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Estimation of the New Gas-cap to the Performance of the Reservoir of the Oil Field Libwa, Offshore of the Democratic Republic of Congo
Joel Kabesa Kilungu,
Dominique Wetshondo Osomba,
El-Richard Molodi Empi,
Shams Diambu Mbudi,
Romulus Mawa Tuzingila,
Link Bukasa Muamba,
Junior Mbambo Bokitshi
Issue:
Volume 7, Issue 6, November 2019
Pages:
109-117
Received:
16 September 2019
Accepted:
29 October 2019
Published:
20 November 2019
Abstract: The quantity of hydrocarbons initially in place and the technique of exploitation employed in the reservoir determine the period of an oilfield. But the quantity of hydrocarbons in a reservoir defines as a preliminary the type of mechanism drainage which governs the pressure of the oilfield. And this pressure is the key parameter of the oil production. Thus, the mechanism of drainage is a motive element which shows the performance of an oil reservoir during the production. During the oil production in the Upper Pinda reservoir of the Libwa field, the mechanism of drainage used was that of gases in solution. It was noticed that during the production, an abrupt drop of the pressure of 2670 psia with 1567 psia and a cumulated production of oil of 239805 Stb at the end of the year 2018. However, certain studies undertaken in this field revealed the presence of a gas cap which could compensate for the mechanism with dissolved gas but which seemed to be ineffective during the drop pressure. Thus through our study, we put in evidence the existing quantity of gas in the primary gas cap which are worth 1.09414 MMscf under the basic conditions and with the factor of the primary gas cap (m) with 0.0018 who is scarcely and the new gas cap which is created starting from the addition of a quantity of dissolved gas released during the production of which the quantity of this gas is estimated at 1.86329 MMscf under the basic conditions and, the new factor of the gas cap (m) is worth 0.0059 and the value of this new factor of the gas cap (m) is almost null too. Taking into consideration these result, it is shown that this new gas cap will be always ineffective with the performance of the reservoir. On this it is necessary that the factor of the gas cap reaches a value at least equal to 10 to completely replace the mechanism with gas dissolved in the Upper Pinda reservoir in the Libwa field.
Abstract: The quantity of hydrocarbons initially in place and the technique of exploitation employed in the reservoir determine the period of an oilfield. But the quantity of hydrocarbons in a reservoir defines as a preliminary the type of mechanism drainage which governs the pressure of the oilfield. And this pressure is the key parameter of the oil product...
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Analysis of Factors Affecting Bottom Hole Pressure in Tight Gas Reservoir
Issue:
Volume 7, Issue 6, November 2019
Pages:
118-124
Received:
11 July 2019
Accepted:
20 August 2019
Published:
25 November 2019
Abstract: In order to solve the problem of low accuracy of bottom hole pressure in tight gas reservoir, this paper presents a new way to analyze the bottom hole pressure. By combining literature research and starting from nonlinear motion equations, the model of bottom hole pressure was established through using various mathematical methods such as separation variable method, identity transformation method and differential discrete method. This paper presents a high-precision and high-efficiency method for solving bottom hole pressure in tight gas reservoirs, and a dynamic calculation method for permeability and conductivity is given. Through the sensitivity analysis of the influencing factors of dimensionless pressure and pressure derivative, it is concluded that the larger the power law index is, the larger the warpage of the dimensionless pressure and pressure derivative curve is. The larger the skin coefficient and the wellbore storage coefficient is, the earlier the fluid enters into the quasi-steady-state seepage. When the tight gas reservoir contains closed edges, the resolution points of the dimensionless pressure and pressure derivative curves are obvious with crossing. On the contrary, when the tight gas reservoir contains the constant pressure boundary, the resolution points of the dimensionless pressure and pressure derivative curves are not obvious without crossing.
Abstract: In order to solve the problem of low accuracy of bottom hole pressure in tight gas reservoir, this paper presents a new way to analyze the bottom hole pressure. By combining literature research and starting from nonlinear motion equations, the model of bottom hole pressure was established through using various mathematical methods such as separatio...
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Study on a New Method for Calculating Water Saturation
Yang Kebing,
Xie Li,
Zhang Lei,
Li Jun,
Cao Chengcheng
Issue:
Volume 7, Issue 6, November 2019
Pages:
125-129
Received:
20 October 2019
Accepted:
15 November 2019
Published:
25 November 2019
Abstract: In order to improve the identification and evaluation accuracy of low resistivity oil layer and complex pore structure oil layer, and to avoid the interpretation error caused by the traditional evaluation mode of “high resistivity is oil layer and low resistivity is water layer”, the method of calculating water saturation by radial resistivity ratio was studied. The results show that the radial resistivity ratio can be used to calculate the reservoir water saturation for completely invaded formation, which can be deduced according to archie formula. The new formula does not evaluate oil and water layers based on high or low of resistivity, but can be used to evaluate low resistivity oil and high resistivity water layers. After testing core experimental data, The new formula can effectively calculate the water saturation and meet the requirement of using. After practical application of data, The average absolute error of the calculated water saturation is 3.55%, which conforms to the industry standard. This method is helpful to improve the coincidence rate of logging interpretation, and is worth popularizing.
Abstract: In order to improve the identification and evaluation accuracy of low resistivity oil layer and complex pore structure oil layer, and to avoid the interpretation error caused by the traditional evaluation mode of “high resistivity is oil layer and low resistivity is water layer”, the method of calculating water saturation by radial resistivity rati...
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Simulation of Acid–rock Heterogeneous Flow Reaction Based on the Lattice Boltzmann Method
Bo Ning,
Zhonghua Chen,
Ninghai Fu,
Xin Zhao
Issue:
Volume 7, Issue 6, November 2019
Pages:
130-143
Received:
3 November 2019
Accepted:
29 November 2019
Published:
13 December 2019
Abstract: Matrix acidizing is an essential strategy to maintain or increase the productivity or injectivity of hydrocarbon wells. However, for sandstone reservoirs, the heterogeneous flow reaction mechanism of acid–rock in porous media is very complex because of their complex mineral and chemical compositions. It is often difficult to match real formation conditions by experimental simulation. Also, traditional numerical simulation methods have the disadvantages of complex boundary processing and low computational efficiency. In this study, the lattice Boltzmann method (LBM) was used to establish the heterogeneous flow reaction model of acid–rock from a new perspective, which was solved by MATLAB to obtain the distribution of temperature, concentration of various substances, porosity, and permeability. The simulation results indicate that with increases in injection time and injection speed, the temperature and mass transfer distance of the acid will also increase. Changing the injection time had a more obvious influence on the transfer of temperature and mass than did changing the injection speed. The increasing rates of porosity and permeability in the middle of the flow channel were the highest. The fast-reaction mineral content, hydrofluoric acid injection concentration, and acid injection time had a great influence on the acidizing effect, whereas the slow-reaction mineral content, acid injection temperature, and injection speed had little influence on the acidizing effect. The results suggest that to improve the acidizing effect, priority should be given to improve the HF concentration and acid dose. It will be important for further guiding the optimization of acidizing process design parameters.
Abstract: Matrix acidizing is an essential strategy to maintain or increase the productivity or injectivity of hydrocarbon wells. However, for sandstone reservoirs, the heterogeneous flow reaction mechanism of acid–rock in porous media is very complex because of their complex mineral and chemical compositions. It is often difficult to match real formation co...
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