Fracturing technology is one of the most efficient ways to productivity evaluation, and the key of fracturing technology is how to describe rock mechanical behaviors to which S-wave slowness is an important parameter. According to the complexities of low porosity and low permeability of Pucheng oilfield, we designed and obtained the experimental scheme for measuring the velocities of P-wave and S-wave. The samples are focus on dry sample and rock with water saturation 100%, 80%, 60% and 40% respectively, under two conditions at normal temperature with 5MPa and with formation pressure at 90°C. By conducting triaxial test, the velocities of P-wave and S-wave under different temperatures and different pressures were obtained. On the analysis of 26 groups of data, the results showed that on the formation condition, S-wave slowness value varied linearly with water saturation, and S-wave slowness was also linear to P-wave slowness at different water saturation. Oil-bearing layer and water layer models were created separately, to compute S-wave through P-wave based on linear interpolation. We validated the new approach with an example from real array acoustic log data of Pushen 18 well. The results demonstrated the advantages of this method over empirical equation proposed by Entwisle’s and Dreiser Company. The relative error from them compared with log data are more than 10% whereas that of our method is 4.2%.

The freshwater mud invasion caused low resistivity contrast of oil and water zones in well block YD, then the reservoir fluid is very difficult to identify. By simulation study, the authors find freshwater mud invasion made the oil reservoir resistivity increase rate R/Ro from 3.8~6.8 to 1.5~2.5, and made a 65% reduction in the reservoir resistivity. But the water layer resistivity rise by 50%. That further reducing the contrast of the reservoir resistivity. Logging fluid identification rate of the reservoir is less than 74%. So the authors partition the well block YD, calculate a mixture resistivity of formation water after freshwater mud invasion, calculate true formation resistivity, then use resistivity increases rate and reservoir quality factor to establish reservoir recognition charts. This method rise the coincidence rate of 17 %.We use the method to deal with 49 wells in well block YD. The results raise the rate of approximately 10% than the original interpretation. It is a powerful direction for low resistivity well log interpretation.

At present, the most advanced remaining oil saturation logging technologies are RPM RST RMT PNN PND in domestic and outside. But these have only been made some correction of porosity, lithology, borehole conditions, formation water salinity, oil density. So they are not suitable for application in the offshore heavy oil reservoirs of gravel pack. The writer has designed a volumetric model of considering gravel pack, casing size, wellhole liquid and so on. And some correction formulas are deduced with single factor and multiple factors by combining this volume model. While the author use these formulas to establish some theoretical charts. In the case of that the porosity is 0.3, the author analyzes the C/O value change rule with the same oil saturation in sandstone strata. When the gravel packing volume of 0.1, the C/O value decreases about 0.15. When casing diameter increases from 6inches to 7inches, the C/O value increases about 0.2. When the casing diameter is 6inches, make the clay content, gravel content, and calcium content for 0.1, the C/O value increases about 0.6. After making the gravel pack and other influencing factors correction, contrast RPM data interpretation results and PLT data interpretation results. It is found that the results of remaining oil explain accuracy is improved 10% or more. These methods provide a new theoretical basis for the offshore heavy oil reservoir in the fine interpretation of RPM data.

According to the needs of exploration and development, the main purpose of the Fulongquan region layer (Quanyiduan) to explain the fine structure and a favorable objective evaluation. Fine structural interpretation based on high-resolution, high fidelity and high signal to noise ratio of seismic data, the use of Landmark Interaction software layer on the purpose well - seismic calibration, determine the target layer of seismic reflection and seismic wave group phase characteristics of other wells in the area of information work carried out under the lateral auxiliary tracking method with variable velocity mapping layers of the structure plan aims to implement the target zone traps. In the structural interpretation based on the use of coherent technology and time slice for fault identification, combined with relevant geological data on the target layer of oil a comprehensive evaluation, selection of a good oil and gas traps, providing for the exploration and development goals.