Organic Deposition: From Detection and Laboratory Analysis to Treatment and Removal

Abstract

Organic deposition predominantly in the near well bore and in production tubing can create serious oilfield problems such as flow restrictions, near wellbore damage, efficiency of crude processing units and etc. As the reservoir depleted over the time, the solid deposition can lead to a steep decline in productivity of wells. The deposition of organic solids is one of many flow assurance problems faced by operators in Malaysia. It has been observed that, after years of production, many fields in Malaysia are suffering from organic solid deposition problem. This phenomenon is predominantly caused by changes in temperature, pressure and composition/morphology of the crude oil over time. To perform organic deposit removal treatment and prevention in the well, the nature of the solid should be characterized. If the deposit sample is organic mainly, it is important to quantify the various organic fractions of the solid sample collected from the production facilities. This paper explains how SARA analysis was modified to detect not only Macro-crystalline waxes (Saturates), asphaltene, aromatics and resins but also micro-crystalline wax and naphthenates. The content of each of above component will affect the method of treatment and the chemical formulation to treat the well. By knowing the composition of the solid sample along with Crude’s Colloidal instability index (CII), Pour point and Wax Appearance Temperature (WAT), a customized chemical formulation can be designed. Lab studies were performed on solid samples collected from several wells to detect the flow assurance related issues prior to design of chemical formulation. With the analysis of the production data, history matching, and etc, a customized chemical formulation was developed to treat the wells. The proposed chemical formulation consists of 2 specially designed pills which would be simultaneously injected to the wellbore, which generates heat and ester once comingles. The heat melts the deposits while the ester disperses the melted solid. The initial studies of the treatment showed promising results; moreover the field implementation was very successful and proven significant increase in production rate. This novel system that combines both thermal and physical energy, evidenced to work effectively for wide range of organic compositions. Implementation of this system made it possible to restart the production from those wells which were idle due to extensive organic deposits. This technique was also often used to rejuvenate the old wells with low production rate. This paper discusses the diagnostic process and successful implementation of the proposed treatment in several oil wells in Malaysia.

Solid Phase Deposition Pattern Concerning Formation Oil in YD 7 Reservoir of Tarim Oilfield and Its Application: A Case Study

“…When the temperature decreases from the high temperature above the deposition point to the vicinity of the precipitation point, the value of the inflection point when the heat flow rises is the initial deposition temperature of the solid phase. As the system temperature continues to decrease, the components in the crude oil gradually precipitate into solid phase crystals from heavy components to light components, and the cumulative deposition of solid phase in the crude oil gradually increases. − Since the precipitation process of solid phase in crude oil is similar to the wax precipitation process, the same method can be used to quantitatively analyze the precipitation process and the amount of wax in crude oil in this study. The calculation steps are as follows.…”

Research Progress in Nanoparticle Inhibitors for Crude Oil Asphaltene Deposition

“…Many studies showed that most crude oil exists in a relatively stable colloidal dispersion system under formation conditions, and asphaltenes are affected by many factors during deposition. Alian et al [ 41 ] found that the stability of asphaltenes depends on the composition, pressure, and temperature of crude oil. Among them, the influence of constituent factors is greater.…”

Detection and Removal of Naphthenate Deposit in Oil Well

“…Modified SARA analysis was conducted to determine the content of saturates, aromatics, resins and asphaltene. The modified in-house version of SARA is also able to detect microcrystalline wax and naphthenates which are usually overlooked in routine SARA analysis [3]. The deposit sample analyzed from Well BM-1 as given in Table 1 above is mostly inorganics containing corrosion products/clay etc.…”