Advanced Materials Research Vols. 962-965

Abstract: The major method for developing heave oil is steam soak/steam injection technology. During the steam injection, inner zone radius increased; while during shut in, inner zone radius decreased, in order to find the effect of removable inner zone radius on well testing analysis, we developed a new mathematical model with two zones and the inner zone radius is removable with time. The well bore storage and skin effect are considered. The well bore pressure response solution was obtained by using Laplace transform; typical curves were made by using Stehfest Laplace numerical inversion algorithm. The feature of the typical curves were analyzed and compared with those base on the conventional model. Based on this model, the movement feature of heating front during steam injection /soak can be evaluated.

Abstract: Oilfield water is a complex chemical system whose classification is an important proposition of oilfield water geochemistry. This paper makes some analysis and discussion according to the V.A.SuLin’s theory using the data of some oilfield water samples. The result shows that the theory has some limitations in the classification of oilfield water and should be combined with the actual situation of oilfield development.

Abstract: There were many ways for the identification of 3D seismic data of fracture system,and the traditional manual fracture identification was time consuming.The automatic ant tracking technique for fractures based on ant colony optimization (ACO) is a new method developed in recent years.It displays clearly the distribution of fracture systems and faults.Compared to manual interpretation which only identifys a small amount of very obvious fractures and faults,the new method is more objective,and more clear, accurate and intuitive.This paper proposed the research idea of taking Tahe oilfield 4th block as an example,to identify fractures and to set up the fracture model.The model can display 3D structure shape of the reservoir and have achieved good results.

Abstract: Fracturing as a method to stimulate shallow, hard rock oil wells dates back to the 1860s. The first hydraulic fracturing technology was applied in the US states of Pennsylvania, New York, Kentucky in 1947. Hydraulic fracture was formed by pumping the fracturing fluid into the wellbore at a sufficient rate to increase downhole pressure to exceed that of the pressure gradient of the rock. In this paper, a few key techniques including hydraulic fracturing for the development of oil and gas resources were introduced. It has become a common technique to enhance the production of low-permeability formations, especially unconventional reservoirs such as tight sands, coal beds, and deep shales. Therefore hydraulic fracturing has been considered as “killer mace” for development of unconventional hydrocarbon resources in the world.

Abstract: Pressure monitoring is an important means to reflect the running status of the natural gas desulphurization process. By using the data mining technology, the interaction relationships between the pressure and other monitoring parameters are analyzed in this paper. A pressure trend prediction model is established to show the pressure status in the natural gas desulfurization process. Firstly, the theory of Principal Component Analysis (PCA) is used to reduce the dimensions of measured data from traditional Supervisory Control and Data Acquisition (SCADA) system. Secondly the principal components are taken as input data into the pressure trend prediction model based on multiple regression theory of Support Vector Regression (SVR). Finally the accuracy and the generalization ability of the model are tested by the measured data obtained from SCADA system. Compared with other prediction models, pressure trend prediction model based on PCA and SVR gets smaller MSE and higher correlation. The pressure trend prediction model gets better generalization ability and stronger robustness, and is an effective complement to SCADA system in the natural gas desulphurization process.

Abstract: Because of the gas slippage, the testing methods of stress sensitivity for gas reservoir should be different from that for oil reservoir. This text adopts the method that imposing back pressure on the outlet of testing core to weaken the gas slippage effect and tests the stress sensitivity of low permeability gas reservoirs, then analyzes the influence of permeability and water saturation on stress sensitivity. The results show that: low permeable and water-bearing gas reservoirs have strong stress sensitivity; the testing permeability has the power function relationship with net stress, compared to the exponential function, the fitting correlation coefficient is larger and more suited to the actual; the lower the permeability is and the higher water saturation is, the stronger the stress sensitivity is. The production of gas well is affected when considering the stress sensitivity, so the pressure dropping rate should be reasonable when low permeable gas reservoirs are developed. The results provide theoretical references for analyzing the well production and numerical simulation.

Abstract: At present, Most of the studies on source rocks is above the effective source rock identification and quality evaluation. But the spatial distribution of the high quality source rocks do not necessarily reflect the position of the layer. So, logging evaluation of the relationship between source rock and layer distributed in a region is necessary. In this paper 70 cores have selected from 4 wells in the first period of Qingshankou (q¹), Songliao Basin, then get the experimental TOC value after core analysis. On the basis of source rock geochemical analysis, the author estimated the source rock TOC value with the ∆lgR method. As the distribution of high quality source rocks are clarified,the author draw a conclusion by researching on the relationship between the distribution of source rocks and layers which based on the "Source Control Theory" theory. Finally, it is found that the quality of the source rocks and layer distribution match well in both horizontal and vertical in this paper. This discovery is important for layer prediction and researches.

Abstract: CO₂ injection into oil reservoirs can both enhance oil recovery and realize CO₂ geological sequestration. The gas diffusion coefficient of CO₂ in oil and water is a very important factor for EOR. This paper developed a simple experimental technique for measuring the CO₂ diffusion coefficient in heavy oil. In this paper, we find the relationship between initial pressure and diffusion coefficient and equilibrium pressure at the same temperature.

Abstract: In this paper, the influence of mahogany sulfonate and nonionic surfactant to oil displacement system viscosity is evaluated. The effect of the two kinds of surfactants was compared by oil displacement test, the results showed that nonionic surfactant not only had no effect on oil displacement system viscosity, but also had a good oil displacement effect.

Abstract: The research and application of LH-I liquid bridge plug - a kind of wellbore working fluid for plugging the lower formations are introduced in detail in the paper. The plug is reliable and easy to operate, eliminating the running and pulling of strings in mechanical plugging and requiring no fishing operations. It can be used for isolating and plugging the lower formations inside the wellbore, especially for wells with small barrier layers, hard to set wells, initial sand control wells, and wells completed with 177.8mm (7〞) casing and 127mm (5〞) tail pipe, in which mechanical packers and mechanical bridge plugs can not be used.