Fracture, VUG and Intercrystalline Porosity and Permeability Analysis from Well Logs of LIRTIM Oil Field, Iraq

Carbonate reservoir unarguably contributes over 50% of presently produced crude oil in the world today especially from the middle-eastern part of the world with appreciable amount of reserve estimate yet unexplored. Deposition, sedimentation, diagenesis and other geological features of carbonate rocks has been studied leading their classification into: mudstone, wackestone, packstone, grainstone, boundstone and crystalline carbonate rocks. These are all characterised by various features such as fractures and vugs which influences its petro-physical behaviour. The study of the main features of carbonate reservoir using Archie’s cementation exponent “m” is an acceptable method of verifying the geological features in the reservoir which actually contribute to rock fluid properties and other production attributes of the reservoir. This was verified for some reservoir using well log values for Lirtim oil field in Iraq. The dominating geological features of the field were verified from a graphical representation of the different data from field reservoir. The reservoirs used as case studies in the research were also classified into different carbonate rocks using a graphical plot of their permeability against porosity values. This result gives a clue of the textural and grain size characteristics as well as the effective pore sizes of the reservoir. This method of analysis makes it easier to evaluate the post diagenetic strength of the reservoir rocks and fluid hosting capability in view of recovering hydrocarbon in the are

Formation Damage Removal Through Acidizing of an Oil Well After Drilling and Completion

This paper discusses a real case study on how formation damage can be removed after finishing all operations in drilling and completing a well that is used vertically for producing commercial hydrocarbons using Over Balanced Drilling (OBD) techniques. Formation damage happens in every drilled well during field operations. It is an undesirable and complicated situation usually caused by solids invasion, fines movements, organic precipitation and deposition, and collapse and swelling formations (clay formations). The production performance of drilled well is significantly affected by the scale of damage in the invaded formation of the pay zone. The process of finding ways to solve this problem and the mechanism of preventing formation damages are the most important efforts faced by oil and gas industries. Formation damage is even a difficult problem to diagnose, but there are still some steps used for indicating it. For instance, this includes; well testing, well history reports, and well logging analysis. However, these techniques can only carry out diagnosis and an overall measure of the damage. Also, the results can apply suitable mechanisms for minimizing the risks and reducing the causes. After drilling and completing a well in Field A in Kurdistan region-north of Iraq, acid job is performed for the well considering the other wells potential and productivity. This is because the level was not enough for oil to be delivered to degassing station with the request pressure as shown in the appendix figures of pressure versus depth and tables of surface well testing results. Acidizing is a mean of production optimization for naturally flowing wells, whereby a designed acid volume is pumped to remove the damaged interval. Hence, it aims to increase the flow of oil to the surface. The type of acid used was Hydrochloric acid (HCL) with a concentration of 15%. In choosing the acid concentration, historical stimulation operation and lab tests were considered as the field is been developed a long-time ago. Here, enough programming data were made available for proposing operation of which one of them is acidizing. In the mentioned Field A, wells with high pressure drop between the well that was shut in and flowing pressure are required to be stimulated through acidizing. In this case, the pressure difference was about 300 psig before performing the job. Thus, the aim of this job was to obtain the optimum pressure difference between Bottom hole flowing pressure ???????????? and Sand face well pressure ???????????? which yields to the maximum oil production rate. The objectives of the job were achieved after obtaining a high flow rate of 8000 bbl/day at the surface and from the slickline data measurement. This recorded too much lesser draw down pressure of 11 psig between ???????????? & ????????????

Performance Evaluation Of The New Natural And Environmentally Friendly Material For Lost Circulation Control At High Pressure And Hight Temperature

Lost circulation refers to the loss of a part or whole drilling fluid into the formation and is considered as one of the most challenges in drilling operations. It could be occurred either naturally in highly fractured formations or induced by excessive overbalance pressure which leads to crack and rupture the formations being drilling and thereby inducing the loss of the mud into them. There are a number of treatments for lost circulation and perhaps the using of lost circulation materials (LCMs) is one of the common treatments. LCM is any material that used as an additive in the drilling fluid to seal and plug the openings in the formations. LCM manufacturers are continually introducing hundreds of materials every year. Recently, many research and studies had been done and continue for developing and investigating natural LCMs as alternatives for the conventional LCMs. In this study, a pomegranate peel (PP) has been developed and evaluated to be used as a natural LCM. The main two advantages of the PP LCM over the conventional LCM are its cost and naturally friendly properties. A series of filtration tests has been conducted on various sizes and concentrations of PP in order to investigate the effects of the size and percent of the additive on lost control characteristics. Moreover, for the purpose of comparison, a number of filtration tests has been conducted for similar sizes and precents of one of the most used LCM, carbonate calcium. It has been observed that the filtrate rate for the reference mud was 32 ml/30 min. While, the optimum reduction of 81% of the filtrate has been gained by addition of 15 ppb of the fine sized (less than 75 microns) PP. Meanwhile, only 47% of the lost being control through the addition of 20 ppb of the fine sized carbonate calcium

Drilling Pipe Corrosion Reduction Using Natural, Biodegradable, and Environmentally Friendly Additive to the Drilling Fluid

Corrosion is one of the disasters attacking the drilling tools, particularly the drill pipes. Drilling fluid is the corrosive that increase the rate of corrosion in the pipes. In this study, it is intended to reduce the corrosivity of drilling fluid using a Prosopis farcta powder material. A natural, biodegradable, and environmentally friendly additive is added to the fluid in different particle sizes and amounts to obtain the lowest corrosion rate. Experiments are conducted in a well-like environment (high pressure high temperature filter press) over a wide range of parameters including pressure, temperature, and properties of the drilling fluid under dynamic conditions. The aim is to eliminate or reduce the corrosivity of the mud as well as to control the losses. The results showed a lower corrosion rate, 0.0029 mm/year, using P. farcta material in comparison with those obtained by researchers in the previous studies

Application of ultra-fine particles of potato as eco-friendly green additives for drilling a borehole: A filtration, rheological and morphological evaluation

Drilling fluid is crucial for oil and gas well drilling operations, serving key functions such as facilitating the removal of drill cuttings, maintaining borehole stability and controlling formation pressures. When the drilling fluid is lost into formations, it can alter the formation's integrity, contaminate groundwater and cause permeability damage. In addition, environmental concerns arise from the waste produced during drilling activities, particularly when discarded drilling fluids contain hazardous substances like heavy metals. This study explores the potential of integrating ultrafine potato powder (PP) into water-based drilling fluids (WBDFs) as environmentally friendly additives. Several analytical techniques including X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electronic microscope (SEM) and differential scanning calorimetry (DSC) were used to comprehensively characterize the prepared PPs. The study included API and HPHT filtration test, permeability plugging test and rheological evaluations of drilling fluids, assessing parameters such as filter loss, filter cake, apparent viscosity, plastic viscosity, yield point and gel strength under varied conditions of different particle sizes of PP, concentrations of PP, and temperature and pressure measurements. The obtaining results emphasize PP's potential to enhance the wellbore stability and reduce the fluid loss, the filtration of water or oil into the permeable formation, achieving 43% reduction in the filtration rate and 70% reduction in the filter cake thickness. Adding 0.5 wt% ultrafine PP improved the maximum gel strength to 32.2 lb/100 ft2, while the same concentration and particle size raised the plastic viscosity from 3 to 6.8 cP, which subsequently dropped to 6 cP in high temperature conditions. PP performed better compared with the reference fluid in improving the thinning behavior of the drilling fluids. Moreover, permeability plugging tests confirm that adding PP effectively lowered the filtration rate, with higher concentrations achieving greater reductions over time. These findings suggest that PP holds promise as an effective additive for drilling fluids, contributing to enhanced drilling efficiency, improved wellbore stability and a reduced likelihood of instability and lost circulation. The characterization and rheological analysis of PP biodegradable drilling fluids provide valuable insights for optimizing fluid formulations, tailoring them to specific operational conditions, and achieving a balance between fluidity, wellbore stability, and cuttings transport. This research highlights the potential of PP as a sustainable and efficient solution in the realm of drilling fluid additives

Application of ultra-fine particles of potato as eco-friendly green additives for drilling a borehole: A filtration, rheological and morphological evaluation

Drilling fluid is crucial for oil and gas well drilling operations, serving key functions such as facilitating the removal of drill cuttings, maintaining borehole stability and controlling formation pressures. When the drilling fluid is lost into formations, it can alter the formation's integrity, contaminate groundwater and cause permeability damage. In addition, environmental concerns arise from the waste produced during drilling activities, particularly when discarded drilling fluids contain hazardous substances like heavy metals. This study explores the potential of integrating ultrafine potato powder (PP) into water-based drilling fluids (WBDFs) as environmentally friendly additives. Several analytical techniques including X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electronic microscope (SEM) and differential scanning calorimetry (DSC) were used to comprehensively characterize the prepared PPs. The study included API and HPHT filtration test, permeability plugging test and rheological evaluations of drilling fluids, assessing parameters such as filter loss, filter cake, apparent viscosity, plastic viscosity, yield point and gel strength under varied conditions of different particle sizes of PP, concentrations of PP, and temperature and pressure measurements. The obtaining results emphasize PP's potential to enhance the wellbore stability and reduce the fluid loss, the filtration of water or oil into the permeable formation, achieving 43% reduction in the filtration rate and 70% reduction in the filter cake thickness. Adding 0.5 wt% ultrafine PP improved the maximum gel strength to 32.2 lb/100 ft2, while the same concentration and particle size raised the plastic viscosity from 3 to 6.8 cP, which subsequently dropped to 6 cP in high temperature conditions. PP performed better compared with the reference fluid in improving the thinning behavior of the drilling fluids. Moreover, permeability plugging tests confirm that adding PP effectively lowered the filtration rate, with higher concentrations achieving greater reductions over time. These findings suggest that PP holds promise as an effective additive for drilling fluids, contributing to enhanced drilling efficiency, improved wellbore stability and a reduced likelihood of instability and lost circulation. The characterization and rheological analysis of PP biodegradable drilling fluids provide valuable insights for optimizing fluid formulations, tailoring them to specific operational conditions, and achieving a balance between fluidity, wellbore stability, and cuttings transport. This research highlights the potential of PP as a sustainable and efficient solution in the realm of drilling fluid additives

Evaluation the effect of wheat nano-biopolymers on the rheological and filtration properties of the drilling fluid:Towards sustainable drilling process

Drilling fluid plays a crucial role in the drilling operation of the oil and gas wells by serving various functions including controlling formation pressures, preserving borehole stability, and removing drill cuttings. However, the loss of the drilling fluid into formations can lead to the permeability damage, groundwater contamination, and altered formation integrity. In addition, the waste generated from drilling activities poses environmental issues, particularly when drilling fluids containing substances, such as heavy metals are discarded. Water-based drilling fluids (WBDFs) are preferred due to their eco-friendliness and cost-effectiveness. However, they suffer from inadequate rheological and filtration properties, prompting the introduction of additives. This study evaluates the use of wheat grain as nano-biodegradable additives in WBDFs, focusing on different sizes of wheat powder ranging from nano to course particle size. Nano-biopolymers (WNBPs) were prepared from breaking down into the nanosized structure using the ball mailing approach and characterized using XRF, FTIR, TGA, DLS, SEM and TEM. Several drilling fluids including the reference, modified, biodegradable and nano-biodegradable drilling fluids were prepared from API SPEC 13A standard, carboxymethyl starch (CMS), wheat powder (WP) at 75–600 µm and nano-biopolymer (WNBPs), respectively. The formulated drilling fluids were investigated by conducting different measurements, such as pH, rheology, filtration and modeling. The obtained results show that the nano-biodegradable exhibited alkaline pH above 10 that keeps the drillpipe and equipment from the corrosion. The developed WNBPs exhibited a significant role in improving the rheological properties of the reference drilling fluid but not effective as CMS. The maximum gel strength of 957.6 pa was obtained from adding 2 wt% WNBPs and increased 1100 pa when temperature increased to 70 °C. Meanwhile, the same wheat nanoparticles enabled increasing the plastic viscosity from 0.03 to 0.09 pa.s and decreased to 0.07 pa.s under the influence of high temperature. In terms of the thinning behavior, the prepared wheat powders exhibited a significant role in providing the thinning behavior of the developed drilling fluids compared with the reference drilling fluid and CMS-modified drilling fluid. Adding 2 wt% WNBPs to the reference drilling fluid decreased the fluid loss from 19.5 to 14 mL but fine WPs have a stronger effective on the filtration properties and lowered the filtration rate to 11.5 mL.</p