API Publ 4702-2001 pdf free download

API Publ 4702-2001 pdf free download.Technologies to Reduce Oil and Grease Content of Well Treatment, Well Completion, and Workover Fluids for Overboard Disposal.
Technologies for treating non-produced fluids from offshore production operations were identified and evaluated in this research work, and based on a review of treatability data from this study, the technologies most suited for handling non-produced fluids from offshore operations are recommended. Recommendations for future research on those technologies are also provided. Environmental regulations placed on the disposal of treated produced water from offshore operations have become increasingly stringent. Environmental Protection Agency (EPA) specification of a 29 mg/L monthly average oil and grease effluent limit with a 42 mg/L daily maximum limit (Effluent limitation guidelines for the Oil and Gas Extraction Point Source Category, Best Available Technology, 40 CFR 435.13) has triggered the need for improved oil and grease removal prior to overboard discharge. A better understanding of the process upsets which contribute to poor disposal water quality is required (Bansal, 1993). One source of process upsets in de-oiling is flowback of non-produced fluids and their subsequent blending with main production streams. Non-produced fluids include well stimulation, well completion, and workover fluids. This study focused on non-produced fluids originating from well stimulation operations relying on the use of chemical formulations. This focus excluded well treatment operations involving formation fracturing through the use of explosives or hydraulic pressure, and well completion and workover operations requiring cements and high solids drilling fluids. In production operations, water is generally produced with crude oil, resulting in the formation of emulsions that are stabilized to some extent by naturally occurring compounds present at the oil/water interface. These emulsions are routinely handled on the production platform. The total produced stream is first treated with chemicals to destabilize the emulsion. The oil dispersed in produced water following the flowback of non-produced fluids is very different from that in the original production stream. Chemical constituents of non-produced fluids act to strongly stabilize the oil-in-water emulsions, rendering destabilization and phase separation difficult to achieve. These emulsions are responsible for increasing the oil and grease concentrations in discharged water. They also affect the quality of the dehydrated crude oil (Ali et al., 1997). The high degree of stability of these oil-in-water emulsions can be attributed to several factors, such as (Bansal, 1993; Ali, 1997; Caudle, 1996): • Acidizing additives, such as mutual solvents, surfactants, and corrosion inhibitors; • Precipitates formed during acidizing, including colloidal ferric hydroxides; • Iron (III) interactions with asphaltenes; • Oil-wetted solids, including corrosion and scale compounds and formation fines; and • Acidity of return non-produced fluids. Although the industry is engineering well stimulation formulations and procedures for satisfactory formation acidizing while reducing the impact of fluid returns on de-oiling facilities, these measures alone are not capable of eliminating operational problems (Bansal, 1993; Ali and Hill, 1997; Hebert and Khatib, 1996). As part of the development of these integrated system approaches, effective point-source treatment processes, designed to selectively remove contaminants responsible for stabilizing emulsions and inducing process upsets, need to be developed.
Findings from the information review are presented in this section. Chemical use and procedures are summarized in the following two subsections. Baseline oil and grease (O&G) data for produced water (PW), well stimulation chemicals, non-produced fluids (NPF), and combined fluids (CF) are then presented. WELL STIMULATION PROCEDURE Well stimulation chemicals and injection procedures currently used on offshore production platforms in the Gulf of Mexico were identified. Although well stimulation fluid compositions and injected volumes are often site-specific, all procedures share some fundamental similarities. Also, it was assumed that well stimulation formulations provided by the main service companies shared similar chemistry.