Development and First Application of an Ultra-Low Density Non-Aqueous Reservoir Drilling Fluid in the United Arab Emirates: A Viable Technical Solution to Drill Maximum Reservoir Contact Wells Across Depleted Reservoirs

Drilling and completion operations in depleted reservoirs, are challenging due to narrow margin between pore and fracture pressures. Therefore, Ultra-Low Density Reservoir Drilling Fluid (RDF) with optimum parameters is required to drill these wells safely. Design and effective field application of a sound engineered fluid solution to fulfill these operational demands are described. Ultra-Low Density RDF NAF with minimal fluid invasion characteristics was developed after extensive lab testing, to cover the fluid density from 7.2 – 8.0 ppg. The fluid properties were optimized based on reservoir requirements and challenging bottom-hole conditions. The design criteria benchmarks and field application details are presented. Fluids were stress tested for drill solids, reservoir water and density increase contamination. Multi-segment collaboration and teamwork were key during job planning and on-site job execution, to achieve operational success. For the first time in UAE, a major Offshore Operator successfully applied an Ultra-Low Density RDF-NAF, which provided remarkable stability and performance. The fluid was tested in the lab with polymeric viscosifier alone and in combination with organophilic clay. In order to gain rheology during the initial mixing, about 3.0 ppb of organophilic clay were introduced to system along with the polymeric viscosifier. Later, all the new fluid batches were built with polymeric additives alone to achieve target properties. A total of 10,250 ft of 8 ½" horizontal section was drilled to section TD with record ROP compared to previous wells in the same field, with no fluids related complications. With limited support from the solid control equipment, the team managed to keep the density ranging from 7.5 ppg to 7.8 ppg at surface condition, using premixed dilution. Bridging was monitored through actual testing on location and successfully maintained the target PSD values throughout the section by splitting the flow on three shaker screen size combination. Due to non-operation related issues, hole was kept static for 20 days. After such long static time, 8 ½" drilling BHA was run to bottom smoothly precautionary breaking circulation every 5 stands. Finally, after successful logging operation, 6 5/8" LEL liner was set to TD and the well completed as planned. Success of this field application indicates that an Ultra-Low density fluid can be designed, run successfully and deliver exemplary performance. Lessons learned are compared with conceptual design for future optimization. Laboratory test results are presented, which formed the basis of a seamless planned field application.

Batch and continuous of oil removal using organoclay and low-cost ceramic membrane

The objective of this work was to compare two oily effluent treatment systems, batch process and membrane separation process (PSM). In the batch process an organophilic clay was used and in the PSM a low cost ceramic membrane was used. A bofe clay was used as raw material for the preparation of organophilic clay prepared with surfactant, via direct method and characterized by X-ray diffraction. The sorption properties of this organoclay were evaluated to remove oil. The low-cost, disc-shaped ceramic membrane was obtained from natural bofe clay from Boa-Vista, Paraíba, Brazil. The uniaxial dry compaction method and sintering at 650 °C was used. The membrane was characterized by XRD and water permeability and its performance was evaluated by oil/water emulsion separation tests from a synthetic effluent, using a stainless steel module under the conditions of initial concentration of the emulsion 125 mg.L-1, temperature of 25 °C and pressure of 2.0 bar. It is concluded that the two processes (PSM and batch system using bofe organophilic clay as adsorbent) can be used and are promising for the treatment of oily water.

Modification of bentonite clay & its applications: a review

Bentonite clay is one of the oldest clays that humankind has been using from ancient times as traditional habits and remedies. In recent years researchers have found many applications of bentonite clay due to its various physio-chemical properties. In the present work, various physical and chemical properties of bentonite such as surface area, adsorption, swelling properties, cation exchange properties, etc. have been studied. This study also includes various procedures of modification of bentonite clay into Chitosan/Ag-bentonite composite, Fe-Modified bentonite, Hydroxyl-Fe-pillared-bentonite, Organo Bentonite, Organophilic clay, Arenesulfonic Acid-Functionalized Bentonite, Bentonite clay modified with Nb2O5. The study reveals that bentonite clay has large surface area due to similar structure with montmorillonite and it is found that the functionality of bentonite can be increased by increasing total surface area of the clay. Due to high cation exchangeability of bentonite, various cations can be incorporated into it. After purification and modification, the absorbent aluminum phyllosilicate bentonite clay can be used as an efficient catalyst in various types of catalytic reactions. Moreover, bentonite clay can be applied in various field like drilling, civil engineering, agriculture and water treatment.

Cement-Based Solidification/Stabilization of Soil Contaminated by Polycyclic Aromatic Hydrocarbons Using Organophilic Clay

The solidification/stabilization (S/S) method is the most widely used to remediate all types of inorganic pollutants, which has not been developed for organic matters. In this research, the application of cement and organophilic clay (OC) was investigated for the S/S of contaminated soil by polycyclic aromatic hydrocarbons (PAHs). Pyrene, Acenaphthene, Benzo[a]Pyrene, and Benz[a]Anthracene were spiked in a soil specimen. X-ray diffraction analysis (XRD) indicated that OC has a considerable ability to absorb PAHs in its inter-laminar molecular spaces, unlike ordinary bentonite. Toxicity characteristic leaching procedure (TCLP) results showed that application of OC increased PAHs' removal efficiency from contaminated soil up to 80% on average compared to the use of cement only. Samples containing 30% cement and 30% OC with a 14-day curing time had the best removal efficiency. Also, the removal efficiency of heavier PAHs was lower than the lighter ones. Additionally, unconfined compressive strength (UCS) showed a linear descending by increasing OC's proportion. Scanning electron microscopy (SEM) analysis indicated that two reasons have effectively increased the PAHs' removal efficiency of solid samples: a) increasing the amount of OC that increases the PAHs absorption capacity, b) reducing the size of pores in the matrix reduces the pollutant leaching.

The Optimal Formula for Organic Oil Immobilization in Algerian Petroleum Drill Cuttings Using Solidification/Stabilisation Treatment

Hassi Messaoud oil field is one of the most important fields in Algeria and the world, because it covers an important quantity of total Crude Oil Production in Algeria. Furthermore, two-thirds of this oil field is underexplored or not explored. Therefore, the drilling process of petroleum wells in this field is a continuous process that results in significant drilling waste. This implies that, enormous noxious quantities of drilling waste are produced daily that require treatment via solidification/stabilization (S/S) process before being landfilled. These types of wastes have pollution concentration that significantly exceeds the safety standards. In this study, we focus on the factors affecting the solidification/stabilization treatment of the drill cuttings obtained from Hassi Messaoud oil field and the process optimization. The solidification/stabilization is performed using the cement as binder, sand, silicate, organophilic clay and activated carbon as additives. The study is divided in two steps: (i) aims to determine the optimum ratio of each element used in the S/S process for the organic element (hydrocarbon) elimination, (ii) aims to combine the optimum ratios found in the previous step to determine the optimal mixture. The obtained results in the first step showed that the optimum ratio for the cement-to-drill cuttings mass ratio is 0.09:1. For the additives-to-drill cuttings mass ratio are 0.04:1, 0.006:1, 0.013:1 and 0.013:1 for the sand, sodium silicate, Organophilic clay and activated carbon, respectively. An optimum formula is found which its main finding shows that the hydrocarbon content of our sample is dropped from 9.40 to 1.999%. Many tests results before landfilling were investigated such as matrix permeability, resistance to free compression and heavy metals rate before and after S/S process. Besides that, in the light of outcomes achieved by this assessment these harmful cuttings can be converted into a useful product that helps in reducing the environmental foot prints.

The effect of clay organophilization on wood plastic composite (WPC) based on recycled high density polyethylene (HDPE) and coir fiber

One way to optimize composite mechanical properties is through hybridization with small amounts of reinforcing fillers. Thus, this study investigates the effect of incorporation of 3 wt% of clay (BT) and organoclay (OBT) on the properties of a recycled wood plastic composite (WPC) based on HDPE and 20 wt% of coir fiber compounded with 5 wt% of maleic anhydride-grafted polypropylene (PP-g-MA), as coupling agent, and 5 wt% of Struktol TPW 113, as lubricating agent. Raw materials were characterized by X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Coir fiber was characterized by optical microscopy and TGA. Wood plastic formulations (with clay and organoclay) were prepared in an internal mixer coupled to a torque rheometer operating at 190°C, 60 rpm for 10 min. Then, the mixtures were compression molded. Formulations were characterized by SEM, TGA, DSC, tensile and water absorption tests. FTIR analysis showed the characteristic bands of organophilic clay. XRD showed an increment in the interplanar distance of the clay, after the incorporation of quaternary ammonium salt (distearyl dimethyl ammonium chloride, Praepagen® WB), confirming the organoclay formation. Organophilization decreases the clay hydrophilic character and reduces the water uptake of WPC-BT. Despite the fact that BT incorporation led to WPC nanocomposite with intercalated structure, this WPC-clay composition did not show a significant increase in tensile strength and elongation at break. The poor interfacial adhesion between the raw materials and the polymer matrix, the low aspect ratio provided by coir fibers and also, the partially intercalated structure of composites have contributed to this behavior.

A Characteristic Study of Polylactic Acid/Organic Modified Montmorillonite (PLA/OMMT) Nanocomposite Materials after Hydrolyzing

In this study, the montmorillonite (MMT) clay was modified with NH4Cl, and then the structures were exfoliated or intercalated in a polylactic acid (PLA) matrix by a torque rheometer in the ratio of 0.5, 3.0, 5.0 and 8.0 wt%. X-ray diffraction (XRD) revealed that the organic modified-MMT(OMMT) was distributed successfully in the PLA matrix. After thermal pressing, the thermal stability of the mixed composites was measured by a TGA. The mixed composites were also blended with OMMT by a co-rotating twin screw extruder palletizing system, and then injected for the ASTM-D638 standard specimen by an injection machine for measuring the material strength by MTS. The experimental results showed that the mixture of organophilic clay and PLA would enhance the thermal stability. In the PLA mixed with 3 wt% OMMT nanocomposite, the TGA maximum decomposition temperature (Tmax) rose from 336.84 °C to 339.08 °C. In the PLA mixed with 5 wt% OMMT nanocomposite, the loss of temperature rose from 325.14 °C to 326.48 °C. In addition, the elongation rate increased from 4.46% to 10.19% with the maximum loading of 58 MPa. After the vibrating hydrolysis process, the PLA/OMMT nanocomposite was degraded through the measurement of differential scanning calorimetry (DSC) and its Tg, Tc, and Tm1 declined.

Impact of organophilic clay on rheological properties of gasoil-based drilling muds

In this study, the impact of VG69 organophilic clay on the rheological properties of gasoil-based drilling muds (invert emulsions) was investigated. The flow curves of gasoil-based drilling muds as a function of the dose of VG69 organophilic clay were analyzed by the Casson model. The addition of VG69 organophilic clay with a quantity range between 0 and 5 g in gasoil-based drilling muds induces an increase in the yield stress and the viscosity at an infinite shear rate of drilling muds. It is also proven that the addition of VG69 organophilic clay leads to an increase in the viscoelastic and thixotropic properties of the drilling muds. The study of the stability of gasoil-based drilling muds by centrifugation showed that for a quantity of VG69 organophilic clay lower than 3 g, the stability of the drilling muds increases and for a quantity of VG69 organophilic clay higher than 3 g, their stability decreases. The results obtained showed that the addition of 3 g of VG69 organophilic clay to the gasoil-based drilling mud increased the yield stress by 230%, the viscosity at an infinite shear rate by 3.4% and it improved the mud stability by 70%.