Intelligent Well Drainage and Interference Density Analysis Tool for Optimizing Infill Drilling

During the progressive development of mature fields, it is imperative to drill many infill wells to accelerate production and access bypassed oil. Optimizing the infill well spacing is always the concern to reduce interference with existing wells and improve recovery. In the present study, using intelligent data mining techniques, a new analysis and visualization tool has been developed and implemented to estimate and map drainage radius by well to assess the efficiency of the current development pattern and properly plan future wells. The tool deployed several performance-based techniques to estimate the contacted stock-tank oil initially in place (STOIIP) by each existing well, and outcomes can be compared between techniques for validation. The contacted STOIIP is then converted into an effective drainage radius by well using reservoir properties from the geo-cellular model. The evaluated reservoir is subdivided vertically into pay zones drained by the wells based on geological barriers/baffles to flow and connectivity across the zones. The tool estimates drainage radii of the wells produced from the reservoir using five different methods. The resultant Proved Developed Producing (PDP) reserves polygon maps are generated for the connected zones. The drainage radii of wells with behind-casing opportunities are estimated based on correlation and adjacent wells methods, and Proved Developed Non-Producing (PDNP) reserves polygon maps were generated. Well interference density is estimated based on overlapping drainage radii polygons with adjacent well locations, which has then been validated with production and pressure data from the wells. This paper describes the methodology by which the well drainage radii and well interference density can be estimated and implemented on a selected reservoir. This workflow can be successfully used to identify drained and undrained areas around the wellbore and opportunities for additional infill wells in the various pay zones of the reservoir. This exercise observed consistency in the drainage radii cumulative distribution from decline curve analysis methods and the No-Further-Activities (NFA) simulation case.

Effect of drainage layers on water retention of potting media in containers.

Excess water retention in the potting medium is a significant problem for plants grown in containers due to the volume of saturated medium which forms above the drainage hole. Adding a layer of coarse material like gravel or sand at the bottom is a common practice among gardeners with the aim of improving drainage, but some researchers have argued that such layers will raise the saturated area and in fact worsen drainage. Two different depths and four different materials of drainage layer were tested with three different potting media to determine the water retention in the container after saturating and draining freely. For loamless organic media, almost all types of drainage layer reduced overall water retention in the container compared to controls. For loam-based media, most drainage layers had no effect on the overall water retention. Two simple models were also used to estimate the water retention in the media alone, excluding the drainage layer itself. All drainage layers reduced water retention of loamless organic media, according to both models. There was disagreement between the two models applied to loam-based media, and further study is required to determine the most accurate. Both models showed that some drainage layers with smaller particle sizes reduced water retention in loam-based media, but disagreed on the effect of drainage layers with larger particle sizes. Overall, any drainage layer was likely to reduce water retention of any medium, and almost never increased it. Thicker drainage layers were more effective than thinner layers, with the most effective substrate depending on the potting media used. A 60 mm layer of coarse sand was the most universally-effective drainage layer with all potting media tested.

Breaking Through the Boundary: Are HVFR and Landing Target The Solution? A Charlie Lake Exploitation Strategy

The objective of this exploitation strategy was to evaluate fracture-driven interactions (FDI) between intervals within the Braeburn members of the Lower Charlie Lake formation. With the primary goal to determine if a single well can be drilled in the Middle Braeburn and effectively drain reserves from two previously distinct producing intervals. The target intervals in this study were separated by a boundary layer composed of interbedded anhydrite, siltstone, and dolomite layers. Wells were completed in sequence using cemented ball-drop fracturing, and high-viscosity friction reducer (HVFR) fluid systems. Diagnostics including pressure monitoring, fracture modelling, and tracers were employed to evaluate stimulation response between wells. Realtime downhole pressure monitors observed the non-producing upper wellbore, while the lower well produced. Fluid rheology determined viscosity changes for different HVFR loadings, and fracture modelling assessed the impact of anhydrite on fracture height at different fluid viscosities. Proppant tracers injected in the lower well were logged in both wellbores observing propped communication between layers. Fluid and pressure diagnostics were used to monitor effective drainage between wells over time. During completion of the lower well, two (2) notable pressure communication events were observed in the offsetting upper well. Following the logging applications performed on both wellbores the results displayed three (3) localized points along the offsetting lateral. At which, a propped communication event was observed within a one (1) meter radius of investigation from the offsetting wellbore. The heel-most propped communication event in the offsetting wellbore was correlated to one of two (2) observed pressure communication events. The two (2) other instances of propped communication did not correspond with an observed pressure event. Following the logging application, the lower well was flowed back and put onto production. During this production period, the upper well remained shut in. Subsequent fluid diagnostic responses have indicated an increasing FDI response, facilitating the flow of hydrocarbon from the upper to the lower wellbore. This communication was primarily observed near the heel of both wellbores. Based on the results of the diagnostic tracers, the fracture model was updated to provide a development tool that would be more predictive for fracture height growth around thin anhydrites in the Charlie Lake formation. The technique of fracture stimulation through the anhydrite layer can be used to reduce the total number of wells required to effectively drain the formation.

Optimum Layout of Multiple Tree-type Boreholes in Low-Permeability Coal Seams to Improve Methane Drainage Performance

Extracting coal mine methane (CMM) is important for underground mining safety. The tree-type borehole drainage (TTBD) technique can effectively remove methane from coal seams. Determining a suitable drilling pattern for multiple tree-type boreholes will promote the efficient application of this technique in coal mines. Aimed at solving the problem that the optimum methane extraction layout for multiple tree-type boreholes is unclear, this study first constructed a full-coupled thermo-hydro-mechanical model to simulate methane flow in coal. This model and data from a coal mine were used to investigate the effect of multiple tree-type borehole layouts, tree-type borehole spacing, different Langmuir volume and different Langmuir pressure constants, and initial coal permeabilities on CMM drainage. The results show that the different tree-type borehole layouts result in significant differences in drainage and that the use of a rhombic sub-borehole layout can reduce the methane pre-drainage time by up to 44.4%. As the tree-type borehole spacing increases, the total time required for pre-drainage increases as a power function. As the Langmuir pressure constant, the fracture permeability, or the matrix permeability increases, the effective drainage zone expands. The effective drainage zone also expands when the Langmuir volume constant decreases but all these changes are accompanied by a shortening of the drainage completion time. These results can provide a reliable basis for optimizing tree-type borehole drilling layouts.

Aspiration or arthrotomy for paediatric septic arthritis of the shoulder and elbow: a systematic review

Upper extremity arthritis in children can be treated with joint aspiration, arthroscopy or arthrotomy, followed by antibiotics. The literature seems inconclusive with respect to the optimal drainage technique. Therefore, the objective of this systematic review was to identify the most effective drainage technique for septic arthritis of the upper extremity in children. Two independent investigators systematically searched the electronic MEDLINE, EMBASE and Cochrane databases for original articles that reported outcomes of aspiration, arthroscopy or arthrotomy for septic arthritis of the paediatric shoulder or elbow. Outcome parameters were clinical improvement, need for repetitive surgery or drainage, and complications. Out of 2428 articles, seven studies with a total of 171 patients treated by aspiration or arthrotomy were included in the systematic review. Five studies reported on shoulder septic arthritis, one study on elbow septic arthritis, and one study on both joints. All studies were retrospective, except for one randomized prospective study. No difference was found between type of treatment and radiological or clinical outcomes. Aspiration of the shoulder or elbow joint required an additional procedure in 44% of patients, while arthrotomy required 12% additional procedures. Conclusion: Both aspiration and arthrotomy can achieve good clinical results in children with septic arthritis of the shoulder or elbow joint. However, the scientific quality of the included studies is low. It seems that the first procedure can be aspiration and washout and start of intravenous antibiotics, knowing that aspiration may have a higher risk of additional drainage procedures. Cite this article: EFORT Open Rev 2021;6:651-657. DOI: 10.1302/2058-5241.6.200122

The Amplatzer device and pedicle muscle flap transposition for the treatment of bronchopleural fistula with chronic empyema after lobectomy: two case reports

Background Bronchopleural fistula (BPF) refers to an abnormal channel between the pleural space and the bronchial tree. It is a potentially fatal postoperative complication after pulmonary resection and a complex challenge for thoracic surgeons because many patients with BPF ultimately develop refractory empyema, which is difficult to manage and has a major impact on quality of life and survival. Therefore, an operative intervention combined with conservative and endoscopic therapies may be required to control infection completely, to occlude BPF, and to obliterate the empyema cavity during treatment periods. Case presentation Two patients who suffered from BPF complicated with chronic empyema after lobectomy were treated in other hospitals for a long time and did not recover. In our department, we performed staged surgery and creatively combined an Amplatzer Septal Occluder (ASO) device (AGA Medical Corp, Golden Valley, MN, USA) with pedicled muscle flap transposition. First, open-window thoracostomy (OWT), or effective drainage, was performed according to the degree of contamination in the empyema cavity after the local infection was controlled. Second, Amplatzer device implantation and pedicled muscle flap transposition was performed at the same time, which achieved the purpose of obliterating the infection, closing the fistula, and tamponading the residual cavity. The patients recovered without complications and were discharged with short hospitalization stays. Conclusions We believe that the union of the Amplatzer device and pedicle muscle flap transposition seems to be a safe and effective treatment for BPF with chronic empyema and can shorten the length of the related hospital stay.

INFILTRATION WELLS ALTERNATIVES TO REDUCE WATER PUDDLE IN LOWOKWARU DISTRICT, MALANG CITY

Surface waters give a plentiful supply of waters ready to be utilized for residence, farmland, fishery, industry, and electric generating machine, and most importantly, to deal with the problem of water scarcity (crisis). Rain is one of the hydrological cycles that help to preserve groundwater (shallow groundwater). During the rainy season, most waters go directly to the river and the sea without processing, creating inundations and flood in some places. Water resources, however, begin to lose their supporting capacity. Water supply is no longer balanced with the demand that starts to bulge up excessively. This disrupted balance is indicated by many critical lands that are less productive and incapable of absorbing waters to the ground. Considering this outline, the implementation of environmentally friendly infiltration wells can be a strategic option to solve the water balance issue. Some alternatives of infiltration wells are proposed as the solution to the problem that this research deals with. It is estimated that these wells can reduce 10%-15% of surface runoff rate in Lowokwaru District of Malang City, especially around Soekarno-Hatta Street that always leaves massive water puddle, especially during the rainy season. This research gives the relevant institutions and user community information about drainage construction, drainage network, and land use above drainage network. Through this information, it is expected that the follow-up can be given efficiently to produce an optimum and effective drainage network. Community participation, therefore, is needed to maintain the benefits of alternative infiltration wells to ensure their sustainability in the future.

Numerical simulation study on gas drainage by interval hydraulic flushing in coal seam working face

In order to solve the problem of difficult gas extraction in coal mine, a method of gas extraction from coal seam by interval hydraulic flushing is put forward. Based on the coal seam gas occurrence conditions of 7609 working face in Wuyang Coal Mine, the numerical simulation research on gas drainage by ordinary drilling and hydraulic flushing drilling was carried out by using COMSOL numerical simulation software. The results show that with the increase of hydraulic flushing coal quantity, the effective gas drainage radius also increases. The effective extraction radius of ordinary drilling is 0.5 m, and the effective extraction radius is 1.0 m, 1.2 m and 1.3 m respectively when the coal flushing quantity is 0.5t/m, 1.0t/m and 1.5t/m. As multiple boreholes are drained at the same time, the boreholes will affect each other, which will reduce the gas pressure and increase the effective drainage radius, the spacing between boreholes can be greater than twice the effective drainage radius of a single borehole when arranging boreholes. And the smaller the flushing interval, the more uniform the gas pressure reduction area. According to the numerical simulation results, the ordinary drilling and 1.0t/m interval hydraulic flushing test were carried out in the field. Through observation and analysis, the gas concentration of the interval hydraulic flushing drilling module was increased by 31.2% and the drainage purity was increased by 5.77 times compared with the ordinary drilling module. It shows that the interval hydraulic flushing drilling can effectively improve the gas drainage effect.

Influence of Deformation and Instability of Borehole on Gas Extraction in Deep Mining Soft Coal Seam

To study the effects of the three deformation instability modes of gas drainage borehole on gas drainage, the deformation instability mechanism of soft coal seams is analyzed, three deformation instability modes are proposed for soft coal seams, namely, complete holes, collapse holes, and plug holes, and a solid-fluid coupling model incorporating dynamic change of borehole suction pressure is established. The results of the study show the following. (1) When there is no borehole deformation (i.e., complete borehole), the suction pressure loss of drainage system in the borehole is very small, whose effect on gas drainage can be neglected. (2) In case of borehole collapse, the suction pressure loss is big at the collapse segment, and the total suction pressure loss of the drainage system in the borehole is bigger than that in the complete hole. However, it is smaller than the suction pressure of the drainage system and exerts limited effect on gas drainage. As the borehole collapse deteriorates, the effective drainage section of the borehole becomes smaller, while the suction pressure loss in the borehole increases continuously; thus, the gas drainage effect continuously worsens. (3) In case of plug hole, a continuous medium forms between the plug segment coal body and the surrounding coal seam, the plug segment drainage pressure turns into coal-bed gas pressure, and effective drainage length of the borehole shortens, seriously affecting the gas drainage effect. The study carries important theoretical guiding significance for improving gas drainage effect and effectively preventing gas disasters.

Study on Pre Pumping and Outburst Elimination Technology of “one hole and two elimination” in Bedding Directional Long Drilling

Aiming at the problem of gas control in the working face and the roadway to be excavated at the same time due to the small construction length of bedding borehole under the condition of the occurrence of soft coal, a technology of "one hole and two elimination" pre-drainage to eliminate gas outburst by using air screw motor drilling was put forward, and the field test was carried out in the 17102(3) working face of Pansu Coal Mine.The results show that this technology can effectively control the borehole trajectory, ensure the uniform and reasonable range of borehole outburst elimination, solve the problems of long gas treatment cycle caused by the construction of gas treatment roadway, improve the effective drainage time of borehole, ensure enough time and space for gas treatment, and be beneficial to the mining and replacement of mine.