The design of an optimal sand control method and production management is a complex problem due to the simultaneous influence of various factors. Typical effective variables for choosing an optimum sand control method include geological, technical, economical, and expert’s experience on similar projects. Some technical factors, which affect the optimum method, are the type of exclusion, gravel size of gravel pack and pre-packed screen, slot width and liner slot length, and productivity index reduction. The situation could be more complicated due to the uncertainty associated with various contributing factors. Therefore, it is crucial to develop a novel approach in order to select the best sand control method with a maximum level of confidence. In this study, to select an optimal sand control method, Multi Criteria Decision Matrix (MCDM) techniques including Analytic Hierarchy Process (AHP), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and, ELimination and Choice Expressing REality (ELECTRE) are used. To simulate fluid flow, an integrated model of reservoir, well, and surface facility is used based on actual oil field data collected from the south of Iran. Then, Design of Experiment (DOE) and Response Surface Methodology (RSM) are applied to optimize the controllable variables of the best selected sand control method by MCDM. Finally, Monte Carlo Simulation (MCS) is applied to perform sensitivity and uncertainty analysis in order to determine the crucial factors that control net present value (NPV). The results show that the best sand control method based on AHP, TOPSIS, and ELECTRE is the slotted liner. After that, three different methods of pre-packed, gravel pack, and wire wrapped are respectively the most efficient sand control methods based on an average score of all the MCDM techniques. The results also indicate that although the pre-packed screen has the highest NPV, it is not the best sand control method due to the influence of other efficient criteria. The result of sensitivity analysis using MCS in terms of contribution to total variance shows that slot width, slot density, and slot height controls 60.5%, 38.8%, and 0.7% of the NPV variation within the range of factors, respectively.

Introduction

Methods of sand control were first utilized in water wells and then were later applied in oil and gas wells. There are several methods of sand control, which used to control the sand production, include mechanical and chemical methods. Mechanical methods involve the use of screens to retain the formation sand (with or without gravel) or use of gravel to hold formation sand (with or without a screen to retain the gravel) including gravel pack, pre-packed screen, slotted liner, and wire wrapped. Chemical methods employ a liquid resin which is injected from a wellbore into the unconsolidated rock surrounding the well. Chemical methods involve in-situ sand consolidation techniques and resin-coated gravel pack. The design of an optimum sand control is a complicated process because choosing an optimum sand control method depends on different effective factors. These factors include the type of exclusion, gravel size of gravel pack and pre-packed screen, slot width and length of the slotted liner, PI reduction and operating costs. Optimum selection is further intricate due to the uncertainty associated with variables influencing sand control methods. Therefore, it is crucial to select the most appropriate method in terms of minimum skin (pressure drop), cost, and maximum net present value (NPV). Many authors have studied various well completion methods under different downhole conditions. Some of them have discussed sand production consequences, while, few specialists have worked on sand control method selection. Tausch and Corley (1958) found the economics and selection of the sand control method, based on bridging and consolidation of sand grains, is a function of the expected producing rate, time periods of workovers, location, and condition of wells. Tiffin et al. (1998) proposed new criteria for screen and gravel selection for sand control. These criteria are mainly based on reservoir sand size distribution. Hodge et al. (2002) developed a valuation method for a stand-alone screen design, and gravel packed completion with consideration of plugging resistance and sand retention. Denney (2002) worked on field and laboratory tests to evaluate the relative effectiveness of two types of sand control methods used in the field with respect to optimizing operating expense. Farrow et al.