Low-Damage Drilling Fluid Technology Used in Jabung Oilfield, Indonesia

2011 ◽  
Vol 347-353 ◽  
pp. 1627-1632
Author(s):  
Jiao Jiao Geng ◽  
Jie Nian Yan ◽  
Wen Yi Chen ◽  
Chun Yao Peng ◽  
Jing Jie Zuo ◽  
...  

Formation damage is prone to occur during drilling into the formations with medium/high permeability in Jabung Oilfield, Indonesia. To prevent formation damage and enhance productivity of oil wells, a novel low-damage drilling fluid was developed on the basis of the modification of currently used KCl polymer drilling fluid using a special technology. By virtue of the synergistic effect of ideal packing agents and film-forming agents, a sealing layer with high pressure bearing capability can be formed on the rock surface of borehole, so as to prevent drilling fluids from invading into formations effectively. It is shown from the results of numerous experiments that this drilling fluid has excellent rheological properties, very low filtration rates (API filtration rate<4mL and HTHP filtration rate≤12.5mL), good lubricity, and strongly inhibitive character to shale. Also, it exhibits remarkable effectiveness of formation protection indicated by the returned permeability as high as 88.11% and extremely low dynamic filtration rate lower than 4mL.

Author(s):  
Erfan Veisi ◽  
Mastaneh Hajipour ◽  
Ebrahim Biniaz Delijani

Cooling the drill bit is one of the major functions of drilling fluids, especially in high temperature deep drilling operations. Designing stable drilling fluids with proper thermal properties is a great challenge. Identifying appropriate additives for the drilling fluid can mitigate drill-bit erosion or deformation caused by induced thermal stress. The unique advantages of nanoparticles may enhance thermal characteristics of drilling fluids. The impacts of nanoparticles on the specific heat capacity, thermal conductivity, rheological, and filtration control characteristics of water‐based drilling fluids were experimentally investigated and compared in this study. Al2O3, CuO, and Cu nanoparticles were used to prepare the water-based drilling nanofluid samples with various concentrations, using the two-step method. Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) were utilized to study the nanoparticle samples. The nanofluids stability and particle size distribution were, furthermore, examined using Dynamic Light Scattering (DLS). The experimental results indicated that thermal and rheological characteristics are enhanced in the presence of nanoparticles. The best enhancement in drilling fluid heat capacity and thermal conductivity was obtained as 15.6% and 12%, respectively by adding 0.9 wt% Cu nanoparticles. Furthermore, significant improvement was observed in the rheological characteristics such as the apparent and plastic viscosities, yield point, and gel strength of the drilling nanofluids compared to the base drilling fluid. Addition of nanoparticles resulted in reduced fluid loss and formation damage. The permeability of filter cakes decreased with increasing the nanoparticles concentration, but no significant effect in filter cake thickness was observed. The results reveal that the application of nanoparticles may reduce drill-bit replacement costs by improving the thermal and drilling fluid rheological characteristics and decrease the formation damage due to mud filtrate invasion.


Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Peng Xu ◽  
Mingbiao Xu

Oil-based drilling fluids (OBDFs) have a strong wellbore stabilization effect, but little attention has been paid to the formation damage caused by oil-based drilling fluids based on traditional knowledge, which is a problem that must be solved prior to the application of oil-based drilling fluid. For ultradeep fractured tight sandstone gas reservoirs, the reservoir damage caused by oil-based drilling fluids is worthy of additional research. In this paper, the potential damage factors of oil-based drilling fluids and fractured tight sandstone formations are analyzed theoretically and experimentally. The damage mechanism of oil-based drilling fluids for fractured tight sandstone gas reservoirs is analyzed based on the characteristics of multiphase fluids in seepage channels, the physical and chemical changes of rocks, and the rheological stability of oil-based drilling fluids. Based on the damage mechanism of oil-based drilling fluids, the key problems that must be solved during the damage control of oil-based drilling fluids are analyzed, a detailed description of formation damage characteristics is made, and how to accurately and rapidly form plugging zones is addressed. This research on damage control can provide a reference for solving the damage problems caused by oil-based drilling fluids in fractured tight sandstone gas reservoirs.


2021 ◽  
Author(s):  
Oliver Czuprat ◽  
Kjetil Eriksen ◽  
Duncan Clinch ◽  
Piotr Byrski ◽  
Garbhan Gibbons ◽  
...  

Abstract Formation damage by the drill-in fluid has been identified as a major risk for the Dvalin HT gas field. To ensure the long-term stability and mobility of the mud even after an extended suspension time between drill-in and clean-up of the wells, a novel static aging test under downhole temperature and high pressure was conducted. Experiments have shown that the downhole stability is commonly underestimated when the surrounding pressure is lower than in the field. Thus, a high-pressure cylinder was used in vertical orientation in a heating oven with a pressure pump regulating the pressure up to 200 bar. The reservoir section was drilled with the optimized organo-clay-free oil-based drilling fluid (OCFOBDF) specified in the qualification phase. Tracers in the lower completion were used to identify clean-up from the upper high-permeability streak and the deeper (relatively lower) high-permeability streak. Due to extended wait on weather after drilling and completion of the first of the four wells, the lag time until clean-up was almost 11 weeks (74 days). It could be experimentally shown that the qualified OCFOBDF system weighted with micron sized barite remains mobile without phase separation even after static aging at 160 °C and 200 bar for the maximum estimated lag time between drilling and clean-up of 3 months. The absence of a gas cap in the set-up also better represents downhole conditions in the reservoir section and has shown that it improves the fluid´s stability. The clean-up of the well was successful with a maximum flowrate of 3.0 MM Sm3/d. Analysis of the tracers has proven that clean-up was successful for the entire reservoir section, including the deeper part. It could be concluded that in alignment with the lab tests that the mud fulfilled its requirement to be mobile even up to three months. Because of the superior properties, settling of solids (bridging and weighting material) could be avoided, resulting in no blockage of the (lower part of the) reservoir. The use HPHT aging has been the key to proving the long-term stability and mobility of the combined Drill-In and Completion Fluid. This technique falls outside of current API RP testing practices but is believed to be highly beneficial for qualification of fluids that will be left in the lower completion for long periods, especially in open hole completions under high temperature and pressure.


SPE Journal ◽  
2021 ◽  
pp. 1-22
Author(s):  
Sidharth Gautam ◽  
Chandan Guria ◽  
Laldeep Gope

Summary Determining the rheology of drilling fluid under subsurface conditions—that is, pressure &gt; 103.4 MPa (15,000 psi) and temperature &gt; 450 K (350°F)—is very important for safe and trouble-free drilling operations of high-pressure/high-temperature (HP/HT) wells. As the severity of HP/HT wells increases, it is challenging to measure downhole rheology accurately. In the absence of rheology measurement tools under HP/HT conditions, it is essential to develop an accurate rheological model under extreme conditions. In this study, temperature- and pressure-dependence rheology of drilling fluids [i.e., shear viscosity, apparent viscosity (AV), and plastic viscosity (PV)] are predicted at HP/HT conditions using the fundamental momentum transport mechanism (i.e., kinetic theory) of liquids. Drilling fluid properties (e.g., density, thermal decomposition temperature, and isothermal compressibility), and Fann® 35 Viscometer (Fann Instrument Corporation, Houston, USA) readings at surface conditions, are the only input parameters for the proposed HP/HT shear viscosity model. The proposed model has been tested using 26 different types of HP/HT drilling fluids, including water, formate, oil, and synthetic oil as base fluids. The detailed error and the sensitivity analysis have been performed to demonstrate the accuracy of the proposed model and yield comparative results. The proposed model is quite simple and may be applied to accurately predict the rheology of numerous drilling fluids. In the absence of subsurface rheology under HP/HT conditions, the proposed viscosity model may be used as a reliable soft-sensor tool for the online monitoring and control of rheology under downhole conditions while drilling HP/HT wells.


2008 ◽  
Author(s):  
Prasad B. Kerkar ◽  
Shirish Liladhar Patil ◽  
Godwin Amajuoyi Chukwu ◽  
Abhijit Yeshwant Dandekar ◽  
Santanu Khataniar

1999 ◽  
Vol 121 (3) ◽  
pp. 149-153 ◽  
Author(s):  
U. A. Tare ◽  
N. E. Takach ◽  
S. Z. Miska ◽  
F. B. Growcock ◽  
N. Davis

This work discusses the effect of incorporating blast furnace slag (BFS) as an additive in water-based drilling fluids. The intent of this treatment is rapid development of a thin, impervious, and easily removable filter cake, thereby minimizing detrimental impact of the drilling fluid on formation productivity as opposed to previous applications of BFS in universal fluids. To evaluate the impact of BFS on filter cake properties, permeability plugging apparatus (PPA) tests and dynamic formation damage (DFD) studies were conducted. Drill-in fluids and dispersed muds were tested using varying quantities of BFS. Once a steady rate of dynamic filter cake deposition was achieved, the BFS in the filter cakes was chemically activated. The results obtained from these activation studies were compared with those obtained with no BFS and with unactivated BFS. The nature of the filter cakes was examined with an environmental scanning electron microscope (ESEM). Results obtained from the PPA tests indicate substantial decreases in initial spurt loss and filtrate volume with increasing concentration of BFS. The DFD studies substantiate the aforementioned observations and show enhancement of return permeabilities with BFS activation. ESEM studies demonstrate that BFS can consolidate filter cakes.


Author(s):  
Winarto S. ◽  
Sugiatmo Kasmungin

<em>In the process of drilling for oil and gas wells the use of appropriate drilling mud can reduce the negative impacts during ongoing drilling and post-drilling operations (production). In general, one of the drilling muds that are often used is conventional mud type with weighting agent barite, but the use of this type of mud often results in skin that is difficult to clean. Therefore in this laboratory research an experiment was carried out using a CaCO3 weigting agent called Mud DS-01. CaCO3 is widely used as a material for Lost Circulation Material so that it is expected that using CaCO3 mud will have little effect on formation damage or at least easily cleaned by acidizing. The aim of this research is to obtain a formula of mud with CaCO3 which at least gives formation damage. Laboratory experiments on this drilling mud using several mud samples adjusted to the property specifications of the mud program. Mud sample consists of 4, namely using super fine, fine, medium, and conventional CaCO3. First measuring mud properties in each sample then testing the filter cake breaker, testing the initial flow rate using 200 ml of distilled water and a 20 micron filter disk inserted in a 500 ml HPHT cell then assembled in a PPA jacket and injecting a pressure of 100 psi. The acidification test was then performed using 15% HCL and then pressured 100 psi for 3 hours to let the acid work to remove the cake attached to the filter disk (acidizing). Laboratory studies are expected which of these samples will minimize the formation damage caused by drilling fluids.</em>


2013 ◽  
Vol 748 ◽  
pp. 1273-1276 ◽  
Author(s):  
Ben Guang Guo ◽  
Li Hui Zheng ◽  
Shang Zhi Meng ◽  
Zhi Heng Zhang

The fuzzy ball drilling fluids have been developed on the basis of the circulation foam and Aphron to control lost circulation effectively. There are some difficulties in drilling U-type well, such as well-bore stability, cutting carrying problem, large torque and friction at the horizontal section, and formation damage to coal-bed. The objective of this paper was to show some applications of fuzzy ball drilling fluids on U-type wells of the Ordos Basin and prove the superiority of fuzzy ball drilling fluid in CBM drilling. To the three mentioned cases, the density of fuzzy ball drilling fluid was 0.90~1.18g/cm3, the funnel viscosity was 45~72s, the dynamic shear force was 12~19 Pa, the PV was 13~19mPa·s and the pH was ranged from 7 to 9. To use the fuzzy ball drilling fluids, the average ROP increased above 10% with no borehole complexity, such as stuck pipe, hole enlargement causing poor cleaning and etc. These cases reflected excellent properties of the fuzzy ball drilling fluids including effectively sealing, good carrying and suspension ability, formation damage control and compatible weighted by inert materials. Furthermore, the fuzzy ball drilling fluids will not affect BHA tools like motors and MWD in CBM drilling.


SPE Journal ◽  
2020 ◽  
Vol 25 (03) ◽  
pp. 1333-1350 ◽  
Author(s):  
Sidharth Gautam ◽  
Chandan Guria

Summary Viscoelasticity plays a significant role in improving the performance of the drilling fluid by manipulating its elastic properties. An appropriate value of the first normal stress difference (N1), extensional viscosity (ηe), and relaxation time (θ) enhance the cutting transportability, hole-cleaning ability, filtration loss, and lubrication behavior. However, the performance of the drilling fluid deteriorates during the drilling of high-pressure and high-temperature (HPHT) wells under acid gas and salt(s) contamination. Therefore, it is a challenging task to synthesize a thermally and rheologically stable drilling fluid, which is acid as well as salt(s) resistant, and maintain its desired properties. Although several water-soluble synthetic polymer-based drilling fluids have been used widely for the drilling of HPHT wells, most of these are limited at less than 200°C. Polyanionic cellulose (PAC) has an excellent heat-resistant stability, salt tolerance, calcium and magnesium resistant, and strong antibacterial activity, and it exhibits exceptional filtration and rheological behavior under HPHT conditions. However, using PAC beyond 200°C is limited because of the presence of the biodegradable cellulose units in it. To use the extraordinary properties of PAC, it is aimed to increase the thermal stability of PAC through appropriate modification. In this study, PAC-grafted copolymers involving acrylamide (a salt-tolerant viscosifying agent), 2-acrylamide-2-methyl-1-propane sulfonic acid (a thermally stable lubricating and fluid-loss control agent), and sodium 4-styrene sulfonate (a high-temperature deflocculant) is synthesized optimally through maximizing the thermal degradation stability of the grafted copolymer and minimizing the filtration loss as well as the coefficient of friction (CoF) of the drilling fluid simultaneously. Optimally synthesized PAC-grafted copolymers are then used to prepare water-based mud (WBM) involving American Petroleum Institute (API)-grade bentonite and alpha-glycol functionalized nano fly ash, and the tests for steady shear viscosity and viscoelasticity are performed to determine the rheological stability of mud beyond 200°C. The amplitude sweep tests for viscoelasticity are performed to determine the linear viscoelasticity range (LVR), structural stability, gel strength, and dynamic yield point (YP), whereas frequency, time, and temperature sweep tests are performed to obtain the elastic modulus (G′), viscous modulus (G″), and complex viscosity under HPHT conditions to check the stability of the drilling fluids under different holding times. Dynamic and static aging tests of the developed drilling fluids are performed at elevated temperature and pressure, and the aged muds are tested by evaluating the rheology, frictional, and filtration-loss behavior as per the API recommended procedure. The stability of the aged muds is also tested by evaluating the N1, ηe, and θ using a cone and plate rheometer. The performance of the proposed drilling fluids is also tested under acidic, sodium chloride (NaCl), and calcium chloride (CaCl2) environments at HPHT bottomhole conditions. The experimental results under HPHT conditions reveal that the performance of the mud (i.e., thermal stability, cutting transportability, hole-cleaning ability, filtration loss, and lubrication behavior) could be considerably improved by increasing the elastic properties of the drilling fluid by manipulating the molecular weight of the proposed PAC-grafted copolymer. Finally, the environmental effect of the developed muds is evaluated by finding the lethal concentration that kills 50% of the shrimp population (i.e., LC50) and the Hg and Cd contamination, and they are found to be environmentally safe.


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