Application foam agent to foam cement slurry for geothermal well drilling

Abstract Geothermal energy is used in more than 20 countries worldwide and is a clean, reliable, and relatively available energy source. Nevertheless, to make geothermal energy available anywhere in the world, technical and economic challenges need to be addressed. Drilling especially is a technical challenge and comprises a significant part of the geothermal development cost. An enhanced geothermal system (EGS) is a commercially viable thermal reservoir where two wells are interconnected by some form of hydraulic stimulation. In a commercial setting, fluid is injected into this hot rock and passes between wells through a network of natural and induced fractures to transport heat to the surface system for electricity generation. To construct EGS wells, vertical and directional drilling is necessary with purpose-built drilling and steering equipment. This is an application where oil-and-gas drilling tools and techniques can be applied. A recent well, 16A(78)-32, drilled as part of the US Department of Energy's (DOE's) Utah Frontier Observatory for Research in Geothermal Energy (FORGE) program, highlights some of the technical challenges, which include drilling an accurate vertical section, a curve section, and a 5300-ft 65° tangent section in a hard granitic formation at temperatures up to 450°F (232°C). Extensive downhole temperature simulations were performed to select fit-for-purpose drilling equipment such as purely mechanical vertical drilling tools, instrumented steerable downhole motors, measurement-while-drilling (MWD) tools, and embedded high-frequency drilling dynamics recorders. Downhole and surface drilling dynamics data were used to fine- tune bit design and motor power section selection and continuously improve the durability of equipment, drilling efficiency, and footage drilled. Drilling optimization techniques used in oil and gas settings were successfully applied to this well, including analysis of data from drilling dynamics sensors embedded in the steerable motors and vertical drilling tools, surface surveillance of mechanical specific energy (MSE), and adopting a drilling parameter roadmap to improve drilling efficiency to minimize drilling dysfunctions and equipment damages. Through drilling optimization practices, the instrumented steerable motors with proper bit selections were able to drill more than 40 ft/hr on average, doubling the rate of penetration (ROP), footage, and run length experienced in previous granite wells. This paper presents a case study in which cutting-edge oil-and-gas drilling technologies were successfully applied to reduce the geothermal well drilling time by approximately half.

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Unit Quaternion Description Method for Detecting High-Temperature Geothermal Well Drilling Conditions

Geofluids ◽

10.1155/2021/9972138 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Hongyan Li ◽

Pengtao Wang ◽

Bin Liu ◽

Xianyu Zhang ◽

Hai Huang ◽

...

Keyword(s):

High Temperature ◽

Detection Efficiency ◽

Principal Component ◽

Kernel Principal Component Analysis ◽

Unit Quaternion ◽

Well Drilling ◽

Geothermal Well ◽

Geothermal Wells ◽

Time Required ◽

Drilling Conditions

When the typically utilized method for detecting the drilling conditions of high-temperature geothermal wells is applied, the detection takes a long time, the detection results are inconsistent with the actual conditions, and there are problems such as low detection efficiency and large detection deviation. Therefore, a method for detecting the drilling conditions of high-temperature geothermal wells described by a unit quaternion is proposed. Based on quaternion theory, the quaternion model of the position and attitude is constructed to obtain the drilling attitude. According to the analysis results and the basic principle of kernel principal component analysis, a model is built to realize the detection of high-temperature geothermal well drilling conditions. The experimental results show that in many iterations, the time required is stable and lower than that of other comparison methods, and the detection errors are all lower than 10%. The proposed method has high detection efficiency and low detection errors.

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Geothermal well drilling

Geothermal Power Generation ◽

10.1016/b978-0-08-100337-4.00005-x ◽

2016 ◽

pp. 107-139 ◽

Cited By ~ 1

Author(s):

L.E. Capuano

Keyword(s):

Well Drilling ◽

Geothermal Well

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Infill Depleted Gas Well Cementing Challenges for Offshore Myanmar Drilling Operations

10.2118/201010-ms ◽

2021 ◽

Author(s):

Ajita Ang C K Ang ◽

Avinash A Kumar Kumar ◽

Syazwan B A Ghani Ghani ◽

Nann N N Maung Nann ◽

M Hanif Yusof Yusoff ◽

...

Keyword(s):

Water Production ◽

Cement Slurry ◽

Water Contact ◽

Gas Well ◽

Well Drilling ◽

Depletion Rate ◽

Open Hole ◽

Drilling Operations ◽

Sensitivity Studies ◽

Remedial Work

Abstract Infill well drilling was planned and executed to increase production in a significantly depleted field. A total of 3 infill wells were drilled in 2 different layers of reservoir for an offshore operator in Myanmar. In the offset wells, water production had become significantly higher throughout. Previously all offset wells in this field were completed with open hole sand screens was chosen to isolate the water bearing sand in the sand reservoir below. Pore pressure prognosis were calculated from offset well depletion rate. Reservoir formation properties is assumed to be same throughout the field. The first well was drilled and was found that there were two gas water contacts through the 3 targeted sand layers. The gas water contact and WUT (Water Up To) in this well were unexpected and it was prognosed that these gas water contact are there due to compartmentalization. The 7" liner were set and cemented throughout these reservoirs. The cement job went as per the plan and there were no losses recorded during cementing. However, initial cement log did not show isolation. 2 more runs of cement log were performed 6 days and 10 days later while conducting intervention activities on other wells. All three cement log came to the same conclusion, showing no isolation throughout the annulus of the 7" production liner. Significant amount of gas had percolated into the annulus over time. Despite no evidence of poor cement slurry design observed during running various sensitivity studies and post-job lab tests final cement log, which was conducted under pressure and confirmed no hydraulic isolation. A cement remedial job was planned and an investigation was conducted to identify the plausible root causes. This paper explains on the root causes of poor cement presence in the annulus, and the remedial work that took place to rectify the issue.

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On specification of relaxation time for subsurface rocks composing borehole walls in geothermal well drilling

Azerbaijan Oil Industry ◽

10.37474/0365-8554/2020-11-26-29 ◽

2020 ◽

pp. 26-29

Author(s):

T.Sh. Salavatov ◽

◽

Y.I. Safarov ◽

S.A. Musayeva ◽

◽

...

Keyword(s):

Relaxation Time ◽

Pressure Fluctuations ◽

Borehole Wall ◽

Stationary Motion ◽

Circulation System ◽

Calculation Formula ◽

Drilling Mud ◽

Well Drilling ◽

Time Consumption ◽

Geothermal Well

The paper makes an effort to specify the relaxation time of subsurface rocks composing the borehole wall during geothermal well drilling justifying theoretical and practical researches. To solve mentioned issues, a theory of dumping of pressure fluctuations in non-stationary motion of drilling mud in the circulation system of well, based on the data of change of pressure and time consumption is applied and as a result a calculation formula obtained. The method has been tested in the well No 245 in Muradkhanly area.

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