Advanced Materials Research Vols. 524-527

Abstract: Reservoir X is a fractured-porous dual-media reservoir. According to the geological conditions and exploration and development statuses of reservoir X, this paper designs a long-core experiment and then carries it on. As a result, the diffe_{Subscript text}rent enhance displacement efficiency effects under different driving methods (water flooding, gas flooding, WAG, pulsed gas injection, gas slug flooding) and different driving media (flue gas, CO₂) are obtained. The results show that among all those driving methods, water alternating CO₂ injection (WAG) reaches the best effect. WAG has an injection rate of 0.8HCPV and enhances displacement efficiency by 26.93% on the basis of water flooding. The injection rate of gas slug/water flooding after CO₂ slug flooding is 0.3HCPV and these two methods have similar good results, 13.66% and 13.95% respectively. So considering the economic factor, we draw a conclusion that water flooding after CO₂ slug flooding is the optimum choice.

Abstract: Aiming at the deficiencies of tubing-conveyed oriented perforating technology for horizontal well, a pumping perforation technology in horizontal well has been developed. Pumping perforation technology process is a perforation process transferring the perforating gun string into perforation section of the horizontal well with pumping fluid, and then completing the perforation while perforating bullets exploding after powering on, and finally towing back the perforating gun to the ground with cable. It is of the advantages such as simple perforation column, simple and convenient process and the shorter operating time. Perforating gun string is acted on by the impact, gravity and buoyancy of pumping liquid during moving in the horizontal section. Based on the theory of metal friction and the hydraulics principles, the calculation model of the critical injection rate (namely pumping displacement ) in the horizontal section is established by considering the effect of the composition of the gun string, buoyancy, friction coefficient, heavy guns, gun ramps, pumping fluid density, and calculated the impact of impact, effects of assembly components of gun string, pumping-fluid buoyancy, frictional coefficient, weight of gun, angle of gun-string, pumping-fluid density and computing method of impacting force. Field applications show that the calculation model established can meet the construction needs.

Abstract: The theories of rock and soil mechanics and nonlinear finite element method were introduced to casing damage analysis, the physical models of casing damage were established, the relation between the water injection pressure and strata dislocation was investigated, also the influence of fault was considered. The results based on the nonlinear finite element method show that the water injection pressure is the direct cause of strata dislocation. The fault has significant influence to strata dislocation. When the fault exists, even the natural pressure of water injection may cause considerable local strata dislocation. The high pressure of water injection will not produce strata dislocation at the absence of faults. The casing damage near the fault is probably caused by strata dislocation, but the casing damage far from the fault may be considered causing by other factors. The present method offers theoretical reference for taking measures scientifically to prevent and control casing damage, and also offers a new idea for casing damage analysis.

Abstract: Through expounding the function of Sort and Subtotal of Microsoft Office Excel and analyzing its application in oilfield data processing, this paper provides a convenient method of oilfield data Excel-processing for oil-workers in order to improve work efficiency.

Abstract: Under pressure and activity difference between drilling mud and poro fluid, the degredation of mudstone mechanic features will change with the saturation time. It reveals that the reduction of the mudstone strength parameter and the decrease of the elastic modulus are the results of hydration stress development after the mudstone hydration. This paper proposed that the damage of soft mudstone is caused by the hydration stress development. After introduced the internal damage variable in the linear constitutive equations of viscoelastic materials, the approximate equation about the changing rate of the internal damage variables and the changing rate of the hydration stress can be got.

Abstract: The development of gas-oil reservoir with condensate gas is more difficult than pure gas reservoir or oil reservoir. This article gives the example of G oil reservoir the development of gas cap and oil rim. According to the characteristic of the oil developing and the results of numerical simulation, the rules for oil and gas developing and developing time have been defined, by which the recoveries of gas, oil, and condensate oil will reach a significantly high level.

Abstract: In order to enhance the oil recovery of low permeable oil-field, this paper uses the Eclipse software to establish the component numerical simulator of formation crude, analyzes the factors that influence on CO₂ flooding, such as permeability, the crude oil relative density, the inlayer heterogeneity, interlamination heterogeneity, intrastratal cross flow channel and so on. The results show that along with the increasing of the permeability, the degree of reserve recovery of CO₂ flooding enlarged, and with the increasing relative density of the crude oil, the degree of reserve recovery of CO₂ flooding decreased. The stronger of the in layer heterogeneity and the interlamination heterogeneity, and the higher of the permeability of the cross flow channel is, the lower level of CO₂ flooding degree of reserve recovery it tends to be. The light reservoir which with poor development in vertical permeability or in the thin oil layers should be selected to use the CO₂ flooding, in order to guarantee a better development effect on the low permeable oil-field.

Abstract: During the process of drilling, overflow happens when the waterhole blocks, drilling tool breaks off and drops into the well, or empty hole occurs after hoisting completed. In course of the workover operation, overflow happens while oil tube fracturing, blocking up, and occurring empty well or can’t flow. As it is difficult to establish effective fluid cycling for such type of well when overflow occurs, conventional killing well method cannot handle the problem of overflow for the well in special operating conditions. The so-called special operating conditions well have intact well head control equipment, but unable establish cycling after the overflow well shut in. The paper is aimed at finding out the non-routine well control procedure to deal with the overflow of the well in special operating conditions. Study the well killing technology in four situations. The situation included the well is full of natural gas, lower of the well is liquid column and upper of the well is natural gas, the wellbore blocks and unable establish cycling for containing liquid column, besides the wellbore holds fish where the fish is intact and doesn’t block the wellbore, the fish blocks the wellbore or the fish is breakup and blocks the wellbore. Discuss the principles, steps, calculation procedure and formulas of killing well in volumetric control mode. The result is applied in one of the non-conventional wells’ workover operation in the eastern of Sichuan. This paper simulates the calculation of killing well and reveals the killing well curves and form design.

Abstract: For the trends of global climate warming, it is great important to implement the Carbon capture and storage (CCS) technology. This paper describes the numerical simulation of CO₂ displacement enhanced oil recovery (EOR) in M reservoir. The M reservoir is an extra-thick buried hill fractured reservoir, which use overlap alternative horizontal well pattern to produce. Considering the time-varying effects of fracture’s porosity and permeability parameters, combining the develop dynamic and the diversification of physical property parameters of fractured formation, use the dual porosity dual permeability model and the three-dimensional components simulator to simulate the develop process. By CO₂ WAG orthogonal experiment design, can simulate and predict the development effect of fractured buried hill reservoir affected by factors such as: different production and injection well pattern, injection intensity, gas water slug ratio, alternating cycle and so on. The results show that in the process of CO₂ WAG can significantly reduce the risk of gas breakthrough by overlap alternative horizontal well pattern, and reduce the negative impact by fracture properties, also can improve EOR and CO₂ sequestration effectively. On this basis, this paper evaluates the suitability of WAG development methods to fractured buried hill reservoir with overlap alternative horizontal well pattern, also optimizes the reasonable development plan for M reservoir.

Abstract: In exploration of coalbed methane, the release and accumulation of absorbed gas driven by underground water is equal to existence of high-resistivity conductor. Application of numerical modeling conducted with finite difference to analyze anomaly sounding corresponding to underground high-resistivity conductor in borehole-ground DC method, and research of casing effect for DC method combining with physical modeling, may attribute to development of borehole-ground DC method which is capable for exploration of coalbed methane.