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The Iraqi government has agreed to buy out ExxonMobil's 32.7% stake in the southern West Qurna 1 oil field, with state-owned Basra Oil Company acquiring the largest share in what is touted as one of the world's largest oil fields with recoverable reserves estimated to exceed 20 billion bbl. Iraq's Oil Minister and head of Iraq's OPEC delegation, Ihsan Abdul Jabbar announced the government's final investment decision to buy out Exxon during an event on 19 June in Baghdad marking the 60th anniversary of OPEC's founding. Iraq's oil ministry had asked formally to buy ExxonMobil's West Qurna 1 shares in May 2021 after the supermajor failed to win the government's approval of an agreement it made the previous January to sell its 32.7% to third parties. Among the parties was PetroChina which already held a 32.7% share. ExxonMobil was reportedly asking $350 million for the stake, according to the UK-based Arabic news service Shafaq.
Yang, Xuewen (PetroChina Tarim Oilfield Company) | Liu, Hongtao (PetroChina Tarim Oilfield Company) | Ao, Kangwei (CNPC Tianjin Boxing Engineering Science & Technology Co., Ltd) | Yang, Lei (CNPC Tianjin Boxing Engineering Science & Technology Co., Ltd) | Zhang, Tianyi (CNPC Tianjin Boxing Engineering Science & Technology Co., Ltd) | Tu, Siqi (CNPC Tianjin Boxing Engineering Science & Technology Co., Ltd) | Xin, Haipeng (CNPC Tianjin Boxing Engineering Science & Technology Co., Ltd) | Yuan, Zhongtao (PetroChina Tarim Oilfield Company)
ABSTRACT The comb-type salt-resistant polycarboxylate dispersant (CSPD) was developed to solve the shortcomings of the poor dispersibility of the current dispersant in saline cement slurry. CSPD has salt-to-saturation resistance, poor thixotropy, and the use in saturated saline water prepared slurry can still meet the requirements of the standard for dispersant in freshwater systems. It can effectively disperse salt-containing high-density cement slurry, conventional density and low-density cement slurry. CSPD has successfully solved the problem that the slurry cannot be prepared and cannot be constructed due to the rapid hydration of the saline slurry which was prepared with NaCl in the high-temperature environment. It also solved the core problem in the nano-based low-density cement slurry. Besides the application in anti-channeling cement slurry led to good dispersion performance. It has been successfully applied in Halfaya Oilfield, Missan Oilfield, Dagang Oilfield and Tarim Oilfield, effectively improving the fluidity of cement slurry, ensuring the displacement efficiency, improving the cementing quality, and ensuring the cement ring sealing ability. INTRODUCTION During the drilling process, complex formations such as high-pressure saline formations, large salt paste formations, or water-sensitive formations were encountered (Chang, 2013; Gao, 2014; Hou, 2013; Wei, 2014) both in China and overseas in Iraq, Kazakhstan, Uzbekistan, Indonesia and other countries (Chen, 2015; Gai, 2011; Zhou, 2011; Zou, 2015). In addition, in sea and coast operations, it is often attempted to directly prepare cement slurry with seawater (Chen, 2013; Lu, 2014). Due to the high solid content and high salt content, salt/seawater cement slurry exhibits poor fluidity, strong thixotropy and high initial consistency. Comb-type polycarboxylate dispersant is a kind of high performance dispersant which is used to help modify slurry rheology for easier mixing and placement. Rheology is a measure of both the resistance to flow and a reduction in the resistance to flow under pressure. Adding comb-type polycarboxylate dispersant can reduce friction and pressure during pumping, enhance turbulent flow with reduced pumping rate, and allow operators to mix densified cement slurries. Comb-type polycarboxylate dispersant can also be used to reduce the pressure exerted when cement passes through unconsolidated sands, depleted or weak formations, which may prevent leakage circulation.
Student Chapter Excellence Award Akademi Minyak dan Gas Balongan Alexandria University Almetyevsk State Oil Institute American University of Ras Al Khaimah Anambra State University Azerbaijan State Oil and Industry University Baku Higher Oil School Bandung Institute of Technology Batman University Bayero University, Kano Beirut Arab University China University of Petroleum (East China) Colorado School of Mines Curtin University Dawood Univ. of Engineering & Technology, Karachi Dibrugarh University Enugu State University Escuela Superior Politecnica del Litoral Faculdades Metropolitanas Unidas Federal University of Alagoas Federal University of Sergipe Federal University of Technology Owerri Federal University of Technology, Akure Future University in Egypt Gubkin University Igbinedion University Okada Indian Institute of Technology (ISM), Dhanbad Institut Teknologi Kalimantan Institut Teknologi Sepuluh Nopember (ITS) Islamic University of Riau Kuwait University Lebanese American University Louisiana State University Mit-World Peace University Montana Tech Nile University of Nigeria Nkumba University Pennsylvania State University Politeknik Energi dan Mineral (PEM) Akamigas Saint Petersburg Mining University Stanford U The American University of Iraq, Sulaimani The University of Trinidad & Tobago UCSI University Ukhta State Technical University Universidad Central del Ecuador Universidad del Zulia Universidad Privada de Santa Cruz, Bolivia Universidad San Francisco Xavier Universidade Federal de Campina Grande Universidade Federal de Pelotas Universidade Federal do Espirito Santo Universidade Federal do Rio de Janeiro Universidade Federal do Rio Grande do Norte Universiti Teknologi Malaysia Universiti Teknologi MARA (UiTM) Universiti Teknologi Petronas University of Batna 2 University of Bucharest University of Clausthal University of Houston University of Indonesia University of Kurdistan, Hewler University of Nigeria University of Uyo
Summary Sand production is a serious problem in oil and gas wells, and one of the main concerns of production engineers. This problem can damage downhole equipment and surface production facilities. This study presents a sand production case and quantifies sanding risks for an oil field in Iraq. The study applies an integrated workflow of constructing 1D Mechanical Earth Modeling (MEM) and predicting the sand production with multiple criteria such as shear failure during drilling, B index, and critical bottomhole pressure (CBHP) or critical drawdown pressure (CDDP). Wireline log data were used to estimate the mechanical properties of the formations in the field. The predicted sand production propensity was validated based on the sand production history in the field. The interpretation results of some wells anticipated in this study showed that when a shear failure occurs during drilling, the B index is around 2 × 10 MPa or less and the CBHP is equal to the formation pore pressure. For this case, sand control shall be carried out in the initial stage of production. On the other hand, when the shear failure does not exist, the B index is always greater than 2 × 10 MPa, and the CBHP is mostly less than the formation pore pressure. In this case, implementing sand control methods could be postponed as the reservoir pressure undergoes depletion. However, for the anticipated field, sand control is recommended to be carried out in the initial stage of well production even when the CBHP is less than the formation pore pressure since sanding will be inevitable when the reservoir pressure depletes to values close to the initial reservoir pressure. The tentative evaluation of the stress regime showed that a normal fault could be the stress regime for the formations. For a normal fault stress regime, the study explained that when the reservoir permeability is isotropic, an openhole vertical wellbore has less propensity for sand production than a horizontal wellbore. Moreover, when the wellbore azimuth is in the direction of the minimum horizontal stress, the CBHP will be lower than in any other azimuth, and sanding will take place at higher wellbore inclination angles. For the anticipated field, because of the casedhole well completion and the anisotropic reservoir permeability, a horizontal well drilled in the direction of minimum horizontal stress with oriented perforation in the direction of maximum horizontal stress is an alternative method for controlling sand production.
Abstract Multiple heritage wells in Iraq have experienced sulfur water corrosion impacting the intermediate and production casing strings; if left untreated, the wells could be lost. Typically, costly workover operations to address this issue requires running a tieback casing and cementing it to the surface to isolate the production path from the corrosive formation fluids. Thus, well integrity is regained, and corrosion to the well casing is prevented. To achieve long-term zonal isolation in corrosive environments, various slurry systems were studied, and a resin-blended cement system was selected to isolate the annulus between the tieback pipe and the outer intermediate casing. Reduced permeability of the set cement, resistance to fluid channeling, and increased shear bond strength, which protects the casing from H2S environments, are some of the salient features of this system. A premium grade external sleeve stage tool has been used for some of the strings to provide improved isolation. Details of the design methodology, laboratory testing, job execution, and results from various wells wherein this cement system was applied are discussed. Some of the cementing operations have differences in terms of execution, such as the use of single or multiple plug systems or use of a perforated joint or stage tool as a means of circulation. However, all operations used the resin cement system. All tieback casings were cemented with zero non-productive time (NPT) and passed a pressure integrity test. This resin-blend cement system's reliability has proven effective for isolating zones where corrosive fluids have created severe and recurring issues in the past. Therefore, this new approach has become the primary choice for the operator. A resin-blend cement system exhibits multiple desirable properties for isolation of the well's lifecycle and, if used as a primary option, can greatly reduce workover interventions in the future, leading to significant savings for the operator and increased well life, particularly in such corrosive environments.
Abstract Rock facies are typically identified either by core analysis to provide visually interpreted lithofacies, or determined indirectly based on suites of recorded well-log data, thereby generating electrofacies interpretations. Since the lithofacies cannot be obtained for all reservoir intervals, drilled section and/or wells, it is commonly essential to model the discrete lithofacies as a function of well-log data (electrofacies) to predict the poorly sampled or non-cored intervals. The process is called predictive lithofacies classification. In this study, measured discrete lithofacies distributions (based on core data) are comparatively modeled with well-log data using two tree-based ensemble algorithms: extreme gradient boosting (XGBoost) and adaptive boosting (AdaBoost) configured as classifiers. The predicted lithofacies are then combined with recorded well-log data for analysis by an XGBoost regression model to predict permeability. The input well-log variables are log porosity, gamma ray, water saturation, neutron porosity, deep resistivity, and bulk density. The data are derived from the Mishrif carbonate reservoir in a giant southern Iraqi oil field. For efficient lithofacies classification and permeability modelling, random sub-sampling cross-validation was applied to the well-log dataset to generate two subsets: training subset for model tuning; and testing subset for prediction of data points unseen during training of the model. Confusion matrices and the total correct percentage (TCP) of predictions are used to measure the prediction performance of each algorithm to identify the most realistic lithofacies classification. The TCPs for XGBoost and AdaBoost classifiers for the training subset were 98% and 100%, respectively. However, the TCPs achieved for the testing subsets were 97%, and 96%, respectively. The mismatch between the measured and predicted permeability from the XGBoost regressor was determined using root mean square error. The XGBoost model provides accurate lithofacies classification and permeability predictions of the cored data. The XGBoost model is therefore considered suitable for providing reliable predictions of lithofacies and permeability for the non-cored intervals of the same well and for non-cored wells in the studied reservoir. The workflow for lithofacies and permeability prediction was fully implemented and visualized using R open-source codes.
Al-Tammimi, Mohammad A. (Basrah University of Oil and Gas) | Al-Maliki, Sadeq Y. (Basrah Oil Company) | Alabody, Mustafa J. (Halliburton) | Al-Mudhafar, Watheq J. (Basrah Oil Company) | Wood, David A. (DWA Energy Limited) | Wojtanowicz, Andrew K. (Louisiana State University)
Abstract The Gas and Downhole Water Sink-Assisted Gravity Drainage (GDWS-AGD) process functions to enhance oil recovery by placing vertical gas injectors at the top of the reservoir combined with a series of horizontal wells located in the lower part of the reservoir for oil and water production. The injected gas accumulates to form or enhance a gas cap, while oil and water drain by gravity towards the base of the reservoir due to their heavier densities. To further enhance oil recovery, and to overcome the economic limitations of using vertical gas injectors, multi-completion production wells can also be used for gas injection through their annulus sections. This novel configuration thereby achieves Multi Completion-Gas and Downhole Water Sink-Assisted Gravity Drainage (MC-GDWS-AGD). The feasibility of MC-GDWS-AGD is investigated in this study by numerical simulation of the heterogeneous PUNQ-S3 reservoir, which is surrounded and supported by strong aquifers. The MC-GDWS-AGD process aims to minimize water cut in oil production wells from offshore reservoirs with bottom water drives and strong water coning tendencies. In the combined technologies, the gas is injected through the annulus of 7-inch production casings at the top of the reservoir. Then the same casing is dually completed for two 2-3/8 inch horizontal tubing strings: one above the oil-water contact for oil production, and one beneath that contact to function as the water sink. The two completions are hydraulically isolated within the wellbore by a packer. The lower (water sink) completion employs a submersible pump and water-drainage perforations. The submersible pump drains the accumulation of water from around the well. By doing so it prevents the water from breaking through into the oil column and adversely affecting production through the horizontal oil-producing perforations. The heterogeneous multilayered PUNQ-S3 reservoir, which is surrounded by infinite aquifers, was considered to simulate this process. The MC-GDWS-AGD process simulation is designed to evaluate oil flow rate, cumulative oil production, and water cut in oil production wells. The simulation compares the performance of MC-GDWS-AGD with the GAGD and GDWS-AGD completion configurations. The simulation results reveal similar performance for the MC-GDWS-AGD and GDWS-AGD configurations, for all the parameters considered. The GDWS-AGD method slightly outperforms the MC-GDWS-AGD method by achieving a small increase in cumulative oil production from 1.8x 10 m for the GAGD method to 1.83x 10 m. Both methods exceeded primary recovery in terms of cumulative oil production. Water cut decreased from 74% in the GAGD method to 63% in the MC-GDWS-AGD process. The oil recovery factor achieved by the MC-GDWS-AGD process increased by about 8% compared to that achieved by the GAGD method. The value of the MC-GDWS-AGD process is associated with its effectiveness to improve oil recovery by reducing the water coning, water cut, and improving gas injectivity, and at the same time reducing well costs. This new process allows for gas injection, oil, and water production to be conducted through a single multi-completed wellbore. This configuration also leads to multiple additional economic benefits, some of which are associated with the reduction of operational surface facilities in offshore oil fields.
The Iraqi Kurdistan territory is considered a unique region for the the petroleum geology, due to the fact that, on the one hand, part of the reservoirs, for example, of the Cenozoic age, was formed in relatively deep sea conditions, and was present with low-permeability deposits, mainly argillaceous limestones, where the role of fracturing in enhancing the reservoirs cannot be overestimated, and on the other hand, provide a wide opportunities for studying all elements of petroleum systems, including the reservoir. This study is focusing on a group of formations of significant economic interest to the oil industry in Iraq, namely the Lower Fars, Jeribe and Pilla Spi formations of the main Cenozoic (Tertiary) age. The above-mentioned formations are believed to play an important role in natural hydrocarbon systems. Some of them are good reservoirs and other ones are cap rocks. The availability of the very well exposed reservoir rocks on the outcrop provides a possibility to implement a wide range of fracture analysis and use the results to better predict natural fracture characteristics of subsurface fracture network of the Tertiary reservoirs in all Iraqi Kurdistan fields. One of the practical and very useful analysis is to use mathematical computation method within a frame of the MATLAB software. A modern method that did not well credited yet in the oil and gas industry. In this paper we utilize a photogrammetry technique in integration with mathematical computation to extract the full set of fracture characteristics from outcrop. Such Method is just started to get spotlight in the Oil and Gas Industry and expected to gain more attraction by researchers in soon future.
Abstract Cutting transportation is one of the most crucial drilling problems during penetrating shale formations juxtapose well stability events. It is equally important the drilling team should consider real time monitoring to the flow rate based on hole problem in the shale formation being drilled. Several authors have conducted extensive analysis to optimize the optimum flow rate in real time bases but the problem has not been fully understood especially when it comes for hole enlargement. Due to its simplicity, drilling engineers usually use deterministic method to control cutting transportation. The method adjusts drilling parameters such as pump flow rate (FR), plastic viscosity (PV), yield point (YP), Rate of penetration (ROP), revolution per minute (RPM), and mud weight (MW). The past practices of this method did not show significant improvements in well stability's events. This paper will introduce a numerical model to quantify the most sensitive hole cleaning parameters. For that purpose, the research will examine the real time modification of the drilling parameters based on rock fragments for sufficient hole cleaning. A tornado chart has been constructed based on hole enlargement considering hole cleaning, mud weight, elastic viscosity, yield point, ROP, RPM, and well angle. A Monte Carlo simulator has been utilized to reduce the uncertainty in hole enlargement during calculating the optimum parameters. 1000 trials have been fitted to the model based on the range of 0.5 to three times of hole enlargement. This method can articulate a huge impact on selecting drilling parameter based on the probabilistic evaluation. Drilling data from sixty wells in Southern Iraq have been investigated and they revealed a significant augment in none productive time because of the inappropriate selection of drilling parameters deteriorates well stability. This paper develops an engineering method to ensure sufficient lifting capacity to the rock cuttings while drilling an instable formations and it offer acceptable range of flow rate, yield point and elastic viscosity based on the severity of wellbore instability. The traditional wellbore stability is not panacea to wellbore problems without considering wellbore condition. Thus, a combination of all the interstice and extrinsic factors can be crucial in order to drill a well safely and cost effectively.