Investigation of a Novel Chemical for Bullhead Water Shutoff Treatments

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractTraditionally bullhead water control consists of the placement of water-soluble chemicals without mechanically isolating oil layers. In order to be successful, bullhead treatments should block water-bearing layers without affecting the permeability of the oil-bearing layers too much. This paper reports an experimental investigation of an innovative water shutoff chemical deemed suitable to accomplish this task. The chemical is soluble in oil without any reaction, and is transferred into and reacts with water to form a stable gel. Core flow experiments consisting mostly of the injection of either oil or water in cores containing the chemical dissolved in oil were performed to investigate the ability of the gel to reduce water permeability while maintaining oil permeability. To ensure that the results are relevant for designing field applications, the experiments were performed under conditions encountered in various sandstone reservoirs in the North Sea, Croatia and other regions. Permeabilities and temperature ranging from 100 to 300 mD and 70-90 0 C were therefore considered in this study. The influence of the other physical parameters, such as viscosity, concentration of active chemical in oil chemical, injection rate, etc., was also investigated.

Polymer Systems for Water Shutoff and Profile Modification: A Review Over the Last Decade

“…This amount increased to 249 million B/D in 2005 (Khatib 2007). Chemical methods include silicate (Grattoni et al 2001;Nasr-El-Din and Taylor 2005;Elewaut et al 2006;Al-Dhafeeri et al 2008;Boye et al 2011), resins (Seright et al 2003), cements, and polymer gels (Seright et al 2003;Sydansk 2007;Lightford et al 2008;Al-Muntasheri et al 2010). Water is also responsible for most of the corrosion and scale problems in the oil field (Donham 1991;Nasr-El-Din 2003;Merdhah and Yassin 2009;Al-Tolaihy and Bukhari 2010).…”

Disproportionate Permeability Reduction of Water-Soluble Silicate Gelants - Importance of Formation Wettability

“…Oil-soluble organically-modified silicate tetramethylorthosilicate (TMOS), also known as tetramethoxisilane, gelants were investigated by Elewaut et al (2005), Karmakar et al (2002), Thompson and Fogler (1997) and Grattoni et al (2002). The gelation process of such gelant involves the partitioning of tetramethylorthosilicate from the oil phase into the water phase.…”

Smart Technique in Water Shutoff Treatment for a Layered Reservoir through an Engineered Injection/Production Scheme

“…Gelant is supposed to form a gel network within the porous media. The efficiency of water shut off treatment depends on the compatibility of the gelant with harsh reservoir conditions as well as the proper placement of the gelant in water pathways, because the gel network blindly blocks any path that is occupied by the gelant. , Different gelant systems have been evaluated for this purpose, through micromodel, − packed bed, − and core flooding experiments. , …”

“…Therefore, gel treatments have been usually aimed to block the HP zones and fractures. In such circumstances, the permeability contrast between the layers is considered as a beneficial prospect for the formation that restricts the penetration of the gelant into the hydrocarbon rich low permeability (LP) layers. , However, gel invasion into the LP layers is still probable, since many parameters other than permeability contrast (such as injection rate, wettability, and porosity) control the gelant flow behavior . As a result, water shut off treatment sometimes leads to undesirable reduction in hydrocarbon production. , Several techniques have been proposed to improve the selective injection of the gelant into the HP layers.…”

“…Detailed studies showed that by increasing the gas production rate, the pressure gradient in the vicinity of the well exceeds the capillary resistance and induces water flow within these lenses. − In this case, most currently proven technologies that are based on blocking the HP layer lose their applicability. Considering the fluid flow behavior in heterogeneous porous media, it is stated that the selective injection of the gelant into the lower permeability lenses in competition with the adjacent HP layers is practically impossible, , and consequently the challenge requires innovative treatments. In this research based on the difference of dominant phases within the layers (e.g., saline water in the lower permeability layer and gas within the HP one), it is suggested that the clever utilization of smart salinity sensitive materials has the potential to solve the problem.…”