This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 20130, “Practical Approach for Solid Production Prediction and Completion Strategy Decisions in Horizontal Wells: A Case Study From a Cretaceous Carbonate Reservoir, North Oman,” by Mohammed Al-Aamri, Sandeep Mahajan, SPE, and Nair Sujith, Petroleum Development Oman, et al., prepared for the 2020 International Petroleum Technology Conference, Dhahran, Saudi Arabia, 13–15 January. The paper has not been peer reviewed. Copyright 2020 International Petroleum Technology Conference. Reproduced by permission.
The carbonate reservoir fields in Oman discussed in the complete paper are produced by several horizontal wells from long openhole sections. The wells are completed by barefoot (openhole) completion with electrical submersible pumps (ESPs) located in the wells’ buildup section. The field has experienced significant ESP failures, so a study aimed to provide input for well-completion-strategy design and operational parameters, which could minimize solids production and lower intervention/operating expenditure (OPEX). Based on the study results, recommendations were provided for a drawdown-management strategy, which potentially will benefit from increasing ESP run life and reducing field OPEX.
Petrophysical rock typing for the studied reservoir is detailed in the complete paper. The primary understanding of the root cause of these ESP failures was argillaceous rock typing along the horizontal section. The decision was made to recomplete the wells by isolating equipment from such rock typing. As a result, ESP run lives improved, but failures continued. Several wells featured an isolation process from the first day, for example, but run life did not improve.
The field team subsequently analyzed a sample of fines taken from the ESP, and their mineralogy was examined. The main finding was that almost 50% of the sample included calcite mineral content with some quartz (Fig. 1). However, the question remained as to which part of the reservoir the sample belonged.
All rock types potentially consist of such calcite minerals because of the marine-deposition environment. Hence, investigating and characterizing the possible root causes of the ESP failures, as well as providing effective completion mitigations for upcoming wells, was critical.
The key objectives of the study were to understand the mechanisms and causes of the observed solids from a geomechanical standpoint and to provide recommendations to minimize the risk of near-wellbore failure.