Modified Model for Shallow Soil Strength Recovery Calculation during Set-Up Periods of Jetted Conductor—A Case Study of Equatorial Guinea Bay Deep-Water Drilling

Jetted conductor setting depth is crucial for deep-water drilling. This paper presents an innovative method for determining the shallow soil resistance strength recovery factor based on the field data of Equatorial Guinea bay. It shows that the soil strength recovery factor of Equatorial Guinea bay is lower than that of the Gulf of Mexico. The conductor setting depth calculation referring to other place will have a high risk of wellhead sinking. According to the newly established designing charts, the conductor setting depth was recommended for the S1 well. Each preferred set-up period requires a specific setting depth. If the chosen set-up period is 2 days, the expected setting depth of a 36″ conductor should be 250 ft (76.2 m) and, similarly, 295 ft (89.9 m) for a 30″ conductor. The relationship between set-up period and surface conductor setting depth is established as well. Wellhead landed load appears to be the crucial factor for determining the conductor setting depth. The rationality of the newly developed shallow soil strength recovery model for the Equatorial Guinea deep-water block was also confirmed by the field data.

Research on Nano-Emulsion Relieving Coal Seam Water Block Damage

Hydraulic fracturing is the most effective reservoirstimulation techniques in the coalbed methane. However, the polymer in the fracturing fluid has a strong effect on the surface of the coal, causing the water lock damage as high as 70% to 90%. It is important to develop an efficient method for releasing coal seam water lock. In this paper, adsorption experiment, SEM, particle size experiment, core flow experiment, wettability and surface tension experiment are used to study the cause of coal seam water lock damage during fracturing and the effect of nano-emulsion on releasing water lock damage in coal seams. Experimental results show that after coal fracturing, the adsorption amount of polymer on the surface of coal is 14.81 mg/g. The large amount of hydrophilic polymer adsorption causes the pore radius of the coal to narrow. And the surface wettability changes from weak hydrophilic to strong hydrophilic, which increase the water lock damage. Compared with conventional slick water, fracturing fluid, the composite of nano-emulsion and fracturing fluid forms mixed micelles, which reduces the polymer adsorption capacity from 14.81 mg/g to 7.42 mg/g. After scanning by electron microscope, it is observed that the surface roughness of the rock sample is restored; The size of the nano-emulsion is about 10nm, and the very small volume can act deep in the pores of the coal seam; After using nano-emulsion, the gas/water interfacial tension is reduced by 45.1mN/m, and the wettability of coal is improved from hydrophilic to neutral, which reduces the capillary pressure in the pores of the coal and reduces the breakthrough pressure of coalbed methane by 11.1KPa; The water lock release rate is as high as 53.09%. The Nano-emulsion is an ideal choice to remove water lock damage.

A laboratory approach to predict the water-based drill-in fluid damage on a shale formation

Shale gas production after drill-in, completion, and hydraulic fracturing is strongly affected by formation damage. In order to determine the damage mechanisms for nonmarine shale reservoir, a series of assessments of sensitivity damage, water block damage, water-based drill-in fluids damage, and water damage to gas diffusion on 20 shale samples obtained from Chang 7 Formation were conducted and analyzed. Results indicate that, in the Chang 7 Formation shale, there is extremely strong stress sensitivity and moderately weak water sensitivity damage. Although the liquid phase invasion depth is shallow and the water block damage is limited, the liquid phase and solid particles would enter the microfractures in the reservoir.The P-1 water-based drill-in fluid is compatible with the Chang 7 Formation shale reservoir which can meet the requirement of Chang 7 Formation shale damage controlling, the effect of water-based drill-in fluid on wellbore stability should be paid more attention. The diffusion coefficient of the shale decreases with the presence of water.A systematic damage evaluation method of working fluid considering the multi-mechanism and multi-scale mass transfer process of shale gas is needed to establish.

UJI KINERJA MOVABLE THERMOSTATIC BATH SEBAGAI ALAT KALIBRASI TERMOKOPEL

<p>Kalibrasi termokopel bertujuan agar termokopel memiliki spesifikasi yang sesuai dengan standar nasional maupun <em>international</em> ISO/IEC 17025. Manfaat dari kalibrasi adalah menjaga kondisi instrumen ukur dan bahan ukur agar tetap sesuai dengan spesifikasinya. Berdasarkan hal tersebut dilakukan desain dan pembuatan <em>thermostatic bath</em> untuk kalibrasi termokopel, dengan menggunakan <em>thermoelectric cooler</em> (TEC) sebagai media pendingin fluida. Kemampuan <em>thermostatic bath</em> untuk kalibrasi termokopel dengan menggunakan TEC sebagai media pendingin fluida dan untuk mengetahui kinerja TEC. Melakukan <em>set</em><em>-up</em> variasi temperatur uji di temperatur 25°C, 20°C, 15°C, 10°C, dan temperatur paling rendah (diperoleh 6°C). Setelah mencapai nilai <em>set</em><em>-up</em> temperatur, kemudian dilakukan <em>setting</em> selama 3600 detik. Panas yang dihasilkan dari TEC diserap fluida melalui <em>water block</em> kemudian fluida dipompa menuju radiator untuk membuang panas ke lingkungan. Kipas radiator digunakan untuk mempercepat pelepasan panas pada sirip-sirip radiator ke udara sehingga pelepasan dari system ke lingkungan berjalan lebih cepat. Termostat W1209 digunakan untuk mengatur <em>set</em><em>-up </em>temperatur dan <em>data</em><em> logger</em> sebagai pendeteksi perubahan temperatur. Hasil pengujian <em>thermostatic bath</em>, TEC pada tegangan 12V, 10A mampu menurunkan temperatur air kapasitas 1,9 liter, dari temperatur awal 26,2°C hingga 6°C membutuhkan waktu selama 11 jam 37 menit (41855 detik).</p>