is a mid-high permeability sandstone thin oil reservoir with the gas cap and the bottom-edge water. Because of the huge thickness, the water flooding is difficult to effectively supplement the energy. The water coning is serious and the recovery degree and production rate are low. In order to realize the oil/gas gravitational differentiation, the oil production stabilization and water control, the formation pressure recovery and the development effect improvement, the research and development of the natural gas injection were carried out. Meanwhile, based on the characteristics of the reservoir, and through the combination of the laboratory experiment and the numerical simulation, we systematically optimize the gas injection position, the injection-production parameters and the production methods, put forward the pressure cone by the top injection to realize the secondary accumulation, and propose the deliverability of the oil production wells recovered by bench stoping gathering with oil ring. There’s a 8.9 % increase expected in the recovery efficiency.

The Dabei gas field, with the complex geological structure, the developed faults and fractures and the low matrix porosity and permeability, has the characteristics of high temperature and pressure, and strong heterogeneity. Under these complicated geological conditions, the reservoir characteristics are poorly described by the analytical well test with limitation. Based on the static data of the structure, the fault, the well pattern and the well logging data, the numerical well test geological model with the complex irregular boundary closed to the actual condition was established, the seepage model was established by the production data of the gas production wells, and the unstructured Voronoi mesh was generated and discrete. Meanwhile, by considering the influences of the interference from the adjacent wells, the reservoir physical property parameters revision, and the fault sealing property alteration, the numerical well test model comformed to the actual condition of the well block Dabei-102 was proposed. The result showed that, through the first research and the application of the numerical well test technologies in this block, the numerical well test analysis and the interpretation can exactly describe the feature of the pressure changes during the development of the gas reservoir in time and space, solve the problems of the communication, the fault sealing property and the interference of the inter wells in well block Dabei-102, and further deepen the understanding of the gas reservoirs. The research result helps for the production of the gas wells in well block Dabei-102.

In order to accurately predict the well capacity in the fracture of the low permeability gas reservoir, it is necessary to consider the multi-factors. The studies show that the relation between the threshold pressure gradient and the average reservoir permeability of the low permeability gas reservoir is the power function. The deformation of the media function makes the stress sensitive effect more serious, and the slippage effect makes the gas seepage resistance down and increases the well productivity. According to the conformal transformation theory, we established a prediction model of fracturing well productivity, which considered the stress sensitivity, the slippage effect and the changed threshold pressure gradient, and studied the effects on the productivity. The results showed that, with the increase of the stress sensitivity coefficient, the gas well output decreases, and the pressure of the low well bottom flow is more affected. The lower the flow pressure of the bottom hole is, the more obvious the gas well output changes with the increase of slip coefficient. The threshold pressure gradient factors greatly affect the well productivity in a certain range. Therefore, it is necessary to consider the influence of many factors on the gas well productivity in the prediction of the production capacity of the low permeability gas reservoir.

Based on the stress distribution in the zone near the well, and by the consideration of the artificial fracture induced stress, we found out the stress field around the wellbore of the fractured wells. According to the Drucker-Prage criteria, we obtained the formation stability coefficients under the different conditions. The calculation results showed that the main factors of the formation sanding are induced stress caused by the high production pressure difference instead of the gas drag. More fractures, larger induced stress and more unstable formation made the sanding easier. Meanwhile, the formation stability coefficient decreased with the increase of the permeability, and the speed of the growth overall dropped down. However, the porosity had little impact on the formation stability coefficient. As the length of the fracture increased, the stability coefficient increased as well, on the contrary, the risk of the sanding decreased. By considering the impacts of the induced stress on the stability coefficient in the process of the production, we studied the influencing factors of the sanding comprehensively, to provide the theoretical references for the sanding control design.

The further understand of the reservoir characteristics of the peripheral low permeability blocks in Daqing oilfield provides the theoretical basis for the adjustment of the development measures. Taking the block Mao-503 in Toutai oilfield as an example, and by using the equipment of the mercury injection apparatus, the X-ray energy dispersion spectrometer, the scanning electron microscope and the displacement equipment, we provide the stimulation suggestions of the improving recovery ratio by the imbibition oil recovery, according to the imbibition test and field experiment effects and based on the characters of the pore structure, mineral composition, wettability and reservoir sensitivity. The reservoir physical properties test of the block Mao-503 in Toutai oilfield shows that the main clay minerals of the reservoir rock are the illite, montmorillonite and kaolinite, the main component elements are oxygen（O）, silicon（Si） and aluminium（Al）, and the minor elements are ferrum（Fe）, magnesium（Mg）, natrium（Na）, barium（Ba） and carbon（C）. The target reservoir with the porosity between 10 % and 17 % and the permeability range of （0.40~8.2）×10 ^-3μm ² belongs to the medium porosity and ultra-low permeability sandstone reservoir. The pore throat size of the rocks is relatively small, and the sorting and connectivity are poor. Furthermore, the rocks show weak hydrophilicity, and the capillary force can be used as power in the process of the production. Meanwhile, the rocks have strong velocity sensitivity, water sensitivity and alkaline sensitivity. The indoor experiment and mineral field experiment show that the similar physical block is suitable for the imbibition oil recovery, and adding the surfactant into the water solution is good for improving the imbibition recovery and enhancing the development effects.

According to the poor water flood development effects of a typical low permeability multi-fractured block, and based on the dynamic simulation experiment system and the production technology of the fractured 3D flat cores with low permeability of the unconventional reservoir, we carried out 9 groups of physical simulation flooding experiments to research the profile control effects of the fractured reservoir with low permeability in the different injection systems and injection rounds. The result showed that the weak gel system better fitted the fractured reservoir with low permeability, and plugged the micro fractures effectively. In addition, the optimized profile control system is composed of 0.1 % concentration of 8 million molecular weight polymer, 0.1 % concentration of the profile system solution of cross linking agent, and the protection slug. It improved 31.35 % of the oil recovery by three injection rounds. Furthermore, the effects of the multi-round profile control decreased. The injected rounds should be selected reasonably according to the international oil price and the actual situation on site.

In the process of the natural gas flowing from the well head to the treatment plant, some condensate water may be produced and the transport efficiency declines due to the constant changes of the temperature and the pressure. The gathering stations of the Zizhou gas field adopt the technological process of the single station with the separated water and gas at the room temperature, the moisture vapor transport, and the hydrocarbon and dehydration took off together in the treatment plant. The separation of the water and gas at the room temperature need to determine where the condensate is by analyzing the water dew point, and ensure the reasonable running temperature under the different working conditions, so as to improve the separation efficiency of the gas station. By thewater dew point tester developed independently, the water dew point test was carried out under different pressure of the natural gas from the gas gathering stations in Zizhou gas field, that is, Zhou-1 station, Zhou-4 station and Zhou-8 station, and the index prediction model of the water dew point and pressure was established, and then, the equation of the water dew point and water content was established. The calculation results of Zhou-4 station show that the condensate water of this station mainly appears in the pipelines which connect the outside to the inside of the station in summer. The daily production of the condensate water is about 8 m ³. While in winter, the condensate water appears within the gas gathering stations and the amount of which appears in the pipelines is less than that in summer, but still exists. The pressure drop and the discharge volume changed with the date show that this calculation is more reliable. The daily water production of the gathering station by the water dew point under the pressure provide the effective measures for the pigging in field and reduce the running resistance of the pipeline.

The acidizing-water shutoff joint operation technology is an effective method to resolve the plugging, control the water injection profile, and improve the injection effect of the damaged injection wells with the strong heterogeneity. There are many factors affecting the effectiveness of the acidizing-water shutoff joint operation. Due to the complex nonlinear relations of the various factors, the traditional statistical methods is limited. To solve this problem, and based on the analysis of the effect of the acidizing-water shutoff joint operation for the water injection wells, we calculate the correlation coefficients between the factors and the increasing injection ratio by the pearson correlation coefficient method. And according to the correlation coefficient, the relative importance of each factor is determined. Then, the weight of each factor is decided by the fuzzy analytical hierarchy process. This new method is used to calculate the injection wells in the Bohai Oilfield, and the decision value is consistent with the results of the field operation. This method is reliable and simples and provide the powerful guarantee for improving the success rate of acidizing-water shutoff joint operation for injection wells.

In order to solve the problems of the distortion, damage and leakage of the casing pipes caused by the high temperature, high pressure, and the sand erosion of the thermal production wells during the exploitation of the heavy oil, a life prediction model based on the immune algorithm（IA） and the support vector machine（SVM） was built. Firstly, the IA was used to obtain the exact values of three parameters that affected the prediction accuracy of the SVM. Secondly, the life prediction model was built by taking 5 factors that affected the life of the casing as the input variables of the SVM, and the casing life as the target output. Finally, the casing wells running in Liaohe oilfield were taken as the examples to test the performance of the model. The results showed that the model could predict the casing life well with small errors and high coincidence. It provides a reference for the maintenance and repair of the casing.

The hydraulic fracturing is a major means of the coalbed methane（CBM） exploitation, and the effective channels of the methane seepage can be formed in the coal seams by this means. The stimulated reservoir volume（SRV） can not only help the coal seams form the seepage channels, but also increase the desorption-diffusion areas of the methane and improve the production of the single well by formed the complicated fractures. The brittleness index is one of the key parameters for evaluating the SRV implement, therefore, based on the stress-strain curves of the coal and shale, it is analyzed with the help of the strain-energy density. The higher the brittleness index of the shale is, the lower the strain-energy density will be. Based on the calculation method of the brittleness index of the shale, the calculation method of the coal brittleness index that combines with the strain-energy density and minimum energy principle is put forward, and the modified brittleness index of the coal is obtained, which can be used for the characterization of the coal brittle failure and evaluation of the fracture formation after fracturing. Finally, the analysis of the calculation results and data of 6 fracturing wells, indicates that the strong correlation between the coal brittleness index and stimulated volume, which means that the higher the brittleness index is, the larger the stimulated volume of unit fracturing fluid in the coal seams will be. This method can be applied to design the SRV of the coal seams and guide the exploitation of CBM.

At present, the optimizing evaluation indexes of the existing favorable target areas of shale gas, is not comprehensive, and the evaluation methods are not taking full advantage of the uncertain information indexes. Therefore, the enrichment, accumulate, and storage of the shale gas, and the surface condition of the exploration and development are analyzed. On this base, by combining the successful exploring experience of the shale gas aboard with the characteristics of the domestic marine shale gas accumulation, we selected 13 comprehensive evaluation indexes, including the netshale thickness and the organic carbon content of the shale gas favorable target areas, and proposed the corresponding classified evaluation standards. Because of the thick shale gas reservoir, the heterogeneity and the lack of the geological awareness of the evaluation parameters, the interval value of the evaluation indexes replaced the average value of the uncertain information evaluation index, and the fuzzy similarity evaluation method based on the fuzzy similar theory was established. The calculation results show that, compared with the comprehensive information superposition method, this method is more reasonable, effective, simple and useful. It can provide reliable evidences for the optimal of the favorable target areas of shale gas.

The well Longye-1HF is one of the key exploration wells locating in Wulong syncline structure of southeast Sichuan. Its target stratum is Longmaxi formation of lower silurian. Compared with the fracturing of the shall wells in anticline of Jiaoshiba area in the city called Fuling, the well Longye-1HF have the characteristics of high fracture pressure, high extension pressure and difficult sand adding. According to the geologic condition of Wulong area, Longmaxi formation has good lamellation development and high quartz content. However, the ground stress difference coefficients are small. In order to stimulate the transform volume of the reservoir, the research were conducted on the fracturing technology of the atmospheric shale horizontal wells in Wulong. Through the pumping bridge plug and perforating technology, we selects a mixed fracturing fluid of low damage slick-water and activity glue, and optimizes the construction displacement and fracture parameters. The fracturing construction is divided into 17 segments, and after fracturing, it achieves 6.2×10 ⁴ m ³/d industrial gas. The results verify the gas bearing properties of the middle-shallow shale reservoir in Wulong block, and the production capacity achieves the breakthrough.