Onshore Oil Wells Research Articles

A Novel Downhole Communication Strategy Using Loading Wave Conduction on Sucker-Rod Pumping System for Intelligent Lifting

Summary An effective and accurate downhole communication strategy is crucial for the fabrication of an intelligent lifting system for onshore oil wells. Traditional communication approaches based on the wired cable, acoustic wave, vibration wave, or fluid pressure are usually limited by downhole conditions, and issues such as cumbersome implementation, limited communication, and unstable signal modulation are encountered. Herein, a novel downhole communication strategy is proposed using the loading waves in the sucker-rod pumping system (SRPS). The loading wave is altered at the downhole pump at an extremely low frequency, and its significant variation could be captured by the surface load sensor. A controlled valve is installed between the chamber of the pump and the wellbore. The valve opening regulates the pressure in the pump chamber, leading to the generation of the controlled loading waves. The field tests are further carried out and prove the effective coding between the downhole and surface with an acceptable delay (~0.154 seconds for a well with a depth of 1000 m). For the loading wave transmission on the sucker-rod string system, the finite element method is used to solve the theoretical model considering the real circumstances, such as the coupling damping, centering device friction, and stuffing box friction. The impacts of operating parameters of the lifting system, wellbore conditions, and modulation of excitation signal on the communication process are systematically discussed. The transmission evaluation standard, applicable conditions, coding tactic, and potential engineering values are presented for the downhole communication system.

The effect of rotational speed on the performance of the electric submersible pump

The electric submersible pump (ESP) is a centrifugal pump with several stages. It's a dependable and efficient industrial lifting tool for lifting different amounts of fluids, and it's known for its adaptability and reliability. Electric submersible pumps are commonly used in onshore oil wells, as well as underground pumping and other applications. The pump's efficiency is evaluated under the control of various rotational speeds. The CFD approach is used in this analysis to analyze flow behaviors within the ESP at various flow speeds. ANSYS CFX program was approved to conduct and investigate single-stage simulation of the GN7000 pump. The sensitivity of the network was determined, and the best mesh for the solution was chosen. The flow field was solved using the (SST, Unsteady-RANS) model with different rotational velocities (2500-3000-3500 cycle in this case). The test used two fluids with varying viscosities, and the findings revealed that the viscosity has an impact on efficiency as well. There is a high level of compatibility as compared to previous studies. This research presented a set of curves for efficiency and pressure and to know the extent of the effect of rotational speed on performance in general

Development and implementation of device for capturing large mechanical particles falling into the space between cylinder and plunger of sucker-rod pump

The deep pump, mainly sucker-rod deep pumping method is widely applied in the onshore oil wells of Azerbaijan. Despite the fact that the deep-well sucker rod pumping method is widespread, its operation in sand-producing wells is accompanied by various complications. Since mechanical particles wearing the pump parts out, falling into the space between the plunger and the cylinder, either wedge the plunger inside the cylinder or increase the gap between them. To prevent the ingress of large particles of sand into the gap between the plunger and the cylinder of the deep sucker rod pump, a device for sand trapping has been developed. The sand-trapping device is installed within the well tubing strings on the rod string and prevents the big particles of the liquid in the pipes falling into the gap between the plunger and cylinder. As the plunger, the device is started via balanced head. Due to the equipment installation, the liquid injected from the pump undergoes pressure decrease and the conditions for deposition and accumulation of large particles are formed.

Bioremediation Enhances the Pollutant Removal Efficiency of Soil Vapor Extraction (SVE) in Treating Petroleum Drilling Waste

Contamination due to improper disposal of oilfield drilling waste is a serious environmental problem all over the world. This study used bench-scale experimental columns to investigate the effectiveness of combining soil vapor extraction (SVE) with bioremediation (bioaugmentation plus biostimulation) in treating drilling waste from onshore oil wells. The drilling waste used in this study was heavily contaminated with a total petroleum hydrocarbon (TPH) concentration of 2.5 × 104 mg/kg. After 154 h of SVE operation, the TPH concentrations decreased by 4.7–23.6 %, and continuous SVE operation did not significantly reduce the concentration of residual contaminants. Then, microbial consortium and inorganic nutrients (urea and K2HPO4) were employed further to enhance bioremediation, and after 216 h of bioremediation and SVE, 70 % of the residual TPH was removed. Bioremediation enhanced the overall pollutant removal efficiency by fully degrading low volatile compounds and transforming them into more volatile compounds which were extracted by SVE. Results from GC-MS analysis corroborated TPH concentration data showing the occurrence of biotransformation during SVE and bioremediation treatment. Overall, this study demonstrates that SVE combined with bioremediation is an effective technique for handling petroleum drilling waste.

Drivers to the workover rig problem

Abstract When onshore oil wells reduce the production due to a malfunction, workover rigs are used to restore productivity. Given a set of wells needing maintenance and a set of workover rigs, the workover rig problem (WRP) consists of finding rig routes for minimizing the total production loss of the wells within a finite time horizon. The wells have different loss rates and require different services such as cleaning, reinstatement and stimulation. The rigs can be at different positions in the oil field and can have different equipment. This problem shares some of the same characteristics of the vehicle routing problems. Using a literature review, we offer some new ways to consider and approach the problem in its actual context.

Geothermal energy from abandoned oil and gas wells using water in combination with a closed wellbore

Binary cycle power plants have been used successfully for electricity generation utilizing co-produced fluids from active onshore oil wells. Adapting this process for use on abandoned wells by circulating the binary working fluid down the wellbore has been previously proposed and a selection of fluids evaluated.This work proposes and evaluates an approach using water as the wellbore fluid in combination with abandoned wells and a closed wellbore. The wellbore is therefore used as a heat exchanger. The aim is to enable electricity generation via a binary cycle plant while mitigating contamination risks associated with the circulation of conventional organic working fluids. Well log data for over 2500 wells in Texas are used to assess the use of wellbores in this way and for calculation of geothermal gradient and surface temperature. Wellbore heat transfer and wellbore thermal resistance are calculated.With a geothermal gradient of 0.0311 °C/m, a fluid temperature of 130 °C is achieved using a wellbore depth of 4200 m and a mass flow rate of 2.5 kg/s. Flow rates up to 15 kg/s are shown using greater wellbore depth. Head loss and pumping requirements are calculated relative to wellbore depth with results finding maximum head loss and corresponding pump requirements remain small for the mass flow rates evaluated.Net power figures of 109 kW–630 kW are obtained utilizing a binary cycle power plant with a multistage heat exchanger. The use of abandoned wells as a means of generating electricity with water as the wellbore circulating fluid, utilising a method with no reliance on naturally occurring geothermal fluid is shown, offering a potential use for a global resource that is as yet unused.

Geothermal studies in oilfield districts of Eastern Margin of the Gulf of Suez, Egypt

Results of geothermal studies carried out at 149 onshore oil wells have been used in evaluation of temperature gradient and heat flow values of the eastern shore of the Gulf of Suez. The investigations included temperature logs in boreholes, calculation of amplitude temperature, geothermal gradients and heat flow. The results obtained indicate that geothermal gradient values are in the ranges of 0.02–0.044°C/m and regionally averaged mean heat flow values are found to fall in the interval of 45–120mW/m2. Temperature gradients and heat flow values change from low values eastward to high values toward the axial of Gulf of Suez rift. The result of this research work has been highly successful in identifying new geothermal resources eastward of the Gulf of Suez. Additionally, this study shows that the areas with relatively higher temperature gradients have lower oil window, mature earlier, than those with low gradient values. Thus, high temperature gradients cause to expedite the formation of oil at relatively shallow depths and narrow oil windows. On the other hand, low temperature gradient makes the oil window to be quite broad when locate at high depths.

A new diagnostic method for identifying working conditions of submersible reciprocating pumping systems

The submersible pumping unit is a new type of pumping system for lifting formation fluids from onshore oil wells, and the identification of its working condition has an important influence on oil production. In this paper we proposed a diagnostic method for identifying the working condition of the submersible pumping system. Based on analyzing the working principle of the pumping unit and the pump structure, different characteristics in loading and unloading processes of the submersible linear motor were obtained at different working conditions. The characteristic quantities were extracted from operation data of the submersible linear motor. A diagnostic model based on the support vector machine (SVM) method was proposed for identifying the working condition of the submersible pumping unit, where the inputs of the SVM classifier were the characteristic quantities. The performance and the misjudgment rate of this method were analyzed and validated by the data acquired from an experimental simulation platform. The model proposed had an excellent performance in failure diagnosis of the submersible pumping system. The SVM classifier had higher diagnostic accuracy than the learning vector quantization (LVQ) classifier.

Producing Fluid Level Forecasting of A New Submersible Reciprocating Pump in Onshore Oil Wells

Producing Fluid Level Forecasting of A New Submersible Reciprocating Pump in Onshore Oil Wells

A simple and robust Simulated Annealing algorithm for scheduling workover rigs on onshore oil fields

Onshore oil wells are dependent of maintenance services such as cleaning, reinstatement and stimulation. These services can be performed by a limited number of workover rigs. Usually, wells need maintenance services and a scheduling of the workover rigs must be defined. This scheduling must consider some factors such as the well production, the type of service to be performed and time windows for the service. There is a production loss associated to wells waiting for maintenance services, so it is important to attend them as soon as possible. Thus, the workover rig scheduling problem consists of finding the best schedule for the limited number of workover rigs, minimizing the production loss associated with the wells waiting for maintenance service. We present a simple and robust Simulated Annealing (SA) algorithm for solving this problem. Computational results on real problems obtained in Brazil are reported and SA presents better solutions than all those approaches reported in the literature.

Environmental Impacts of Drilling Mud and Cutting Wastes from the Igbokoda Onshore Oil Wells, Southwestern Nigeria

The environmental impact of exploratory wastes (drilling muds&cuttings) generated during the drilling of Igbokoda X and Igbokoda Y onshore oil wells, was studied by analyzing its total hydrocarbon (TPH), aliphatic hydrocarbon (AH), polycyclic aromatic hydrocarbon (PAH) using gas chromatography-mass spectrophotometry (GC-MS) method and metal contents using atomic absorption spectrophotometry (AAS). The aim was to determine their toxicity and possible impacts on their immediate environments of disposal. These drilled wastes generated from the drilling of Igbokoda X and Igbokoda onshore wells indicated an exceedingly very high values of AH compared with the values of PAHs in both the oil based and water based muds and cuttings respectively. These values of aliphatic is generally >5000 mg/kg in all oil based sample types analyzed for the drilled muds and generally >4000 mg/kg in all the sample types analyzed for the drilled cuttings. However, these values of the AH varied according to sample types with the water based drilled mud collected at the depth of 4121-10171 feet having values of >6000 mg/kg while the value in the water based drilled cuttings is generally <5000 mg/kg. Both the oil based drilled mud and cuttings have higher values of PAHs at the drilled samples collected between 0-4121 feet than deeper depth and composite samples. Iron (Fe) has the highest concentration followed by calcium (Ca), magnesium (Mg) with varying level of toxic metals like lead (Pb), Nickel (Ni), Manganese (Mn) and Chromium (Cr) in both the oil and water based drilled mud and cuttings from Igbokoba X and Igbokoba Y wells. Most of the analyzed parameters (AH, PAHs, TPH) and metals like Pb, Mn, Cr, etc. generally have values higher than that of the United States Environmental Protection Agency, Federal Environmental Protection Agency and Directorate of Petroleum Resources Standards in some cases thereby implying possible negative impacts on the immediate environments.

A Grasp with Path-Relinking for the Workover Rig Scheduling Problem

Onshore oil wells depend on special services like cleaning, reinstatement and stimulation. These services, which are performed by a short number of workover rigs, are important to keep oil production as optimum as possible. Consequently, scheduling must be determined, where several factors interfere, such as production, service to be performed on each well, and time windows for each service. When a well needs service, its production is interrupted. In this regard, the workover rig scheduling problem consists of finding the best sequence of wells, which minimizes the production loss associated with the wells waiting for maintenance. In this paper, the authors present a Greedy Randomized Adaptive Search Procedure (GRASP) with Path-Relinking (PR) to solve this problem. Computational results are obtained from real problems of a Brazilian oil field.

Environmental impacts of drilling mud and cutting wastes from the Igbokoda onshore oil wells, Southwestern Nigeria

The environmental impact of exploratory wastes (drilling muds & cuttings) generated during the drilling of Igbokoda X and Igbokoda Y onshore oil wells, was studied by analyzing its total hydrocarbon (TPH), aliphatic hydrocarbon (AH), polycyclic aromatic hydrocarbon (PAH) using gas chromatography-mass spectrophotometry (GC-MS) method and metal contents using atomic absorption spectrophotometry (AAS). The aim was to determine their toxicity and possible impacts on their immediate environments of disposal. These drilled wastes generated from the drilling of Igbokoda X and Igbokoda onshore wells indicated an exceedingly very high values of AH compared with the values of PAHs in both the oil based and water based muds and cuttings respectively. These values of aliphatic is generally >5000 mg/kg in all oil based sample types analyzed for the drilled muds and generally >4000 mg/kg in all the sample types analyzed for the drilled cuttings. However, these values of the AH varied according to sample types with the water based drilled mud collected at the depth of 4121-10171 feet having values of >6000 mg/kg while the value in the water based drilled cuttings is generally

New Concept for Lifting in Onshore Oil Wells

This paper presents the development of a prototype of a tubular linear induction motor applied to onshore oil exploitation, named MATAEligOS (which is the Portuguese acronym for Tubular Asynchronous Motor for Onshore Oil Exploitation). The function of this motor is to directly drive the sucker-rod pump installed in the down hole of the oil well. Considering the drawbacks and operational costs of the conventional oil extraction method, which is based on the walking beam and rod string system, the developed prototype is intended to become a feasible alternative from both technical and economic points of view. At the present time, the MATAEligOS prototype is installed in a test bench at the Applied Electromagnetism Laboratory at the Escola Politecnica da Universidade de Sao Paulo. The complete testing system is controlled and supervised by special software, enabling good flexibility in operation, data acquisition, and performance analysis. The test results indicate that the motor develops a constant lift force along the pumping cycle, as shown by the measured dynamometric charts. Also, the evaluated electromechanical performance seems to be superior to that obtained by the traditional method. The system utilizing the MATAEligOS prototype allows the complete elimination of the rod string sets required by the conventional equipment, indicating that the new system may advantageously replace the surface mechanical components presently utilized.