Formulation of cellulose using groundnut husk as an environment-friendly fluid loss retarder additive and rheological modifier comparable to PAC for WBM

The hydrocarbon extraction and exploitation using state-of-the-art modern drilling technologies urge the use of biodegradable, environment-friendly drilling fluid and drilling fluid additives to protect the environment and humanity. As more environmental laws are enacted and new safety rules implemented to oust the usage of toxic chemicals as fluid additives, it becomes inevitable that we re-evaluate our choice of drilling fluid additives. Drilling fluids and its additives play a crucial role in drilling operations as well as project costing; hence, it is needed that we develop cost-effective environment-friendly drilling fluid additives that meet the requirements for smooth functioning in geologically complex scenarios as well as have a minimal ecological impact. The current research work demonstrates key outcomes of investigations carried out on the formulation of a sustainable drilling fluid system, where groundnut husk is used as a fluid loss additive and a rheological modifier having no toxicity and high biodegradability. Cellulose was generated from groundnut husk at two varying particle sizes using mesh analysis, which was then compared with the commercially available PAC at different concentrations to validate its properties as a comparable fluid loss retarder additive as well as a rheological modifier. In the present work, various controlling characteristics of proposed groundnut husk additive are discussed, where comparison at different concentrations with a commercially available additive, PAC, is also validated. The API filtration losses demonstrated by the (63–74) µm and the (250–297) µm proposed additive showed a decrease of 91.88% and 82.31%, respectively, from the base mud at 4% concentration. The proposed husk additives acted as a filtrate retarder additive without much deviation from base rheology and with considerably higher pH than the base mud. This investigation indicates that the proposed fluid loss additive and rheological modifier can minimize the environmental hazards and have proved to be a cost-effective eco-friendly alternative in this challenging phase of the hydrocarbon exploration industry.

Experimental Investigation on The Effect of PolyVinyl Alcohol on Cement Fluid Loss in Oil Wells

This study presents the effect of PolyVinyl Alcohol Cement Fluid Loss Additive (PVA FLAC) on the API Filtration property of a cement slurry. In Cementing operations of oil wells, different type of fluid loss agents and chemicals are used based on the condition of the wells. PVA FLAC recently introduced in Kurdistan oil industry as loss agent additive to reduce the API Filtration Rate and fluid loss of the cement slurry. Four cementing formulations with different concentration of PVA FLAC additive prepared and their API filtration rates are measured. The results showed that when adding 1.94 gm, 2.91 gm and 3.88 gm of PVA FLAC additive to the cement slurry, the API Filtration Rate reduced by %17, %29 and %42, respectively. The new concentration significantly reduced the rate of filtration when compared to using only 0.97 gm of PVA FLAC additive.

Development of mathematical models to control the technological properties of cement slurries

Oil and gas producing enterprises are making increasingly high demands on well casing quality, including the actual process of injection and displacement of cement slurry, taking into account requirements for the annular cement level, eliminating possible hydraulic fracturing, with developing a hydraulic cementing program. It is necessary to prevent deep invasion of cement slurry filtrate into the formation to exclude bridging of productive layers. It is impossible to fulfill all these requirements at the same time without application of modifying additives; complex cement compositions are being developed and applied more often. Furthermore, need to adjust cement slurries recipes appears for almost every particular well. In order to select and justify cement slurries recipes and their prompt adjustment, taking into account requirements of well construction project, as well as geological and technical conditions for cementing casing strings, mathematical models of the main technological properties of cement slurries for cementing production casing strings in the Perm Region were developed. Analysis of the effect of polycarboxylic plasticizer (Pl) and a filtration reducer (fluid loss additive) based on hydroxyethyl cellulose (FR) on plastic viscosity (V), spreadability (S) and filtration (F) of cement slurries is conducted. Development of mathematical models is performed according to more than 90 measurements.

Salt-Tolerance Performance of Oil Well Cement Fluid Loss Additive SSS/HAM/IA

In order to study the effect of brine environment on the performance of oil well cement fluid loss additive (FLA) sodium p-styrene sulfonate/N-methylol acrylamide/itaconic acid (SSS/HAM/IA), the water loss of three different cement slurry systems added with different FLA additions (fresh water cement slurry, semi-saturated brine cement slurry and saturated brine cement slurry) were tested at 90°C and 150°C. The results show that SSS/HAM/IA has good salt tolerance. The water loss of three cement slurry systems was controlled within 100mL with FLA addition adjusted in the range of 1%~3% below 150 °C. The salt tolerance mechanism of SSS/HAM/IA was analyzed based on the microstructure of the three system terpolymer solutions characterized under environmental scanning electron microscopy (ESEM).

Function Synergy of a New Type of Fluid Loss Additive Formula for Comprehensive Performance of Oil Well Cement

With 2-acrylamido-2-methylpropanesulfonic acid (AMPS) units on polymeric additive, additive showed high effectiveness used for oilwell cement. However, due to chemical absorption and chelation mechanism of AMPS units to Ca2+ hydrating cement particles, adding of AMPS type additives caused delay of cement hydration process. In this research, AMPS type fluid loss additive, named as FLA A additive, was studied for its hydration delay side effect to class G Portland cement. Furthermore, polyvinyl alcohol (PVA) polymer, modified by glyoxal and boric acid, called as PVAGB was used as a synergistic functional additive to AMPS type polymer fluid loss additive to research on hydration delay problem of AMPS type additive to cement and the improvement for the effectiveness of AMPS type fluid loss additive. When AMPS type additive showed functional drawbacks, with more disordered chemical absorption and chelation behaviors to Ca2+ hydrated cement particles rather than constituting a completed and superior fluid loss control system, and this kind of modified PVA polymer was utilized for making up its failure. New compound additive formula, PVAGB/FLA A fluid loss additive formula, was investigated, which showed superior and more stable fluid loss control ability, i.e. about 50 mL at 30°C and 108 mL at 80 °C with just 0.2 % BWOC (weight percentage by weight of cement) PVAGB and 0.5 %BWOC (weight percentage by weight of cement) FLA A addition. In addition, within 28-day curing period, cement samples showed a healthy compressive-strength development with no less than 28MPa after 7-day curing period rather than failure due to cement strength retrogression. With scanning electron microscope (SEM) analysis, PVAGB showed accelerating effect to cement hydration process, in which hexagonal plate Ca(OH)2 crystal and aggregated product of C-S-H gel were formed when compared with pure cement and cement with FLA A additive added.