A New Method to Design and Optimize the ICD for Horizontal Wells

Abstract

Abstract QHD oilfield in Bohai Bay, China, is characterized by conventional heavy oil (average viscosity 150cp under reservoir conditions) with excellent reservoir quality (up to 30% porosity and 1-2D permeability) and strong aquifer. Horizontal and multilateral wells are widely used in QHD and most wells were standard completion. After 13 years of development, many wells show sharp production decline and rapid water cut increase. What's more, water breakthrough in several wells is much earlier than prediction. The high mobility ratio, hell-toe effect, bottom water, permeability heterogeneity and sand are contributed to reduced ultimate recovery and well life. The use of ICD (inflow control device) is becoming more and more prevalent as it can delay the water break through and significantly improve the economic life of a well. This is especially important for offshore fields where well intervention is difficult and expensive. Therefore, ICD technique is proposed to address the above production problem while prolonging production life (BREKKE K, 1997). In this paper, I discuss the feasibility of ICD for horizontal wells in heavy oil reservoir of offshore field. First, I analyze the actuality of the offshore heavy oil with strong bottom water in Bohai Bay and the reason of bottom water coning. Secondly, I discuss the feasibility of ICD for horizontal wells in heavy oil reservoir of offshore field. Finally, a new method is established to design the additional pressure of ICD. The method is compared to the uniform liquid method; what's more, a numerical model is developed to validate the new method. The production performance of the first ICD wells was discussed to provide evidence on its effectiveness and robustness. This has provided valuable data prior to well drilling and the final optimization of ICD. The paper demonstrates the importance of seamless teamwork and coordination between reservoir engineers and project team to deliver superior performance. In a word, this paper is expected to assist well completion decisions for offshore heavy oil reservoir and to spark continue research on ICD.