Evaluation and Selection of Surface and Production Casings for the New Wells at Eti Soda’s Beypazari Trona Deposits

Abstract

Sodium carbonate (Na₂CO₃) and sodium bicarbonate (NaHCO₃) are extracted through solution mining at Eti Soda’s Beypazari trona deposits in Turkey. Eti Soda will drill nineteen vertical wells and ten directional wells to develop ten new caverns, with an average depth of about 450 meters (m). This paper discusses methodology for evaluating stability of surface and production casings for the new wells during solution mining. The methods used for this study include: 1) numerical modeling and 2) the method prescribed by the American Petroleum Institute/International Organization for Standardization (API/ISO). The API/ISO method is more suitable for evaluating casing integrity while a casing is being run or shortly after it has been cemented. The numerical modeling method can analyze complicated loading conditions on a casing during solution mining. The numerical modeling method was used as the primary method for evaluation of deformation and stresses of casings for the new wells. The API/ISO method was used as an ancillary method to check the competency of the selected casings based on the modeling results. This study guides the selection of casings for the new wells that have enough strength to withstand most loadings during solution mining without an excessive degree of capacity and durability.

1. INTRODUCTION

Sodium carbonate (Na₂CO₃) and sodium bicarbonate (NaHCO₃) are extracted from multiple trona beds through solution mining at Eti Soda’s Beypazari trona deposits in Turkey. Eti Soda will drill nineteen vertical and ten horizontal wells to develop ten new caverns U6- P045 to U6-P054, as shown in Fig. 1. The depth of cover of these caverns is about 450 m on average. According to the initial well-casing completion plan, 273- millimeter (mm) (10¾-inch [in]), 60-kilograms per meter (kg/m) (40.5-pound per foot [ppf]), J55 casing would be used for the 270-meter (m)-long surface casing. For the vertical wells, 178-mm (7-in), 39-kg/m (26-ppf), J55 and P110 were chosen for the upper 250-m and lower 200-m production casings, respectively. For the horizontal wells, 178-mm (7-in), 39-kg/m (26-ppf), J55 would be used for the production casing.