Reservoir Formation Damage; Reasons and Mitigation: A Case Study of the Cambrian–Ordovician Nubian ‘C’ Sandstone Gas and Oil Reservoir from the Gulf of Suez Rift Basin

Abstract

Reservoir formation damage is a major problem that the oil and gas industry has to mitigate in order to maintain the oil and gas supply. A case study is presented that identifies the impacts of formation damage and their causes in the Nubian ‘C’ hydrocarbon reservoir within Sidki field located in the Southern Gulf of Suez, Egypt. In addition, a formation damage mitigation program was designed and implemented involving an effective stimulation treatment for each well experiencing reservoir damage. The data available for this study include core analysis to provide rock mineralogy and lithology; analysis of production fluid data; water chemistry; drilling fluid composition; perforations and well completion details; workover operations; and stimulation history. The diagnosis of formation damage based on the integrated assessment of the available data is associated with several benefits, (1) The integration of the data available helps provide a robust analysis of formation damage causes and in establishing suitable remediation actions, (2) Workover fluid is confirmed as the primary cause of reservoir damage in the studied well, (3) Several reservoir damage mechanisms were identified including water blockage, solids and filtrate invasion, fluid/rock interaction (deflocculation of kaolinite clay), salinity shock and/or high-sulfate content of the invaded fluid, (4) Irrespective of the potential causes of formation damage, the primary objective of a gas production company is to mitigate its effects and the integrated dataset helps to design appropriate and effective stimulation treatments to overcome formation damage, and (5) In gas reservoirs, especially low permeability ones, extra precautions are necessary to avoid potential reservoir damage due to workover fluid invasion.

A multi-proxy approach to detect the pore pressure and the origin of overpressure in sedimentary basins: An example from the Gulf of Suez rift basin

“…As evidenced by geophysical and borehole data, the basin is filled with more than a 5-km-thick sedimentary sequence ranging from the Precambrian to the Quaternary (Metwalli et al, 1981;Metwalli et al, 1982;El-Hattab, 1982;Montenat et al, 1988;EGPC, 1996;Radwan, 2022b), which is punctuated by several unconformities of different magnitudes and ages (Figure 3). The studied area of El Morgan oil field is situated in the south central offshore area of the rift basin, where numerous hydrocarbon plays are present (Figure 3) (Alsharhan and Salah, 1995;EGPC, 1996;Bosworth and McClay, 2001;Barakat et al, 2002;Youssef et al, 2002;Alsharhan, 2003;Radwan, 2014;Attia et al, 2015;Abudeif et al, 2016a;El Ayouty, 2017;Abudeif et al, 2018;Radwan, 2018;Radwan et al, 2019a;Radwan et al, 2019b;Radwan et al, 2019c;Radwan et al, 2020a;Radwan et al, 2020b;Radwan et al, 2020c;Radwan et al, 2021c;Radwan et al, 2021d;Radwan et al, 2021e;Ali et al, 2022). El Morgan field is located on the southwest coast of the Sinai Peninsula, covering an area of roughly 46 km 2 (Bentley and Biller, 1990;Radwan, 2014;Attia et al, 2015).…”

“…El Morgan field is classified as the biggest giant oil field in Egypt with more than 1.5 BBO reserves. The stratigraphic sequence of El Morgan oil field is classified into three main depositional mega sequences, namely pre-rift, syn-rift, and post-rift (Brown, 1980;Attia et al, 2015;Abudeif et al, 2016a;Abudeif et al, 2016b;Radwan et al, 2019b;Radwan et al, 2019c;Radwan, 2021a;Radwan, 2021b;Radwan, 2021c;Radwan et al, 2021c;Radwan et al, 2021d;Radwan et al, 2021e). The deposition of sediments in the study area took place in different depositional environments (EGPC, 1996).…”

Formation-Damage Mechanism and Gel-Breaker-Free Drill-In Fluid for Carbonate Reservoir

“…The damage of such reservoir formations can be generated by multiple sources [ 13 ]. The mechanisms of reservoir damage can be classified into four types: mechanical; chemical; biological; and thermal processes [ 14 , 15 , 16 ]. Studies and explorations have indicated that the subsalt carbonate formations in the Middle East have strong heterogeneity.…”

Study Correlation between Physical-Mineralogical Properties of Sandstone Used in Ptolemaic Temples in Upper Egypt and Its Weathering Resistance

“…There are minerals such as halite, clay minerals and iron oxides, found within the components of sandstone, where these minerals are subjected to change when interacting with various damage factors [13] [14]. Wet and dry cycles cause complex mechanical damage in particular when salts are found in the pores of the stone; because it is characterized by high porosity, so it has ability to absorb moisture from air or ground, thus facilitating penetration of salts spray into its components causing physiochemical damage, especially when the dissolved salts turn to different crystalline sizes, causing cracks in internal structure of the stone [15], because sodium chloride salt is hygroscopic and tends to absorb water, the presence of water causes the salt crystal to expand, creating pressures and tensions inside the stone that cause disintegration of the binding material of sandstone; the stone's containment of iron compounds makes it vulnerable to oxidation, such as the transformation of ferrous compounds into ferric compounds, where iron compounds change the color of the stone, and ferric compounds increase in size when they acquire water of crystallization, causing stresses in the stone's structure, which accelerates the process of damage, and this phenomenon is known stone disease [16] [17]. Most sandstone has clays in the cement that binds the grains together.…”