A Customized High Performance Water-Based Mud Solved the Challenge to Drill Reactive Shale Formation and Simplify the Logistic Challenge in an Exploration Well in Offshore East Kalimantan, Indonesia

2021 ◽  
Author(s):  
Djoko Pinartjojo ◽  
Edison Tamba Tua Hutahaean ◽  
Ian McManus ◽  
Aphrizal S. I. N. Nerwan ◽  
Rudiny Hansen

Abstract Exploration drilling obviously requires a robust drilling fluid system to be a key factor in overcoming both the known and unexpected challenges of a structure that consists of reactive clay and lost circulation zones. Extra consideration has to be given to regulatory environmental requirements and complications resulting from regional politics. A High-Performance Water Based Mud (HPWBM) system was selected to address the aforementioned issues. The HPWBM was customized to respond to the subsurface conditions with the main requirement to provide maximum shale inhibition through a non-dispersed environment. Polyamine was utilized to stabilize all types of clay; an encapsulation polymer and a non-ionic polymer were included to prevent dispersion and to seal micro-fractures. A complete shale study was performed to determine the optimum concentration of the base fluid and each shale inhibitor. Then hydraulic behaviour of the mud was simulated with contractor proprietary software to understand the parameters for optimal hole cleaning as well as Equivalent Circulating Density (ECD) simulation. The HPWBM system successfully facilitated the execution of the exploration well and provided highly effective clay stabilization. No Non-Productive Time (NPT) was recorded as a result of reactive clay issues. The mud system also facilitated a good rate of penetration (ROP), formation stability, and lubricity. Waste cuttings transportation was not required. In addition, there is also no requirement for costly base oil including its associated transportation costs. The successful implementation of the HPWBM yielded an estimating saving of 25% compared to invert emulsion fluids, prior to considering costs associated with an expensive Liquid Mud Plant (LMP), environmental, and freight costs. Significant cost savings were achieved by eliminating the need for LMP rental, mobilization and demobilization. Another notable saving was realized from the reduced system maintenance of the HPWBM as less dilution was required compared to a regular Water Based Mud. Thinking outside of the box and embracing the departure from the default consideration of an invert system with a thorough risk assessment augmented value to wellbore construction. A smartly designed HPWBM system provided performance comparable to an invert emulsion system but with superior benefits with respect to environmental protection, simplified logistics and lower costs.

SPE Journal ◽  
2016 ◽  
Vol 21 (05) ◽  
pp. 1755-1766 ◽  
Author(s):  
Wai Li ◽  
Xionghu Zhao ◽  
Yihui Ji ◽  
Hui Peng ◽  
Bin Chen ◽  
...  

Summary As a type of mono-alkyl ester, biodiesel exhibits great potential to serve as the base oil of drilling fluids substituting for conventional oil-based drilling fluids (OBDFs). This paper presents a series of laboratory investigations of water-in-biodiesel (invert) emulsion as the basis of a high-performance, environmentally friendly, and low-cost biodiesel-based drilling fluid (BBDF). Biodiesel produced from waste cooking oil was used to formulate a BBDF because of its high flashpoint, reliable storage stability, acceptable elastomeric material compatibility, nontoxicity, and excellent biodegradability. In light of the results of tests used to measure various properties, the biodiesel invert-emulsion chemistry, including the required hydrophile/lipophile balance (HLB), optimal emulsifier, effects of different additives (organophilic clay, calcium chloride, and lime), as well as hydrolytic stability, was studied. A biodiesel invert emulsion that remains stable after hot rolling at 120°C for 16 hours can be prepared with correct combinations of additives, thereby offering a firm foundation for designing BBDFs. The novel emulsifier package developed in this work is introduced as an achievement in the comprehensive usage of waste cooking oil because its feedstock is identical to that of biodiesel. An initial economic analysis of the use of biodiesel for drilling is also presented. Details of the formulations and properties of BBDFs derived from this fundamental research are discussed in another paper (Part 2).


2021 ◽  
Author(s):  
Vikrant Wagle ◽  
Abdullah Yami ◽  
Michael Onoriode ◽  
Jacques Butcher ◽  
Nivika Gupta

Abstract The present paper describes the results of the formulation of an acid-soluble low ECD organoclay-free invert emulsion drilling fluid formulated with acid soluble manganese tetroxide and a specially designed bridging package. The paper also presents a short summary of field applications to date. The novel, non-damaging fluid has superior rheology resulting in lower ECD, excellent suspension properties for effective hole cleaning and barite-sag resistance while also reducing the risk of stuck pipe in high over balance applications. 95pcf high performance invert emulsion fluid (HPIEF) was formulated using an engineered bridging package comprising of acid-soluble bridging agents and an acid-soluble weighting agent viz. manganese tetroxide. The paper describes the filtration and rheological properties of the HPIEF after hot rolling at 300oF. Different tests such as contamination testing, sag-factor analysis, high temperature-high pressure rheology measurements and filter-cake breaking studies at 300oF were performed on the HPIEF. The 95pcf fluid was also subjected to particle plugging experiments to determine the invasion characteristics and the non-damaging nature of the fluids. The 95pcf HPIEF exhibited optimal filtration properties at high overbalance conditions. The low PV values and rheological profile support low ECDs while drilling. The static aging tests performed on the 95pcf HPIEF resulted in a sag factor of less than 0.53, qualifying the inherent stability for expected downhole conditions. The HPIEF demonstrated resilience to contamination testing with negligible change in properties. Filter-cake breaking experiments performed using a specially designed breaker fluid system gave high filter-cake breaking efficiency. Return permeability studies were performed with the HPIEF against synthetic core material, results of which confirmed the non-damaging design of the fluid. The paper thus demonstrates the superior performance of the HPIEF in achieving the desired lab and field performance.


Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Sneha Sayindla ◽  
Bjørnar Lund ◽  
Benjamin Werner ◽  
...  

One important requirement for a drilling fluid is the ability to transport the cuttings out of the borehole. Improved hole cleaning is a key to solve several challenges in the drilling industry and will allow both longer wells and improved quality of well construction. It has been observed, however, that drilling fluids with similar properties according to the API standard can have significantly different behavior with respect to hole cleaning performance. The reasons for this are not fully understood. This paper presents results from flow loop laboratory tests without and with injected cuttings size particles using a base oil and a commercial oil based drilling fluid. The results demonstrate the importance of the rheological properties of the fluids for the hole cleaning performance. A thorough investigation of the viscoelastic properties of the fluids was performed with a Fann viscometer and a Paar-Physica rheometer, and was used to interpret the results from the flow loop experiments. Improved understanding of the fluid properties relevant to hole cleaning performance will help develop better models of wellbore hydraulics used in planning of well operations. Eventually this may lead to higher ROP with water based drilling fluids as obtained with oil based drilling fluids. This may ease cuttings handling in many operations and thereby significantly reduce the drilling cost using (normally) more environmentally friendly fluids. The experiments have been conducted as part of an industry-sponsored research project where understanding the hole cleaning performance of various oil and water based drilling fluids is the aim. The experiments have been performed under realistic conditions. The flow loop includes a 10 meter long test section with 2″ OD freely rotating drillstring inside a 4″ ID wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal position.


2021 ◽  
Author(s):  
Farqad Hadi ◽  
Ali Noori ◽  
Hussein Hussein ◽  
Ameer Khudhair

Abstract It is well known that drilling fluid is a key parameter for optimizing drilling operations, cleaning the hole, and managing the rig hydraulics and margins of surge and swab pressures. Although the experimental works present valid and reliable results, they are expensive and time consuming. On the other hand, continuous and regular determination of the rheological mud properties can perform its essential functions during well construction. More uncertainties in planning the drilling fluid properties meant that more challenges may be exposed during drilling operations. This study presents two predictive techniques, multiple regression analysis (MRA) and artificial neural networks (ANNs), to determine the rheological properties of water-based drilling fluid based on other simple measurable properties. While mud density (MW), marsh funnel (MF), and solid% are key input parameters in this study, the output functions or models are plastic viscosity (PV), yield point (YP), apparent viscosity (AV), and gel strength. The prediction methods were demonstrated by means of a field case in eastern Iraq, using datasets from daily drilling reports of two wells in addition to the laboratory measurements. To test the performance ability of the developed models, two error-based metrics (determination coefficient R2 and root mean square error RMSE) have been used in this study. The current results of this study support the evidence that MW, MF, and solid% are consistent indexes for the prediction of rheological properties. Both mud density and solid content have a relative-significant effect on increasing PV, YP, AV, and gel strength. However, a scattering around each fit curve is observed which proved that one rheological property alone is not sufficient to estimate other properties. The results also reveal that both MRA and ANN are conservative in estimating the fluid rheological properties, but ANN is more precise than MRA. Eight empirical mathematical models with high performance capacity have been developed in this study to determine the rheological fluid properties based on simple and quick equipment as mud balance and marsh funnel. This study presents cost-effective models to determine the rheological fluid properties for future well planning in Iraqi oil fields.


2018 ◽  
Vol 58 (1) ◽  
pp. 112
Author(s):  
Son Ly ◽  
Xiao Yu ◽  
Xinsong Zhang ◽  
Alireza Salmachi

High performance water-based drilling fluid alternatives that meet performance objectives with minimal environmental impact must continually be developed. Drilling fluid performance is dependent on fluid characteristics, and among those most critical are viscosity and filtration. One avenue to improve drilling fluid performance is through enhancement by use of potent, water-soluble natural polymers. Psyllium husk powder is an environmentally friendly natural polymer derived from ground-up surfaces of psyllium seeds (Plantago ovata). When in contact with water, psyllium husk powder forms a gel-like, extraordinarily viscous substance at very low concentrations. It was previously shown that pure psyllium husk is an excellent viscosity and filtration agent for water-based drilling fluid under standard conditions. Psyllium husk can also be used as a clay-extender to enhance viscosity and filtration performance of bentonite mud; however, further laboratory testing of this performance enhancement under elevated temperatures and pressures is required. Extensive laboratory experiments were therefore conducted to test husk performance in bentonite mud under such conditions. An electronic rheometer and a temperature and pressure adjustable API filter press were used to evaluate viscoelastic and filtration mud characteristics respectively. Concentrations of 0.05–0.4% husk with 5% bentonite were tested at 25−120°C under 1500 psi. An optimal husk concentration of 0.1% was determined, increasing bentonite viscosity and yield point by up to 46.9% and 68.1% respectively. Filtrate loss rate and filtration cake thickness were reduced by up to 25.8% and 35.3% respectively. The optimal concentration was useable up to 70°C (~2800 m) before deflocculating was required.


2020 ◽  
Author(s):  
Xian-Bin Huang ◽  
Jin-Sheng Sun ◽  
Yi Huang ◽  
Bang-Chuan Yan ◽  
Xiao-Dong Dong ◽  
...  

Abstract High-performance water-based drilling fluids (HPWBFs) are essential to wellbore stability in shale gas exploration and development. Laponite is a synthetic hectorite clay composed of disk-shaped nanoparticles. This paper analyzed the application potential of laponite in HPWBFs by evaluating its shale inhibition, plugging and lubrication performances. Shale inhibition performance was studied by linear swelling test and shale recovery test. Plugging performance was analyzed by nitrogen adsorption experiment and scanning electron microscope (SEM) observation. Extreme pressure lubricity test was used to evaluate the lubrication property. Experimental results show that laponite has good shale inhibition property, which is better than commonly used shale inhibitors, such as polyamine and KCl. Laponite can effectively plug shale pores. It considerably decreases the surface area and pore volume of shale, and SEM results show that it can reduce the porosity of shale and form a seamless nanofilm. Laponite is beneficial to increase lubricating property of drilling fluid by enhancing the drill pipes/wellbore interface smoothness and isolating the direct contact between wellbore and drill string. Besides, laponite can reduce the fluid loss volume. According to mechanism analysis, the good performance of laponite nanoparticles is mainly attributed to the disk-like nanostructure and the charged surfaces.


2018 ◽  
Vol 765 ◽  
pp. 106-112
Author(s):  
Yin Bo He ◽  
Guan Cheng Jiang ◽  
Wu Ge Cui

In this study, we report salt-responsive amphoteric terpolymers prepared by copolymerization of acrylamide (AM), 2-acrylamido-2-methylpropanesulfonate (AMPS) and 3-acrylamidopropyl trimethylammonium chloride (ATC), and their use as rheology and fluid loss modifiers in water-based drilling fluid (WDF). The dependence of viscosity and turbidity on NaCl concentration indicates the salt-responsiveness of terpolymers, which results from salt-induced polymer conformation changes. In the presence of large quantities of NaCl, comparing with BT/polyanioins solution, bentonite (BT)/terpolymer solution has better shear thinning and thixotropic performance as well as lower fluid loss. Morphology shows that BT/terpolymer solution with NaCl creates high-quality filtrate cake which is compact and thin. A salt-resistant WDF prepared with terpolymers is evaluated and compared with polyanioinc WDF and polyanionic sulfonated WDF. The salt-resistant WDF possesses more favorable rheology, lower fluid loss and stronger tolerance for temperature, suggesting the potential use of AM/AMPS/ATC terpolymers as high-performance additives for salt-resistant WDFs.


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