Casing Deformation Mitigation Achieved Through Ball Activated Sliding Fracturing Sleeves – An Alternative to Plug and Perf Fracturing Operations

Casing Deformation has plagued numerous unconventional basins globally, in particular with plug-and-perforation (also known as plug-and-perf) operations. This infamous issue can greatly influence 20-30% of field productivity of horizontal wells in shale and tight oil fields (Jacobs, 2020). When a wellbore lies in a target zone and intersects many natural fractures, these fractures are perturbed by hydraulic stimulation. Therefore, rock or bedding slippage may occur, resulting in casing deformation. This phenomenon is escalated by active tectonics, high anisotropic in-situ stresses, and poor cement design. This paper evaluates the mechanisms of casing deformation. It reviews how these conditions can be evaluated in the target zone. The mitigation procedures to reduce casing deformation through either well planning or completions design are discussed. Finally, an alternative completion method to plug-and-perf allowing limited entry completion technique in restricted casing with a field case study will be discussed.

Evaluation of Source Rock Quality in Chang-7 Member of Major Oil Fields in Ordos Basin

Petroleum is an important natural resource for human. The demand for petroleum in the next several decades will continue to be high, which requires the exploitation of more petroleum sources. Chang-7 member of the Ordos basin is proven to be the richest among all members, and this research took a focus on making a comparison between the source rock quality of Chang-7 member in four major oil fields in the basin, to provide a simple view of priority oil fields for exploitation in the future. The research analyzed the source rock quality of four oil fields from the TOC, A%, rock type, R0, sedimentary environment, and kerogen type, and found a superiority of source rock quality of Maling and Zhidan oil field in multiple dimensions, mainly triggered by their sedimentary environment. The research concluded that the oil fields that was once in the central-southern region of the basin contains a slightly better source rock quality among the chosen fields, which is related to a more stable sedimentary environment in the early Triassic.

Methodological approaches to increasing the flooding system efficiency at the later stage of reservoir development

Based on the analysis of the efficiency of CVI.1 and CVI.2 oil reservoirs development, which partially coincide in structural terms, and the terrigenous strata of the Lower Carboniferous of one of Volga-Ural oil and gas province oil fields, an algorithm for assessing the efficiency of waterflooding was proposed, which takes into account the geological structure of the facility, the results of core and geophysical well surveys, as well as the historical performance of wells. The presented algorithm makes it possible to identify ineffective injection directions for making decisions on waterflooding system optimizing. The effect is the identified potential to cut costs by reducing inefficient injection, as well as identifying areas for the introduction of enhanced oil recovery techniques. Keywords: field development; reservoir pressure maintenance system; waterflooding efficiency; cost reduction.

Methodological approach to optimal geological and technological characteristics determining when planning hydraulic fracturing at multilayer facilities

The paper considers the issue of increasing the hydraulic fracturing efficiency in a multilayer facility at the final stage of development with an uneven degree of reserves development along the section. Based on the results of the analysis, it was found that the upper layers, which have the worst filtration-reservoir properties, are less developed in comparison with the highly productive lower ones. When hydraulic fracturing was carried out in the upper formations, some of the operations had low success due to the breakthrough of hydraulic fractures into the lower depleted formations. On the basis of the revealed dependencies, the work determined the optimal specific loading of proppant per meter of effective power, depending on the geological conditions, and maps of the prospects for hydraulic fracturing are built. Keywords: oil fields development; hydraulic fracturing; hydraulic fracturing optimization; multilayer facilities.

Stratigraphic Study for the Cretaceous-Tertiary period in Qasab-Jawan area in north weastern Iraq by using 2D seismic survey

A seismic study was conducted to re-interpret the Qasab and Jawan Oil fields in northwestern Iraq, south of the city of Mosul, by reprocessing many seismic sections of a number of field surveys by using the Petrel software. Two reflectors, represented by the Hartha formation, deposited during the Cretan age, and the Euphrates formation, formed during the Tertiary age, were delineated to stabilize the structural picture of these fields. The stratigraphic study showed that the Qasab and Jawan fields represent areas of hydrocarbon accumulation. Seismic attribute analysis showed low values of instantaneous frequency in the areas of hydrocarbon accumulation. Instantaneous phase was used to determine the limits of the sequence, the nature of sedimentation, and the type of vanishing, i.e. onlap vs. toplap. Low instantaneous amplitude values were recorded, indicating hydrocarbon reservoirs in the studied area. Various other seismic stratigraphic features were studied , including the distribution mound, flat spot, and channels in the two formations, but they were discontinuous because of the tectonic effects. These activities explain reasonably the distribution of hydrocarbons in the studied area.

Expanding the amount of preferential royalty facilities with hard-to-recover oil reserves

The article deals with the economic attractiveness of hard-to-recover oil reserves in the Ural-Volga region development. The fuel and energy complex is a budgetforming one for oil-producing regions and contributes to the development of all sectors of the economy, and is bound by social responsibility. The current situation and trends in the global economy demonstrate that oil production intensification is a paramount task to all related industries efficiency improving, taxes being the main share in the cost structure. Therefore, in order to stimulate the reserves from low-permeability reservoirs development, tax exemptions are provided in the form of a reduced tax on mineral extraction. The paper considers an example of development efficiency improving due to tax incentives. According to the assessment results, the option with tax incentives is more beneficial for both the state and the subsoil user. Keywords: oil fields development; hard-to-recover reserves; taxation; qualified for tax relief; production intensification.

Improving the carbonate reservoirs development efficiency on the example of the Tournaisian stage deposits

The article deals with the issue of carbonate strata of complex geological structure development efficiency improving. Such facilities, as a rule, have deteriorated reservoir properties, parameter anisotropy and are complicated by secondary cavernosity. All of these factors affect the recovery efficiency and are often reflected in development indicators. On the example of Tournaisian stage deposits an example of a methodological approach to the development analysis which takes into consideration various geological factors is presented. As a result, various dependencies were obtained, which when taken into account determin the most promising areas in terms of development efficiency. The issues of the waterflooding system efficiency and the ways of its efficiency increasing are considered separately. Keywords: oil fields development; carbonate reservoirs; development efficiency; waterflooding system.

Methodological approach to the resource base efficiency monitoring in oil fields development

The article discusses the issue of resource base management in a complex structure of residual reserves. To increase the efficiency of the reserves development, constant monitoring of their distribution is necessary - how much they are involved, is there any potential for additional involvement, how efficient are the areas already involved in development. The paper proposes a methodological approach to the residual reserves control process organization, which allows planning and adjusting the program of reserves development. This is of particular relevance for companies that develop assets in the late stages of development, which do not have the ability to indiscriminate drilling. On the example of one of the enterprises developing assets in the Volga-Ural oil and gas province, the structuring of residual reserves was carried out, on the basis of which a strategy for increasing the reserves involvement in development was formed. To analyze the efficiency of reserves recovery in the involved areas, a reserve utilization factor based on the displacement forecast is proposed. Its implementation made it possible to identify problem areas, on the example of one of which a highly effective program for drilling horizontal wells was subsequently implemented. Keywords: oil fields development; oil reserves; resource management; reserves development; horizontal wells.