Innovative Approach of Rigless ESP and ICVs for Optimal Production and Recovery of Two Tight Reservoirs in Synergy
Authors: Saqib Talha , Mirza O. T. , Sabri A. M. , Al-Hajri S. S. 
Published: November 2024

The field discussed is located in the southern part of the Arabian Gulf, approximately 135 km northwest of Abu Dhabi city. This extensive and heterogeneous carbonate field comprises multi-stacked reservoirs, specifically Reservoirs A and B, which need to be developed in synergy to achieve better economics and extended well lives. Reservoir A holds an original oil in place (OOIP) of 869 million stock tank barrels (MMSTB) with 28°API oil and a saturation gas of 350 standard cubic feet per barrel (SCF/bbl), along with a reservoir pressure of approximately 4,200 psi. Reservoir B, on the other hand, has an OOIP of 460 MMSTB, with 34°API oil, a saturation gas of 400 SCF/bbl, and a reservoir pressure of about 4,300 psi.

Both reservoirs face challenges in flowing naturally due to low productivity and relatively low gas-oil ratios (GOR), compounded by a high sealine pressure exceeding 1,100 psi. To produce oil from these reservoirs, either the sealine pressure needs to be lowered, or artificial lift methods must be employed. After thorough evaluation, electric submersible pumps (ESPs) were chosen as the optimal artificial lift solution to counter the high sealine pressure. Developing these reservoirs individually was found to be uneconomical, leading to the adoption of an innovative approach that integrates surface-controlled inflow control valves (ICVs), rigless ESPs, and downhole chemical injection to develop both reservoirs interactively.

Individual appraisal wells confirmed the necessity of artificial lift for both Reservoir A and B. A state-of-the-art completion design was required to synergize the two reservoirs, incorporating surface control ICVs, artificial lift, chemical injection and downhole safety valve (DHSV). The chosen ESPs are rigless i.e. slickline deployable and retrievable, providing better control and reliability. The completion design features surface-controlled ICVs to control flow from each drain, with the rigless ESP pump positioned above the drains. Chemical injection is planned to be deployed below the ESP, and a tubing retrievable subsurface safety valve (TRSSV) with an appropriate larger internal diameter is designed to facilitate easy running and retrieval of the ESP, eliminating the need for barge or rig for any conventional slickline interventions.

For the lower completion, autonomous inflow control valves (AICVs) are used with compartmentalization to manage water breakthrough due to line drive water injection. Rigless ESPs were selected for their advantage in running and retrieving ESP parts through a conventional slickline unit, while ICVs offer surface control over the drains, and AICVs manage water breakthrough. The successful deployment of this design results in several key benefits: Conjunctive and accelerated developmentThe ability to replace pumps during the well's life without rig workoverReduced operational expenditure (OPEX) costsEconomical project

The proposed completion design provides significant advantages that can advance knowledge in the petroleum industry. These benefits include improved production performance and recovery, reduced operational costs and risks, enhanced reservoir management and optimization, extended well life and integrity, delayed water breakthrough, and minimized water production. The integration of intelligent completion, a rigless ESP system, surface-controlled ICVs, downhole chemical injection, and AICVs with compartmentalization can offer substantial value and insights for asset field development.