A Novel Approach for Near Wellbore Stimulation and Deposits Removal Utilizing Thermochemical Reaction

Organic and inorganic deposits play a major issue and concern in the wellbore of oil wells. This paper discusses the utilization of a new and novel approach utilizing a thermochemical recipe that shows a successful impact on both organic and inorganic deposits, as an elimination agent, and functions as stimulation fluid to improve the permeability of the near wellbore formation. The new recipe consists of mixing nitrite salt with sulfamic acid in the wellbore at the target zone. The product of this reaction includes heat, acidic salt, and nitrogen gas. The heat of the reaction is enough to liquefy the organic deposits, and the acidic salt will tackle the carbonate scale in the tube and will increase the permeability of the near wellbore area. The nitrogen gas is an inert gas; it will not affect the reaction and will help to flow back the well after the treatment. The experimental work shows an increment in the temperature by 65 °C when mixing the two chemicals. The test was conducted at room conditions and the temperature reached around 90 °C. Adding another 65 °C to the wellbore temperature is enough to melt asphaltene and wax, the acidic salt tackles carbonate scale. As a result, the mixture works on eliminating both the organic and inorganic deposits. The permeability of the limestone sample shows an increment of 65% when treated by the mixture of the reaction recipe. The uniqueness of the new thermochemical recipe is the potential of performing three objectives at the same time; the heat of the reaction removes the organic deposits in the wellbore, the acidic salt tackles carbonate scale, and improves the permeability of the near wellbore zone.

Analysis of strength property and pore characteristics of Taihang limestone using X-ray computed tomography at high temperatures

Rising temperature will cause the changes of pore characteristics and strength property in rock. This research takes the limestone produced in Taihang Mountains as the research object, and performs high-temperature treatment within 25–1000 °C. The high-resolution X-ray computed tomography (CT) scanning test method is used to visually reconstruct the three-dimensional image of the sample, and obtain the spatial distribution status of the mesoscopic parameters of the bones, pores/cracks, etc. The results show that when the temperature exceeded 700 °C, the samples appeared milky white in appearance and as the temperature increased, the color gradually turned white, macroscopic cracks began to appear on the surface, while the meso-pores connected rapidly, reflecting a typical progressive destruction process from inside to outside. The change law of volume porosity with temperature has a consistent trend with that of the apparent morphology of the sample. Similarly, the mechanical test results suggest that 700 °C is also the turning temperature for strength deterioration and brittle-plastic transformation of sample. Based on the results of high-temperature test, CT test and mechanical test, there are enough evidences to show that, for the limestone sample, 700 °C is probably to be the mutation temperature of physical–mechanical behavior.

Penentuan Senyawa Dan Pemodelan Suhu Pada Saat Pemanasan Batu Kapur Untuk Mendapatkan CaO Murni Dari Batu Kapur Papua

ABSTRACT Determination of compounds and temperature modeling during heating of limestone have been carried out to obtain pure CaO from Papua limestone. . The purpose of this research is to determine the compounds, morphology and characteristics of each element and molecule present in limestone from Papua and to simply model the optimum temperature to obtain CaO. From the results of XRF testing, there is one main element that contains the most chemical elements in the limestone sample from black soil (sample 1) and perumnas three (sample 2), namely Ca (calcium) with weight percent 99.57 and 99.69. XRD results are also supported from characterization with EDS where the dominant elements of sample 1 are O, Ca and Mg in sample 2 dominant elements Ca, O and C. Then based on SEM analysis, the morphology of CaMg (CO3) 2, Ca (Co3) and MgCa ( Co3) resembles a cube but the particle size is uneven and irregular due to impurities. The temperature obtained based on the results of this calculation is 12800C.

Depositional Environment and Petroleum System Analysis Based on Outcrop Analogue in Sukolilo Outcrop, Tuban Regency, East Java Province

The North East Java Basin has become one of the most promising basins in Indonesia. Over 150 million barrels of oil have been extracted from the Rembang Zone in the North East Java Basin. The Sukolilo outcrop, located in Sukolilo, Bancar, Tuban Regency, East Java, represents all the components of an exposed Middle Miocene petroleum system. The objective of this study is to present an excellent analogue for the depositional environment and petroleum system of the Middle Miocene formation of the Rembang Zone that can be expected in similar subsurface settings and as a tool for outcrop preservation with modelling using photogrammetry. Data consists of measured section, photogrammetry data, petrographic analysis, TOC content measurement and Rock-Eval Pyrolysis. Observed formation at this outcrop includes Ngrayong, Bulu, and Wonocolo Formation. The facies distributed in this outcrop consist of claystone-carbonaceous shale bedded, cross-bedded quartz sandstone, foraminiferal limestone and calcareous siltstone intercalated calcareous sandstone. Based on depositional environment analysis, the depositional environment changes from Lagoon – Tidal Flat – Shallow Marine – Shelf. The result of petrographic analysis shows that quartz sandstone porosity from the Ngrayong Formation can be identified as reservoir rock. Seal rock potential is shown by carbonate minerals diagenesis of the foraminiferal limestone sample. Source rock potential which is identified using TOC content and Rock-Eval Pyrolysis, reveals that the sample tends to be gas prone (kerogen type III) and has low thermal maturity (immature). Ductile deformation (conical anticline) and brittle deformation (normal fault) is predicted to be the migration path for this petroleum system.

A descriptive study of Syrian limestone and determining the optimal conditions for calcification and extinguishing

In this study, a descriptive study of Syrian limestone was conducted from the area of Al-Musallamiya-Aleppo. The optimal conditions for calcination of the limestone sample were studied. The results indicated that the preferred conditions for calcination were: crashing the limestone sample of diameter 5cm, the temperature of 1200°C, and the most suitable time was 60min. The optimal conditions for extinguishing the calcined limestone sample had also been identified As follows: Liquid phase ratio to the solid phase (L / S): (3: 1), Temperature 75°C, Time 30min. As a result of the experiments, two highly important products have been obtained in various industrial fields, namely calcium oxide and calcium hydroxide from local ore, which is widely available in large parts of the Syrian Arab Republic

A temperature- and stress-controlled failure criterion for ice-filled permafrost rock joints

Instability and failure of high mountain rock slopes have significantly increased since the 1990s coincident with climatic warming and are expected to rise further. Most of the observed failures in permafrost-affected rock walls are likely triggered by the mechanical destabilisation of warming bedrock permafrost including ice-filled joints. The failure of ice-filled rock joints has only been observed in a small number of experiments, often using concrete as a rock analogue. Here, we present a systematic study of the brittle shear failure of ice and rock–ice interfaces, simulating the accelerating phase of rock slope failure. For this, we performed 141 shearing experiments with rock–ice–rock “sandwich”' samples at constant strain rates (10−3 s−1) provoking ice fracturing, under normal stress conditions ranging from 100 to 800 kPa, representing 4–30 m of rock overburden, and at temperatures from −10 to −0.5 ∘C, typical for recent observed rock slope failures in alpine permafrost. To create close to natural but reproducible conditions, limestone sample surfaces were ground to international rock mechanical standard roughness. Acoustic emission (AE) was successfully applied to describe the fracturing behaviour, anticipating rock–ice failure as all failures are predated by an AE hit increase with peaks immediately prior to failure. We demonstrate that both the warming and unloading (i.e. reduced overburden) of ice-filled rock joints lead to a significant drop in shear resistance. With a temperature increase from −10 to −0.5 ∘C, the shear stress at failure reduces by 64 %–78 % for normal stresses of 100–400 kPa. At a given temperature, the shear resistance of rock–ice interfaces decreases with decreasing normal stress. This can lead to a self-enforced rock slope failure propagation: as soon as a first slab has detached, further slabs become unstable through progressive thermal propagation and possibly even faster by unloading. Here, we introduce a new Mohr–Coulomb failure criterion for ice-filled rock joints that is valid for joint surfaces, which we assume similar for all rock types, and which applies to temperatures from −8 to −0.5 ∘C and normal stresses from 100 to 400 kPa. It contains temperature-dependent friction and cohesion, which decrease by 12 % ∘C−1 and 10 % ∘C−1 respectively due to warming and it applies to temperature and stress conditions of more than 90 % of the recently documented accelerating failure phases in permafrost rock walls.

A temperature- and stress-controlled failure criterion for ice-filled permafrost rock joints

Instability and failure of permafrost-affected rock slopes have significantly increased coincident to warming in the last decades. Most of the observed failures in permafrost-affected rock walls are likely triggered by the mechanical destabilisation of warming bedrock permafrost including effects in ice-filled joints. The failure of ice-filled rock joints has only been observed in a small number of experiments, often using concrete as a rock analogue. Here, we present a systematic study of the brittle shear failure of ice and rock-ice interfaces, simulating the accelerating phase of rock slope failure. For this, we performed 141 shear experiments with rock-ice-rock sandwich samples at constant strain rates provoking ice fracturing (10−3 s−1), under relevant stress conditions ranging from 100 to 800 kPa, i.e. 4–30 m rock overburden, and at temperatures from −10 to −0.5 °C, typical for recent rock slope failures in alpine permafrost. To create close to natural but reproducible conditions, limestone sample surfaces were ground to international rock mechanical standard roughness. Acoustic emission (AE) was successfully applied to describe the fracturing behaviour, anticipating rock-ice failure as all failures are predated by an AE hit increase with peaks immediately prior to failure. We demonstrate that both, the warming and unloading (i.e. reduced overburden) of ice-filled rock joints lead to a significant drop in shear resistance. With a temperature increase from −10 °C to −0.5 °C, the shear stress at failure reduces by 64–78 % for normal stresses of 100–400 kPa. At a given temperature, the shear resistance of rock-ice interfaces decreases with decreasing normal stress. This can lead to a self-enforced rock slope failure propagation: as soon as a first slab has detached, further slabs become unstable through progressive thermal propagation and possibly even faster by unloading. Here, we introduce a new Mohr-Coulomb failure criterion for ice-filled rock joints that is valid for joint surfaces which we assume similar for all rock types, and which applies to temperatures from −8 to −0.5 °C and normal stresses from 100 to 400 kPa. It contains a temperature-dependent friction and cohesion which decrease by 12 %/°C and 10 %/°C respectively due to warming and it applies to temperature and stress conditions of more than 90 % of the recently documented accelerating failure phases in permafrost rock walls.