Pudjo Sukarno

An Investigation on Gas Lift Performance Curve in an Oil-Producing Well

The main objective in oil production system using gas lift technique is to obtain the optimum gas injection rate which yields the maximum oil production rate. Relationship between gas injection rate and oil production rate is described by a continuous gas lift performance curve (GLPC). Obtaining the optimum gas injection rate is important because excessive gas injection will reduce production rate, and also increase the operation cost. In this paper, we discuss a mathematical model for gas lift technique and the characteristics of the GLPC for a production well, for which one phase (liquid) is flowing in the reservoir, and two phases (liquid and gas) in the tubing. It is shown that in certain physical condition the GLPC exists and is unique. Numerical computations indicate unimodal properties of the GLPC. It is also constructed here a numerical scheme based on genetic algorithm to compute the optimum oil production.

Optimization of Gas Injection Allocation in a Dual Gas Lift Well System

1. Abstract Optimization problem for oil production in a multi gas lift wells system is discussed. The main problem is to identify allocation of gas injection for each well to obtain maximum total oil production. The gas injection rate is constrained by a maximum limit. Oil production rate is a nonlinear function of gas injection rate, which is unknown explicitly. In existing approaches, the nonlinear function is estimated from empirical or numerical simulation data, by curve fltting using regression method, or estimated by piecewise linear function. We developed here, a mathematical model for gas lift well system, where the ∞uid ∞ow in reservoir and pipes consists of liquid and gas, so the conditions represent two phase ∞ow phenomena. Relationship between gas injection and oil production is given implicitly from the model. We have also developed a computation scheme to solve the optimization problem. Considering complexity of the problem, computation scheme is developed based on genetic algorithms. Our results show quite good estimation for optimum solution. The approach also gives better quality prediction over existing approach, since all computation results come from the model, not from regression or interpolation. 2. Keywords: Gas Lift, Gas Lift Performance Curve, Constrained Optimization, Genetic Algorithm.

Inflow Performance Relationship For Perforated Wells Producing From Solution Gas Drive Reservoir

The IPR curve equations, which are available today, are developed for an open hole wells. In the application of Nodal System Analysis in perforated wells, an accurate calculation of pressure loss in the perforation is very important. Nowadays, the equation which is widely used is Blount, Jones and Glaze) equation, to estimate pressure loss across perforation. This equation is derived for single phase flow, either oil or gas, therefore it is not suitable for two-phase production wells. In this paper, an IPR curve equation for perforated wells, producing from solution gas drive reservoir, is introduced. The equation has been developed using two phase single well simulator combine to two phase flow in perforation equation, derived by Perez & Kelkar). A wide ranges of reservoir rock and fluid properties and perforation geometry are used to developed the equation statistically.

Modeling and simulation performance of sucker rod beam pump

Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

A robust method for determining the optimum horizontal well direction and length for a petroleum field development using genetic algorithm

Locating a horizontal well to maximize a gas field production requires not only a right direction but also horizontal segment length. This is due to the longest segment does not necessarily give the maximum gas production, and each direction has its own optimum segment length. Currently, this problem is solved through a trial and error method. This method requires significant efforts and time to find the best location in order to provide a good reservoir model. In this study, a new construction of an optimization problem for optimizing gas production is proposed. Genetic Algorithm is applied to avoid the trial and error procedure. A set of two consecutive objective functions is constructed, i.e., one which is based on the quality of basic reservoir rock properties resulted from summing of all the grids of objective function values in a chosen direction, and the second one which is derived from a curve fitting cubic spline function of the cumulative gas production at a plateau time period with respect to t...

Heat loss model for flow assurance in a deep water riser

The study is intended to investigate the heat loss phenomenon of oil flow in a riser. This heat loss happens due to the difference between the oil temperature in a riser and the surrounding sea water temperature. It causes the formation of wax that may disturb the flow. Heat loss can be reduced by setting up an insulator in a riser or by selecting appropriate pipeline specifications. It is necessary to determine the possible locations and specifications of insulator and pipeline. A mathematical model is formulated by considering the oil temperature and its flow velocity. Assuming that the density variation is small, the fluid behaves as an incompressible fluid. Furthermore, numerical solutions with finite difference methods are presented with some hypothetical data to give an overview of how the system works. Two surrounding conditions are taken into account, i.e. with and without sea current. From the simulation, the location of wax formation can be predicted. At a certain depth region of sea, where the sea current is present, a greater heat loss take place in which wax may be formed immediately. To overcome the formation of wax, we can control the parameters such as conductivity and wall thickness of pipe.The study is intended to investigate the heat loss phenomenon of oil flow in a riser. This heat loss happens due to the difference between the oil temperature in a riser and the surrounding sea water temperature. It causes the formation of wax that may disturb the flow. Heat loss can be reduced by setting up an insulator in a riser or by selecting appropriate pipeline specifications. It is necessary to determine the possible locations and specifications of insulator and pipeline. A mathematical model is formulated by considering the oil temperature and its flow velocity. Assuming that the density variation is small, the fluid behaves as an incompressible fluid. Furthermore, numerical solutions with finite difference methods are presented with some hypothetical data to give an overview of how the system works. Two surrounding conditions are taken into account, i.e. with and without sea current. From the simulation, the location of wax formation can be predicted. At a certain depth region of sea, where the ...